RELEASES.md

   1 Version 1.49.0 (2020-12-31)
   2 ============================
   3
   4 Language
   5 -----------------------
   6
   7 - [Unions can now implement `Drop`, and you can now have a field in a union
   8   with `ManuallyDrop<T>`.][77547]
   9 - [You can now cast uninhabited enums to integers.][76199]
  10 - [You can now bind by reference and by move in patterns.][76119] This
  11   allows you to selectively borrow individual components of a type. E.g.
  12   ```rust
  13   #[derive(Debug)]
  14   struct Person {
  15       name: String,
  16       age: u8,
  17   }
  18
  19   let person = Person {
  20       name: String::from("Alice"),
  21       age: 20,
  22   };
  23
  24   // `name` is moved out of person, but `age` is referenced.
  25   let Person { name, ref age } = person;
  26   println!("{} {}", name, age);
  27   ```
  28
  29 Compiler
  30 -----------------------
  31
  32 - [Added tier 1\* support for `aarch64-unknown-linux-gnu`.][78228]
  33 - [Added tier 2 support for `aarch64-apple-darwin`.][75991]
  34 - [Added tier 2 support for `aarch64-pc-windows-msvc`.][75914]
  35 - [Added tier 3 support for `mipsel-unknown-none`.][78676]
  36 - [Raised the minimum supported LLVM version to LLVM 9.][78848]
  37 - [Output from threads spawned in tests is now captured.][78227]
  38 - [Change os and vendor values to "none" and "unknown" for some targets][78951]
  39
  40 \* Refer to Rust's [platform support page][forge-platform-support] for more
  41 information on Rust's tiered platform support.
  42
  43 Libraries
  44 -----------------------
  45
  46 - [`RangeInclusive` now checks for exhaustion when calling `contains` and indexing.][78109]
  47 - [`ToString::to_string` now no longer shrinks the internal buffer in the default implementation.][77997]
  48 - [`ops::{Index, IndexMut}` are now implemented for fixed sized arrays of any length.][74989]
  49
  50 Stabilized APIs
  51 ---------------
  52
  53 - [`slice::select_nth_unstable`]
  54 - [`slice::select_nth_unstable_by`]
  55 - [`slice::select_nth_unstable_by_key`]
  56
  57 The following previously stable methods are now `const`.
  58
  59 - [`Poll::is_ready`]
  60 - [`Poll::is_pending`]
  61
  62 Cargo
  63 -----------------------
  64 - [Building a crate with `cargo-package` should now be independently reproducible.][cargo/8864]
  65 - [`cargo-tree` now marks proc-macro crates.][cargo/8765]
  66 - [Added `CARGO_PRIMARY_PACKAGE` build-time environment variable.][cargo/8758] This
  67   variable will be set if the crate being built is one the user selected to build, either
  68   with `-p` or through defaults.
  69 - [You can now use glob patterns when specifying packages & targets.][cargo/8752]
  70
  71
  72 Compatibility Notes
  73 -------------------
  74
  75 - [Demoted `i686-unknown-freebsd` from host tier 2 to target tier 2 support.][78746]
  76 - [Macros that end with a semi-colon are now treated as statements even if they expand to nothing.][78376]
  77 - [Rustc will now check for the validity of some built-in attributes on enum variants.][77015]
  78   Previously such invalid or unused attributes could be ignored.
  79 - Leading whitespace is stripped more uniformly in documentation comments, which may change behavior. You
  80   read [this post about the changes][rustdoc-ws-post] for more details.
  81 - [Trait bounds are no longer inferred for associated types.][79904]
  82
  83 Internal Only
  84 -------------
  85 These changes provide no direct user facing benefits, but represent significant
  86 improvements to the internals and overall performance of rustc and
  87 related tools.
  88
  89 - [rustc's internal crates are now compiled using the `initial-exec` Thread
  90   Local Storage model.][78201]
  91 - [Calculate visibilities once in resolve.][78077]
  92 - [Added `system` to the `llvm-libunwind` bootstrap config option.][77703]
  93 - [Added `--color` for configuring terminal color support to bootstrap.][79004]
  94
  95
  96 [75991]: https://github.com/rust-lang/rust/pull/75991
  97 [78951]: https://github.com/rust-lang/rust/pull/78951
  98 [78848]: https://github.com/rust-lang/rust/pull/78848
  99 [78746]: https://github.com/rust-lang/rust/pull/78746
 100 [78376]: https://github.com/rust-lang/rust/pull/78376
 101 [78228]: https://github.com/rust-lang/rust/pull/78228
 102 [78227]: https://github.com/rust-lang/rust/pull/78227
 103 [78201]: https://github.com/rust-lang/rust/pull/78201
 104 [78109]: https://github.com/rust-lang/rust/pull/78109
 105 [78077]: https://github.com/rust-lang/rust/pull/78077
 106 [77997]: https://github.com/rust-lang/rust/pull/77997
 107 [77703]: https://github.com/rust-lang/rust/pull/77703
 108 [77547]: https://github.com/rust-lang/rust/pull/77547
 109 [77015]: https://github.com/rust-lang/rust/pull/77015
 110 [76199]: https://github.com/rust-lang/rust/pull/76199
 111 [76119]: https://github.com/rust-lang/rust/pull/76119
 112 [75914]: https://github.com/rust-lang/rust/pull/75914
 113 [74989]: https://github.com/rust-lang/rust/pull/74989
 114 [79004]: https://github.com/rust-lang/rust/pull/79004
 115 [78676]: https://github.com/rust-lang/rust/pull/78676
 116 [79904]: https://github.com/rust-lang/rust/issues/79904
 117 [cargo/8864]: https://github.com/rust-lang/cargo/pull/8864
 118 [cargo/8765]: https://github.com/rust-lang/cargo/pull/8765
 119 [cargo/8758]: https://github.com/rust-lang/cargo/pull/8758
 120 [cargo/8752]: https://github.com/rust-lang/cargo/pull/8752
 121 [`slice::select_nth_unstable`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable
 122 [`slice::select_nth_unstable_by`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable_by
 123 [`slice::select_nth_unstable_by_key`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable_by_key
 124 [`hint::spin_loop`]: https://doc.rust-lang.org/stable/std/hint/fn.spin_loop.html
 125 [`Poll::is_ready`]: https://doc.rust-lang.org/stable/std/task/enum.Poll.html#method.is_ready
 126 [`Poll::is_pending`]: https://doc.rust-lang.org/stable/std/task/enum.Poll.html#method.is_pending
 127 [rustdoc-ws-post]: https://blog.guillaume-gomez.fr/articles/2020-11-11+New+doc+comment+handling+in+rustdoc
 128
 129 Version 1.48.0 (2020-11-19)
 130 ==========================
 131
 132 Language
 133 --------
 134
 135 - [The `unsafe` keyword is now syntactically permitted on modules.][75857] This
 136   is still rejected *semantically*, but can now be parsed by procedural macros.
 137
 138 Compiler
 139 --------
 140 - [Stabilised the `-C link-self-contained=<yes|no>` compiler flag.][76158] This tells
 141   `rustc` whether to link its own C runtime and libraries or to rely on a external
 142   linker to find them. (Supported only on `windows-gnu`, `linux-musl`, and `wasi` platforms.)
 143 - [You can now use `-C target-feature=+crt-static` on `linux-gnu` targets.][77386]
 144   Note: If you're using cargo you must explicitly pass the `--target` flag.
 145 - [Added tier 2\* support for `aarch64-unknown-linux-musl`.][76420]
 146
 147 \* Refer to Rust's [platform support page][forge-platform-support] for more
 148 information on Rust's tiered platform support.
 149
 150 Libraries
 151 ---------
 152 - [`io::Write` is now implemented for `&ChildStdin` `&Sink`, `&Stdout`,
 153   and `&Stderr`.][76275]
 154 - [All arrays of any length now implement `TryFrom<Vec<T>>`.][76310]
 155 - [The `matches!` macro now supports having a trailing comma.][74880]
 156 - [`Vec<A>` now implements `PartialEq<[B]>` where `A: PartialEq<B>`.][74194]
 157 - [The `RefCell::{replace, replace_with, clone}` methods now all use `#[track_caller]`.][77055]
 158
 159 Stabilized APIs
 160 ---------------
 161 - [`slice::as_ptr_range`]
 162 - [`slice::as_mut_ptr_range`]
 163 - [`VecDeque::make_contiguous`]
 164 - [`future::pending`]
 165 - [`future::ready`]
 166
 167 The following previously stable methods are now `const fn`'s:
 168
 169 - [`Option::is_some`]
 170 - [`Option::is_none`]
 171 - [`Option::as_ref`]
 172 - [`Result::is_ok`]
 173 - [`Result::is_err`]
 174 - [`Result::as_ref`]
 175 - [`Ordering::reverse`]
 176 - [`Ordering::then`]
 177
 178 Cargo
 179 -----
 180
 181 Rustdoc
 182 -------
 183 - [You can now link to items in `rustdoc` using the intra-doc link
 184   syntax.][74430] E.g. ``/// Uses [`std::future`]`` will automatically generate
 185   a link to `std::future`'s documentation. See ["Linking to items by
 186   name"][intradoc-links] for more information.
 187 - [You can now specify `#[doc(alias = "<alias>")]` on items to add search aliases
 188   when searching through `rustdoc`'s UI.][75740]
 189
 190 Compatibility Notes
 191 -------------------
 192 - [Promotion of references to `'static` lifetime inside `const fn` now follows the
 193   same rules as inside a `fn` body.][75502] In particular, `&foo()` will not be
 194   promoted to `'static` lifetime any more inside `const fn`s.
 195 - [Associated type bindings on trait objects are now verified to meet the bounds
 196   declared on the trait when checking that they implement the trait.][27675]
 197 - [When trait bounds on associated types or opaque types are ambiguous, the
 198   compiler no longer makes an arbitrary choice on which bound to use.][54121]
 199 - [Fixed recursive nonterminals not being expanded in macros during
 200   pretty-print/reparse check.][77153] This may cause errors if your macro wasn't
 201   correctly handling recursive nonterminal tokens.
 202 - [`&mut` references to non zero-sized types are no longer promoted.][75585]
 203 - [`rustc` will now warn if you use attributes like `#[link_name]` or `#[cold]`
 204   in places where they have no effect.][73461]
 205 - [Updated `_mm256_extract_epi8` and `_mm256_extract_epi16` signatures in
 206   `arch::{x86, x86_64}` to return `i32` to match the vendor signatures.][73166]
 207 - [`mem::uninitialized` will now panic if any inner types inside a struct or enum
 208   disallow zero-initialization.][71274]
 209 - [`#[target_feature]` will now error if used in a place where it has no effect.][78143]
 210 - [Foreign exceptions are now caught by `catch_unwind` and will cause an abort.][70212]
 211   Note: This behaviour is not guaranteed and is still considered undefined behaviour,
 212   see the [`catch_unwind`] documentation for further information.
 213
 214
 215
 216 Internal Only
 217 -------------
 218 These changes provide no direct user facing benefits, but represent significant
 219 improvements to the internals and overall performance of rustc and
 220 related tools.
 221
 222 - [Building `rustc` from source now uses `ninja` by default over `make`.][74922]
 223   You can continue building with `make` by setting `ninja=false` in
 224   your `config.toml`.
 225 - [cg_llvm: `fewer_names` in `uncached_llvm_type`][76030]
 226 - [Made `ensure_sufficient_stack()` non-generic][76680]
 227
 228 [78143]: https://github.com/rust-lang/rust/issues/78143
 229 [76680]: https://github.com/rust-lang/rust/pull/76680/
 230 [76030]: https://github.com/rust-lang/rust/pull/76030/
 231 [70212]: https://github.com/rust-lang/rust/pull/70212/
 232 [27675]: https://github.com/rust-lang/rust/issues/27675/
 233 [54121]: https://github.com/rust-lang/rust/issues/54121/
 234 [71274]: https://github.com/rust-lang/rust/pull/71274/
 235 [77386]: https://github.com/rust-lang/rust/pull/77386/
 236 [77153]: https://github.com/rust-lang/rust/pull/77153/
 237 [77055]: https://github.com/rust-lang/rust/pull/77055/
 238 [76275]: https://github.com/rust-lang/rust/pull/76275/
 239 [76310]: https://github.com/rust-lang/rust/pull/76310/
 240 [76420]: https://github.com/rust-lang/rust/pull/76420/
 241 [76158]: https://github.com/rust-lang/rust/pull/76158/
 242 [75857]: https://github.com/rust-lang/rust/pull/75857/
 243 [75585]: https://github.com/rust-lang/rust/pull/75585/
 244 [75740]: https://github.com/rust-lang/rust/pull/75740/
 245 [75502]: https://github.com/rust-lang/rust/pull/75502/
 246 [74880]: https://github.com/rust-lang/rust/pull/74880/
 247 [74922]: https://github.com/rust-lang/rust/pull/74922/
 248 [74430]: https://github.com/rust-lang/rust/pull/74430/
 249 [74194]: https://github.com/rust-lang/rust/pull/74194/
 250 [73461]: https://github.com/rust-lang/rust/pull/73461/
 251 [73166]: https://github.com/rust-lang/rust/pull/73166/
 252 [intradoc-links]: https://doc.rust-lang.org/rustdoc/linking-to-items-by-name.html
 253 [`catch_unwind`]: https://doc.rust-lang.org/std/panic/fn.catch_unwind.html
 254 [`Option::is_some`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_some
 255 [`Option::is_none`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_none
 256 [`Option::as_ref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_ref
 257 [`Result::is_ok`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.is_ok
 258 [`Result::is_err`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.is_err
 259 [`Result::as_ref`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.as_ref
 260 [`Ordering::reverse`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.reverse
 261 [`Ordering::then`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.then
 262 [`slice::as_ptr_range`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr_range
 263 [`slice::as_mut_ptr_range`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_mut_ptr_range
 264 [`VecDeque::make_contiguous`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.make_contiguous
 265 [`future::pending`]: https://doc.rust-lang.org/std/future/fn.pending.html
 266 [`future::ready`]: https://doc.rust-lang.org/std/future/fn.ready.html
 267
 268
 269 Version 1.47.0 (2020-10-08)
 270 ==========================
 271
 272 Language
 273 --------
 274 - [Closures will now warn when not used.][74869]
 275
 276 Compiler
 277 --------
 278 - [Stabilized the `-C control-flow-guard` codegen option][73893], which enables
 279   [Control Flow Guard][1.47.0-cfg] for Windows platforms, and is ignored on other
 280   platforms.
 281 - [Upgraded to LLVM 11.][73526]
 282 - [Added tier 3\* support for the `thumbv4t-none-eabi` target.][74419]
 283 - [Upgrade the FreeBSD toolchain to version 11.4][75204]
 284 - [`RUST_BACKTRACE`'s output is now more compact.][75048]
 285
 286 \* Refer to Rust's [platform support page][forge-platform-support] for more
 287 information on Rust's tiered platform support.
 288
 289 Libraries
 290 ---------
 291 - [`CStr` now implements `Index<RangeFrom<usize>>`.][74021]
 292 - [Traits in `std`/`core` are now implemented for arrays of any length, not just
 293   those of length less than 33.][74060]
 294 - [`ops::RangeFull` and `ops::Range` now implement Default.][73197]
 295 - [`panic::Location` now implements `Copy`, `Clone`, `Eq`, `Hash`, `Ord`,
 296   `PartialEq`, and `PartialOrd`.][73583]
 297
 298 Stabilized APIs
 299 ---------------
 300 - [`Ident::new_raw`]
 301 - [`Range::is_empty`]
 302 - [`RangeInclusive::is_empty`]
 303 - [`Result::as_deref`]
 304 - [`Result::as_deref_mut`]
 305 - [`Vec::leak`]
 306 - [`pointer::offset_from`]
 307 - [`f32::TAU`]
 308 - [`f64::TAU`]
 309
 310 The following previously stable APIs have now been made const.
 311
 312 - [The `new` method for all `NonZero` integers.][73858]
 313 - [The `checked_add`,`checked_sub`,`checked_mul`,`checked_neg`, `checked_shl`,
 314   `checked_shr`, `saturating_add`, `saturating_sub`, and `saturating_mul`
 315   methods for all integers.][73858]
 316 - [The `checked_abs`, `saturating_abs`, `saturating_neg`, and `signum`  for all
 317   signed integers.][73858]
 318 - [The `is_ascii_alphabetic`, `is_ascii_uppercase`, `is_ascii_lowercase`,
 319   `is_ascii_alphanumeric`, `is_ascii_digit`, `is_ascii_hexdigit`,
 320   `is_ascii_punctuation`, `is_ascii_graphic`, `is_ascii_whitespace`, and
 321   `is_ascii_control` methods for `char` and `u8`.][73858]
 322
 323 Cargo
 324 -----
 325 - [`build-dependencies` are now built with opt-level 0 by default.][cargo/8500]
 326   You can override this by setting the following in your `Cargo.toml`.
 327   ```toml
 328   [profile.release.build-override]
 329   opt-level = 3
 330   ```
 331 - [`cargo-help` will now display man pages for commands rather just the
 332   `--help` text.][cargo/8456]
 333 - [`cargo-metadata` now emits a `test` field indicating if a target has
 334   tests enabled.][cargo/8478]
 335 - [`workspace.default-members` now respects `workspace.exclude`.][cargo/8485]
 336 - [`cargo-publish` will now use an alternative registry by default if it's the
 337   only registry specified in `package.publish`.][cargo/8571]
 338
 339 Misc
 340 ----
 341 - [Added a help button beside Rustdoc's searchbar that explains rustdoc's
 342   type based search.][75366]
 343 - [Added the Ayu theme to rustdoc.][71237]
 344
 345 Compatibility Notes
 346 -------------------
 347 - [Bumped the minimum supported Emscripten version to 1.39.20.][75716]
 348 - [Fixed a regression parsing `{} && false` in tail expressions.][74650]
 349 - [Added changes to how proc-macros are expanded in `macro_rules!` that should
 350   help to preserve more span information.][73084] These changes may cause
 351   compiliation errors if your macro was unhygenic or didn't correctly handle
 352   `Delimiter::None`.
 353 - [Moved support for the CloudABI target to tier 3.][75568]
 354 - [`linux-gnu` targets now require minimum kernel 2.6.32 and glibc 2.11.][74163]
 355 - [Added the `rustc-docs` component.][75560] This allows you to install
 356   and read the documentation for the compiler internal APIs. (Currently only
 357   available for `x86_64-unknown-linux-gnu`.)
 358
 359 Internal Only
 360 --------
 361
 362 - [Improved default settings for bootstrapping in `x.py`.][73964] You can read details about this change in the ["Changes to `x.py` defaults"](https://blog.rust-lang.org/inside-rust/2020/08/30/changes-to-x-py-defaults.html) post on the Inside Rust blog.
 363
 364 [1.47.0-cfg]: https://docs.microsoft.com/en-us/windows/win32/secbp/control-flow-guard
 365 [75048]: https://github.com/rust-lang/rust/pull/75048/
 366 [74163]: https://github.com/rust-lang/rust/pull/74163/
 367 [71237]: https://github.com/rust-lang/rust/pull/71237/
 368 [74869]: https://github.com/rust-lang/rust/pull/74869/
 369 [73858]: https://github.com/rust-lang/rust/pull/73858/
 370 [75716]: https://github.com/rust-lang/rust/pull/75716/
 371 [75908]: https://github.com/rust-lang/rust/pull/75908/
 372 [75516]: https://github.com/rust-lang/rust/pull/75516/
 373 [75560]: https://github.com/rust-lang/rust/pull/75560/
 374 [75568]: https://github.com/rust-lang/rust/pull/75568/
 375 [75366]: https://github.com/rust-lang/rust/pull/75366/
 376 [75204]: https://github.com/rust-lang/rust/pull/75204/
 377 [74650]: https://github.com/rust-lang/rust/pull/74650/
 378 [74419]: https://github.com/rust-lang/rust/pull/74419/
 379 [73964]: https://github.com/rust-lang/rust/pull/73964/
 380 [74021]: https://github.com/rust-lang/rust/pull/74021/
 381 [74060]: https://github.com/rust-lang/rust/pull/74060/
 382 [73893]: https://github.com/rust-lang/rust/pull/73893/
 383 [73526]: https://github.com/rust-lang/rust/pull/73526/
 384 [73583]: https://github.com/rust-lang/rust/pull/73583/
 385 [73084]: https://github.com/rust-lang/rust/pull/73084/
 386 [73197]: https://github.com/rust-lang/rust/pull/73197/
 387 [72488]: https://github.com/rust-lang/rust/pull/72488/
 388 [cargo/8456]: https://github.com/rust-lang/cargo/pull/8456/
 389 [cargo/8478]: https://github.com/rust-lang/cargo/pull/8478/
 390 [cargo/8485]: https://github.com/rust-lang/cargo/pull/8485/
 391 [cargo/8500]: https://github.com/rust-lang/cargo/pull/8500/
 392 [cargo/8571]: https://github.com/rust-lang/cargo/pull/8571/
 393 [`Ident::new_raw`]:  https://doc.rust-lang.org/nightly/proc_macro/struct.Ident.html#method.new_raw
 394 [`Range::is_empty`]: https://doc.rust-lang.org/nightly/std/ops/struct.Range.html#method.is_empty
 395 [`RangeInclusive::is_empty`]: https://doc.rust-lang.org/nightly/std/ops/struct.RangeInclusive.html#method.is_empty
 396 [`Result::as_deref_mut`]: https://doc.rust-lang.org/nightly/std/result/enum.Result.html#method.as_deref_mut
 397 [`Result::as_deref`]: https://doc.rust-lang.org/nightly/std/result/enum.Result.html#method.as_deref
 398 [`TypeId::of`]: https://doc.rust-lang.org/nightly/std/any/struct.TypeId.html#method.of
 399 [`Vec::leak`]: https://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#method.leak
 400 [`f32::TAU`]: https://doc.rust-lang.org/nightly/std/f32/consts/constant.TAU.html
 401 [`f64::TAU`]: https://doc.rust-lang.org/nightly/std/f64/consts/constant.TAU.html
 402 [`pointer::offset_from`]: https://doc.rust-lang.org/nightly/std/primitive.pointer.html#method.offset_from
 403
 404
 405 Version 1.46.0 (2020-08-27)
 406 ==========================
 407
 408 Language
 409 --------
 410 - [`if`, `match`, and `loop` expressions can now be used in const functions.][72437]
 411 - [Additionally you are now also able to coerce and cast to slices (`&[T]`) in
 412   const functions.][73862]
 413 - [The `#[track_caller]` attribute can now be added to functions to use the
 414   function's caller's location information for panic messages.][72445]
 415 - [Recursively indexing into tuples no longer needs parentheses.][71322] E.g.
 416   `x.0.0` over `(x.0).0`.
 417 - [`mem::transmute` can now be used in statics and constants.][72920] **Note**
 418   You currently can't use `mem::transmute` in constant functions.
 419
 420 Compiler
 421 --------
 422 - [You can now use the `cdylib` target on Apple iOS and tvOS platforms.][73516]
 423 - [Enabled static "Position Independent Executables" by default
 424   for `x86_64-unknown-linux-musl`.][70740]
 425
 426 Libraries
 427 ---------
 428 - [`mem::forget` is now a `const fn`.][73887]
 429 - [`String` now implements `From<char>`.][73466]
 430 - [The `leading_ones`, and `trailing_ones` methods have been stabilised for all
 431   integer types.][73032]
 432 - [`vec::IntoIter<T>` now implements `AsRef<[T]>`.][72583]
 433 - [All non-zero integer types (`NonZeroU8`) now implement `TryFrom` for their
 434   zero-able equivalent (e.g. `TryFrom<u8>`).][72717]
 435 - [`&[T]` and `&mut [T]` now implement `PartialEq<Vec<T>>`.][71660]
 436 - [`(String, u16)` now implements `ToSocketAddrs`.][73007]
 437 - [`vec::Drain<'_, T>` now implements `AsRef<[T]>`.][72584]
 438
 439 Stabilized APIs
 440 ---------------
 441 - [`Option::zip`]
 442 - [`vec::Drain::as_slice`]
 443
 444 Cargo
 445 -----
 446 Added a number of new environment variables that are now available when
 447 compiling your crate.
 448
 449 - [`CARGO_BIN_NAME` and `CARGO_CRATE_NAME`][cargo/8270] Providing the name of
 450   the specific binary being compiled and the name of the crate.
 451 - [`CARGO_PKG_LICENSE`][cargo/8325] The license from the manifest of the package.
 452 - [`CARGO_PKG_LICENSE_FILE`][cargo/8387] The path to the license file.
 453
 454 Compatibility Notes
 455 -------------------
 456 - [The target configuration option `abi_blacklist` has been renamed
 457   to `unsupported_abis`.][74150] The old name will still continue to work.
 458 - [Rustc will now warn if you cast a C-like enum that implements `Drop`.][72331]
 459   This was previously accepted but will become a hard error in a future release.
 460 - [Rustc will fail to compile if you have a struct with
 461   `#[repr(i128)]` or `#[repr(u128)]`.][74109] This representation is currently only
 462   allowed on `enum`s.
 463 - [Tokens passed to `macro_rules!` are now always captured.][73293] This helps
 464   ensure that spans have the correct information, and may cause breakage if you
 465   were relying on receiving spans with dummy information.
 466 - [The InnoSetup installer for Windows is no longer available.][72569] This was
 467   a legacy installer that was replaced by a MSI installer a few years ago but
 468   was still being built.
 469 - [`{f32, f64}::asinh` now returns the correct values for negative numbers.][72486]
 470 - [Rustc will no longer accept overlapping trait implementations that only
 471   differ in how the lifetime was bound.][72493]
 472 - [Rustc now correctly relates the lifetime of an existential associated
 473   type.][71896] This fixes some edge cases where `rustc` would erroneously allow
 474   you to pass a shorter lifetime than expected.
 475 - [Rustc now dynamically links to `libz` (also called `zlib`) on Linux.][74420]
 476   The library will need to be installed for `rustc` to work, even though we
 477   expect it to be already available on most systems.
 478 - [Tests annotated with `#[should_panic]` are broken on ARMv7 while running
 479   under QEMU.][74820]
 480 - [Pretty printing of some tokens in procedural macros changed.][75453] The
 481   exact output returned by rustc's pretty printing is an unstable
 482   implementation detail: we recommend any macro relying on it to switch to a
 483   more robust parsing system.
 484
 485 [75453]: https://github.com/rust-lang/rust/issues/75453/
 486 [74820]: https://github.com/rust-lang/rust/issues/74820/
 487 [74420]: https://github.com/rust-lang/rust/issues/74420/
 488 [74109]: https://github.com/rust-lang/rust/pull/74109/
 489 [74150]: https://github.com/rust-lang/rust/pull/74150/
 490 [73862]: https://github.com/rust-lang/rust/pull/73862/
 491 [73887]: https://github.com/rust-lang/rust/pull/73887/
 492 [73466]: https://github.com/rust-lang/rust/pull/73466/
 493 [73516]: https://github.com/rust-lang/rust/pull/73516/
 494 [73293]: https://github.com/rust-lang/rust/pull/73293/
 495 [73007]: https://github.com/rust-lang/rust/pull/73007/
 496 [73032]: https://github.com/rust-lang/rust/pull/73032/
 497 [72920]: https://github.com/rust-lang/rust/pull/72920/
 498 [72569]: https://github.com/rust-lang/rust/pull/72569/
 499 [72583]: https://github.com/rust-lang/rust/pull/72583/
 500 [72584]: https://github.com/rust-lang/rust/pull/72584/
 501 [72717]: https://github.com/rust-lang/rust/pull/72717/
 502 [72437]: https://github.com/rust-lang/rust/pull/72437/
 503 [72445]: https://github.com/rust-lang/rust/pull/72445/
 504 [72486]: https://github.com/rust-lang/rust/pull/72486/
 505 [72493]: https://github.com/rust-lang/rust/pull/72493/
 506 [72331]: https://github.com/rust-lang/rust/pull/72331/
 507 [71896]: https://github.com/rust-lang/rust/pull/71896/
 508 [71660]: https://github.com/rust-lang/rust/pull/71660/
 509 [71322]: https://github.com/rust-lang/rust/pull/71322/
 510 [70740]: https://github.com/rust-lang/rust/pull/70740/
 511 [cargo/8270]: https://github.com/rust-lang/cargo/pull/8270/
 512 [cargo/8325]: https://github.com/rust-lang/cargo/pull/8325/
 513 [cargo/8387]: https://github.com/rust-lang/cargo/pull/8387/
 514 [`Option::zip`]: https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.zip
 515 [`vec::Drain::as_slice`]: https://doc.rust-lang.org/stable/std/vec/struct.Drain.html#method.as_slice
 516
 517
 518 Version 1.45.2 (2020-08-03)
 519 ==========================
 520
 521 * [Fix bindings in tuple struct patterns][74954]
 522 * [Fix track_caller integration with trait objects][74784]
 523
 524 [74954]: https://github.com/rust-lang/rust/issues/74954
 525 [74784]: https://github.com/rust-lang/rust/issues/74784
 526
 527
 528 Version 1.45.1 (2020-07-30)
 529 ==========================
 530
 531 * [Fix const propagation with references.][73613]
 532 * [rustfmt accepts rustfmt_skip in cfg_attr again.][73078]
 533 * [Avoid spurious implicit region bound.][74509]
 534 * [Install clippy on x.py install][74457]
 535
 536 [73613]: https://github.com/rust-lang/rust/pull/73613
 537 [73078]: https://github.com/rust-lang/rust/issues/73078
 538 [74509]: https://github.com/rust-lang/rust/pull/74509
 539 [74457]: https://github.com/rust-lang/rust/pull/74457
 540
 541
 542 Version 1.45.0 (2020-07-16)
 543 ==========================
 544
 545 Language
 546 --------
 547 - [Out of range float to int conversions using `as` has been defined as a saturating
 548   conversion.][71269] This was previously undefined behaviour, but you can use the
 549    `{f64, f32}::to_int_unchecked` methods to continue using the current behaviour, which
 550    may be desirable in rare performance sensitive situations.
 551 - [`mem::Discriminant<T>` now uses `T`'s discriminant type instead of always
 552   using `u64`.][70705]
 553 - [Function like procedural macros can now be used in expression, pattern, and  statement
 554   positions.][68717] This means you can now use a function-like procedural macro
 555   anywhere you can use a declarative (`macro_rules!`) macro.
 556
 557 Compiler
 558 --------
 559 - [You can now override individual target features through the `target-feature`
 560   flag.][72094] E.g. `-C target-feature=+avx2 -C target-feature=+fma` is now
 561   equivalent to `-C target-feature=+avx2,+fma`.
 562 - [Added the `force-unwind-tables` flag.][69984] This option allows
 563   rustc to always generate unwind tables regardless of panic strategy.
 564 - [Added the `embed-bitcode` flag.][71716] This codegen flag allows rustc
 565   to include LLVM bitcode into generated `rlib`s (this is on by default).
 566 - [Added the `tiny` value to the `code-model` codegen flag.][72397]
 567 - [Added tier 3 support\* for the `mipsel-sony-psp` target.][72062]
 568 - [Added tier 3 support for the `thumbv7a-uwp-windows-msvc` target.][72133]
 569 - [Upgraded to LLVM 10.][67759]
 570
 571 \* Refer to Rust's [platform support page][forge-platform-support] for more
 572 information on Rust's tiered platform support.
 573
 574
 575 Libraries
 576 ---------
 577 - [`net::{SocketAddr, SocketAddrV4, SocketAddrV6}` now implements `PartialOrd`
 578   and `Ord`.][72239]
 579 - [`proc_macro::TokenStream` now implements `Default`.][72234]
 580 - [You can now use `char` with
 581   `ops::{Range, RangeFrom, RangeFull, RangeInclusive, RangeTo}` to iterate over
 582   a range of codepoints.][72413] E.g.
 583   you can now write the following;
 584   ```rust
 585   for ch in 'a'..='z' {
 586       print!("{}", ch);
 587   }
 588   println!();
 589   // Prints "abcdefghijklmnopqrstuvwxyz"
 590   ```
 591 - [`OsString` now implements `FromStr`.][71662]
 592 - [The `saturating_neg` method has been added to all signed integer primitive
 593   types, and the `saturating_abs` method has been added for all integer
 594   primitive types.][71886]
 595 - [`Arc<T>`, `Rc<T>` now implement  `From<Cow<'_, T>>`, and `Box` now
 596   implements `From<Cow>` when `T` is `[T: Copy]`, `str`, `CStr`, `OsStr`,
 597   or `Path`.][71447]
 598 - [`Box<[T]>` now implements `From<[T; N]>`.][71095]
 599 - [`BitOr` and `BitOrAssign` are implemented for all `NonZero`
 600   integer types.][69813]
 601 - [The `fetch_min`, and `fetch_max` methods have been added to all atomic
 602   integer types.][72324]
 603 - [The `fetch_update` method has been added to all atomic integer types.][71843]
 604
 605 Stabilized APIs
 606 ---------------
 607 - [`Arc::as_ptr`]
 608 - [`BTreeMap::remove_entry`]
 609 - [`Rc::as_ptr`]
 610 - [`rc::Weak::as_ptr`]
 611 - [`rc::Weak::from_raw`]
 612 - [`rc::Weak::into_raw`]
 613 - [`str::strip_prefix`]
 614 - [`str::strip_suffix`]
 615 - [`sync::Weak::as_ptr`]
 616 - [`sync::Weak::from_raw`]
 617 - [`sync::Weak::into_raw`]
 618 - [`char::UNICODE_VERSION`]
 619 - [`Span::resolved_at`]
 620 - [`Span::located_at`]
 621 - [`Span::mixed_site`]
 622 - [`unix::process::CommandExt::arg0`]
 623
 624 Cargo
 625 -----
 626
 627 - [Cargo uses the `embed-bitcode` flag to optimize disk usage and build
 628   time.][cargo/8066]
 629
 630 Misc
 631 ----
 632 - [Rustdoc now supports strikethrough text in Markdown.][71928] E.g.
 633   `~~outdated information~~` becomes "~~outdated information~~".
 634 - [Added an emoji to Rustdoc's deprecated API message.][72014]
 635
 636 Compatibility Notes
 637 -------------------
 638 - [Trying to self initialize a static value (that is creating a value using
 639   itself) is unsound and now causes a compile error.][71140]
 640 - [`{f32, f64}::powi` now returns a slightly different value on Windows.][73420]
 641   This is due to changes in LLVM's intrinsics which `{f32, f64}::powi` uses.
 642 - [Rustdoc's CLI's extra error exit codes have been removed.][71900] These were
 643   previously undocumented and not intended for public use. Rustdoc still provides
 644   a non-zero exit code on errors.
 645 - [Rustc's `lto` flag is incompatible with the new `embed-bitcode=no`.][71848]
 646   This may cause issues if LTO is enabled through `RUSTFLAGS` or `cargo rustc`
 647   flags while cargo is adding `embed-bitcode` itself. The recommended way to
 648   control LTO is with Cargo profiles, either in `Cargo.toml` or `.cargo/config`,
 649   or by setting `CARGO_PROFILE_<name>_LTO` in the environment.
 650
 651 Internals Only
 652 --------------
 653 - [Make clippy a git subtree instead of a git submodule][70655]
 654 - [Unify the undo log of all snapshot types][69464]
 655
 656 [71848]: https://github.com/rust-lang/rust/issues/71848/
 657 [73420]: https://github.com/rust-lang/rust/issues/73420/
 658 [72324]: https://github.com/rust-lang/rust/pull/72324/
 659 [71843]: https://github.com/rust-lang/rust/pull/71843/
 660 [71886]: https://github.com/rust-lang/rust/pull/71886/
 661 [72234]: https://github.com/rust-lang/rust/pull/72234/
 662 [72239]: https://github.com/rust-lang/rust/pull/72239/
 663 [72397]: https://github.com/rust-lang/rust/pull/72397/
 664 [72413]: https://github.com/rust-lang/rust/pull/72413/
 665 [72014]: https://github.com/rust-lang/rust/pull/72014/
 666 [72062]: https://github.com/rust-lang/rust/pull/72062/
 667 [72094]: https://github.com/rust-lang/rust/pull/72094/
 668 [72133]: https://github.com/rust-lang/rust/pull/72133/
 669 [67759]: https://github.com/rust-lang/rust/pull/67759/
 670 [71900]: https://github.com/rust-lang/rust/pull/71900/
 671 [71928]: https://github.com/rust-lang/rust/pull/71928/
 672 [71662]: https://github.com/rust-lang/rust/pull/71662/
 673 [71716]: https://github.com/rust-lang/rust/pull/71716/
 674 [71447]: https://github.com/rust-lang/rust/pull/71447/
 675 [71269]: https://github.com/rust-lang/rust/pull/71269/
 676 [71095]: https://github.com/rust-lang/rust/pull/71095/
 677 [71140]: https://github.com/rust-lang/rust/pull/71140/
 678 [70655]: https://github.com/rust-lang/rust/pull/70655/
 679 [70705]: https://github.com/rust-lang/rust/pull/70705/
 680 [69984]: https://github.com/rust-lang/rust/pull/69984/
 681 [69813]: https://github.com/rust-lang/rust/pull/69813/
 682 [69464]: https://github.com/rust-lang/rust/pull/69464/
 683 [68717]: https://github.com/rust-lang/rust/pull/68717/
 684 [cargo/8066]: https://github.com/rust-lang/cargo/pull/8066
 685 [`Arc::as_ptr`]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.as_ptr
 686 [`BTreeMap::remove_entry`]: https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.remove_entry
 687 [`Rc::as_ptr`]: https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.as_ptr
 688 [`rc::Weak::as_ptr`]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.as_ptr
 689 [`rc::Weak::from_raw`]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.from_raw
 690 [`rc::Weak::into_raw`]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.into_raw
 691 [`sync::Weak::as_ptr`]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.as_ptr
 692 [`sync::Weak::from_raw`]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.from_raw
 693 [`sync::Weak::into_raw`]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.into_raw
 694 [`str::strip_prefix`]: https://doc.rust-lang.org/stable/std/primitive.str.html#method.strip_prefix
 695 [`str::strip_suffix`]: https://doc.rust-lang.org/stable/std/primitive.str.html#method.strip_suffix
 696 [`char::UNICODE_VERSION`]: https://doc.rust-lang.org/stable/std/char/constant.UNICODE_VERSION.html
 697 [`Span::resolved_at`]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.resolved_at
 698 [`Span::located_at`]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.located_at
 699 [`Span::mixed_site`]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.mixed_site
 700 [`unix::process::CommandExt::arg0`]: https://doc.rust-lang.org/std/os/unix/process/trait.CommandExt.html#tymethod.arg0
 701
 702
 703 Version 1.44.1 (2020-06-18)
 704 ===========================
 705
 706 * [rustfmt accepts rustfmt_skip in cfg_attr again.][73078]
 707 * [Don't hash executable filenames on apple platforms, fixing backtraces.][cargo/8329]
 708 * [Fix crashes when finding backtrace on macOS.][71397]
 709 * [Clippy applies lint levels into different files.][clippy/5356]
 710
 711 [71397]: https://github.com/rust-lang/rust/issues/71397
 712 [73078]: https://github.com/rust-lang/rust/issues/73078
 713 [cargo/8329]: https://github.com/rust-lang/cargo/pull/8329
 714 [clippy/5356]: https://github.com/rust-lang/rust-clippy/issues/5356
 715
 716
 717 Version 1.44.0 (2020-06-04)
 718 ==========================
 719
 720 Language
 721 --------
 722 - [You can now use `async/.await` with `#[no_std]` enabled.][69033]
 723 - [Added the `unused_braces` lint.][70081]
 724
 725 **Syntax-only changes**
 726
 727 - [Expansion-driven outline module parsing][69838]
 728 ```rust
 729 #[cfg(FALSE)]
 730 mod foo {
 731     mod bar {
 732         mod baz; // `foo/bar/baz.rs` doesn't exist, but no error!
 733     }
 734 }
 735 ```
 736
 737 These are still rejected semantically, so you will likely receive an error but
 738 these changes can be seen and parsed by macros and conditional compilation.
 739
 740 Compiler
 741 --------
 742 - [Rustc now respects the `-C codegen-units` flag in incremental mode.][70156]
 743   Additionally when in incremental mode rustc defaults to 256 codegen units.
 744 - [Refactored `catch_unwind` to have zero-cost, unless unwinding is enabled and
 745   a panic is thrown.][67502]
 746 - [Added tier 3\* support for the `aarch64-unknown-none` and
 747   `aarch64-unknown-none-softfloat` targets.][68334]
 748 - [Added tier 3 support for `arm64-apple-tvos` and
 749   `x86_64-apple-tvos` targets.][68191]
 750
 751
 752 Libraries
 753 ---------
 754 - [Special cased `vec![]` to map directly to `Vec::new()`.][70632] This allows
 755   `vec![]` to be able to be used in `const` contexts.
 756 - [`convert::Infallible` now implements `Hash`.][70281]
 757 - [`OsString` now implements `DerefMut` and `IndexMut` returning
 758   a `&mut OsStr`.][70048]
 759 - [Unicode 13 is now supported.][69929]
 760 - [`String` now implements `From<&mut str>`.][69661]
 761 - [`IoSlice` now implements `Copy`.][69403]
 762 - [`Vec<T>` now implements `From<[T; N]>`.][68692] Where `N` is at most 32.
 763 - [`proc_macro::LexError` now implements `fmt::Display` and `Error`.][68899]
 764 - [`from_le_bytes`, `to_le_bytes`, `from_be_bytes`, `to_be_bytes`,
 765   `from_ne_bytes`, and `to_ne_bytes` methods are now `const` for all
 766   integer types.][69373]
 767
 768 Stabilized APIs
 769 ---------------
 770 - [`PathBuf::with_capacity`]
 771 - [`PathBuf::capacity`]
 772 - [`PathBuf::clear`]
 773 - [`PathBuf::reserve`]
 774 - [`PathBuf::reserve_exact`]
 775 - [`PathBuf::shrink_to_fit`]
 776 - [`f32::to_int_unchecked`]
 777 - [`f64::to_int_unchecked`]
 778 - [`Layout::align_to`]
 779 - [`Layout::pad_to_align`]
 780 - [`Layout::array`]
 781 - [`Layout::extend`]
 782
 783 Cargo
 784 -----
 785 - [Added the `cargo tree` command which will print a tree graph of
 786   your dependencies.][cargo/8062] E.g.
 787   ```
 788     mdbook v0.3.2 (/Users/src/rust/mdbook)
 789   ├── ammonia v3.0.0
 790   │   ├── html5ever v0.24.0
 791   │   │   ├── log v0.4.8
 792   │   │   │   └── cfg-if v0.1.9
 793   │   │   ├── mac v0.1.1
 794   │   │   └── markup5ever v0.9.0
 795   │   │       ├── log v0.4.8 (*)
 796   │   │       ├── phf v0.7.24
 797   │   │       │   └── phf_shared v0.7.24
 798   │   │       │       ├── siphasher v0.2.3
 799   │   │       │       └── unicase v1.4.2
 800   │   │       │           [build-dependencies]
 801   │   │       │           └── version_check v0.1.5
 802   ...
 803   ```
 804   You can also display dependencies on multiple versions of the same crate with
 805   `cargo tree -d` (short for `cargo tree --duplicates`).
 806
 807 Misc
 808 ----
 809 - [Rustdoc now allows you to specify `--crate-version` to have rustdoc include
 810   the version in the sidebar.][69494]
 811
 812 Compatibility Notes
 813 -------------------
 814 - [Rustc now correctly generates static libraries on Windows GNU targets with
 815   the `.a` extension, rather than the previous `.lib`.][70937]
 816 - [Removed the `-C no_integrated_as` flag from rustc.][70345]
 817 - [The `file_name` property in JSON output of macro errors now points the actual
 818   source file rather than the previous format of `<NAME macros>`.][70969]
 819   **Note:** this may not point to a file that actually exists on the user's system.
 820 - [The minimum required external LLVM version has been bumped to LLVM 8.][71147]
 821 - [`mem::{zeroed, uninitialised}` will now panic when used with types that do
 822   not allow zero initialization such as `NonZeroU8`.][66059] This was
 823   previously a warning.
 824 - [In 1.45.0 (the next release) converting a `f64` to `u32` using the `as`
 825   operator has been defined as a saturating operation.][71269] This was previously
 826   undefined behaviour, but you can use the `{f64, f32}::to_int_unchecked` methods to
 827   continue using the current behaviour, which may be desirable in rare performance
 828   sensitive situations.
 829
 830 Internal Only
 831 -------------
 832 These changes provide no direct user facing benefits, but represent significant
 833 improvements to the internals and overall performance of rustc and
 834 related tools.
 835
 836 - [dep_graph Avoid allocating a set on when the number reads are small.][69778]
 837 - [Replace big JS dict with JSON parsing.][71250]
 838
 839 [69373]: https://github.com/rust-lang/rust/pull/69373/
 840 [66059]: https://github.com/rust-lang/rust/pull/66059/
 841 [68191]: https://github.com/rust-lang/rust/pull/68191/
 842 [68899]: https://github.com/rust-lang/rust/pull/68899/
 843 [71147]: https://github.com/rust-lang/rust/pull/71147/
 844 [71250]: https://github.com/rust-lang/rust/pull/71250/
 845 [70937]: https://github.com/rust-lang/rust/pull/70937/
 846 [70969]: https://github.com/rust-lang/rust/pull/70969/
 847 [70632]: https://github.com/rust-lang/rust/pull/70632/
 848 [70281]: https://github.com/rust-lang/rust/pull/70281/
 849 [70345]: https://github.com/rust-lang/rust/pull/70345/
 850 [70048]: https://github.com/rust-lang/rust/pull/70048/
 851 [70081]: https://github.com/rust-lang/rust/pull/70081/
 852 [70156]: https://github.com/rust-lang/rust/pull/70156/
 853 [71269]: https://github.com/rust-lang/rust/pull/71269/
 854 [69838]: https://github.com/rust-lang/rust/pull/69838/
 855 [69929]: https://github.com/rust-lang/rust/pull/69929/
 856 [69661]: https://github.com/rust-lang/rust/pull/69661/
 857 [69778]: https://github.com/rust-lang/rust/pull/69778/
 858 [69494]: https://github.com/rust-lang/rust/pull/69494/
 859 [69403]: https://github.com/rust-lang/rust/pull/69403/
 860 [69033]: https://github.com/rust-lang/rust/pull/69033/
 861 [68692]: https://github.com/rust-lang/rust/pull/68692/
 862 [68334]: https://github.com/rust-lang/rust/pull/68334/
 863 [67502]: https://github.com/rust-lang/rust/pull/67502/
 864 [cargo/8062]: https://github.com/rust-lang/cargo/pull/8062/
 865 [`PathBuf::with_capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.with_capacity
 866 [`PathBuf::capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.capacity
 867 [`PathBuf::clear`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.clear
 868 [`PathBuf::reserve`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve
 869 [`PathBuf::reserve_exact`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve_exact
 870 [`PathBuf::shrink_to_fit`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.shrink_to_fit
 871 [`f32::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_int_unchecked
 872 [`f64::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_int_unchecked
 873 [`Layout::align_to`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.align_to
 874 [`Layout::pad_to_align`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.pad_to_align
 875 [`Layout::array`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.array
 876 [`Layout::extend`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.extend
 877
 878
 879 Version 1.43.1 (2020-05-07)
 880 ===========================
 881
 882 * [Updated openssl-src to 1.1.1g for CVE-2020-1967.][71430]
 883 * [Fixed the stabilization of AVX-512 features.][71473]
 884 * [Fixed `cargo package --list` not working with unpublished dependencies.][cargo/8151]
 885
 886 [71430]: https://github.com/rust-lang/rust/pull/71430
 887 [71473]: https://github.com/rust-lang/rust/issues/71473
 888 [cargo/8151]: https://github.com/rust-lang/cargo/issues/8151
 889
 890
 891 Version 1.43.0 (2020-04-23)
 892 ==========================
 893
 894 Language
 895 --------
 896 - [Fixed using binary operations with `&{number}` (e.g. `&1.0`) not having
 897   the type inferred correctly.][68129]
 898 - [Attributes such as `#[cfg()]` can now be used on `if` expressions.][69201]
 899
 900 **Syntax only changes**
 901 - [Allow `type Foo: Ord` syntactically.][69361]
 902 - [Fuse associated and extern items up to defaultness.][69194]
 903 - [Syntactically allow `self` in all `fn` contexts.][68764]
 904 - [Merge `fn` syntax + cleanup item parsing.][68728]
 905 - [`item` macro fragments can be interpolated into `trait`s, `impl`s, and `extern` blocks.][69366]
 906   For example, you may now write:
 907   ```rust
 908   macro_rules! mac_trait {
 909       ($i:item) => {
 910           trait T { $i }
 911       }
 912   }
 913   mac_trait! {
 914       fn foo() {}
 915   }
 916   ```
 917
 918 These are still rejected *semantically*, so you will likely receive an error but
 919 these changes can be seen and parsed by macros and
 920 conditional compilation.
 921
 922
 923 Compiler
 924 --------
 925 - [You can now pass multiple lint flags to rustc to override the previous
 926   flags.][67885] For example; `rustc -D unused -A unused-variables` denies
 927   everything in the `unused` lint group except `unused-variables` which
 928   is explicitly allowed. However, passing `rustc -A unused-variables -D unused` denies
 929   everything in the `unused` lint group **including** `unused-variables` since
 930   the allow flag is specified before the deny flag (and therefore overridden).
 931 - [rustc will now prefer your system MinGW libraries over its bundled libraries
 932   if they are available on `windows-gnu`.][67429]
 933 - [rustc now buffers errors/warnings printed in JSON.][69227]
 934
 935 Libraries
 936 ---------
 937 - [`Arc<[T; N]>`, `Box<[T; N]>`, and `Rc<[T; N]>`, now implement
 938   `TryFrom<Arc<[T]>>`,`TryFrom<Box<[T]>>`, and `TryFrom<Rc<[T]>>`
 939   respectively.][69538] **Note** These conversions are only available when `N`
 940   is `0..=32`.
 941 - [You can now use associated constants on floats and integers directly, rather
 942   than having to import the module.][68952] e.g. You can now write `u32::MAX` or
 943   `f32::NAN` with no imports.
 944 - [`u8::is_ascii` is now `const`.][68984]
 945 - [`String` now implements `AsMut<str>`.][68742]
 946 - [Added the `primitive` module to `std` and `core`.][67637] This module
 947   reexports Rust's primitive types. This is mainly useful in macros
 948   where you want avoid these types being shadowed.
 949 - [Relaxed some of the trait bounds on `HashMap` and `HashSet`.][67642]
 950 - [`string::FromUtf8Error` now implements `Clone + Eq`.][68738]
 951
 952 Stabilized APIs
 953 ---------------
 954 - [`Once::is_completed`]
 955 - [`f32::LOG10_2`]
 956 - [`f32::LOG2_10`]
 957 - [`f64::LOG10_2`]
 958 - [`f64::LOG2_10`]
 959 - [`iter::once_with`]
 960
 961 Cargo
 962 -----
 963 - [You can now set config `[profile]`s in your `.cargo/config`, or through
 964   your environment.][cargo/7823]
 965 - [Cargo will now set `CARGO_BIN_EXE_<name>` pointing to a binary's
 966   executable path when running integration tests or benchmarks.][cargo/7697]
 967   `<name>` is the name of your binary as-is e.g. If you wanted the executable
 968   path for a binary named `my-program`you would use `env!("CARGO_BIN_EXE_my-program")`.
 969
 970 Misc
 971 ----
 972 - [Certain checks in the `const_err` lint were deemed unrelated to const
 973   evaluation][69185], and have been moved to the `unconditional_panic` and
 974   `arithmetic_overflow` lints.
 975
 976 Compatibility Notes
 977 -------------------
 978
 979 - [Having trailing syntax in the `assert!` macro is now a hard error.][69548] This
 980   has been a warning since 1.36.0.
 981 - [Fixed `Self` not having the correctly inferred type.][69340] This incorrectly
 982   led to some instances being accepted, and now correctly emits a hard error.
 983
 984 [69340]: https://github.com/rust-lang/rust/pull/69340
 985
 986 Internal Only
 987 -------------
 988 These changes provide no direct user facing benefits, but represent significant
 989 improvements to the internals and overall performance of `rustc` and
 990 related tools.
 991
 992 - [All components are now built with `opt-level=3` instead of `2`.][67878]
 993 - [Improved how rustc generates drop code.][67332]
 994 - [Improved performance from `#[inline]`-ing certain hot functions.][69256]
 995 - [traits: preallocate 2 Vecs of known initial size][69022]
 996 - [Avoid exponential behaviour when relating types][68772]
 997 - [Skip `Drop` terminators for enum variants without drop glue][68943]
 998 - [Improve performance of coherence checks][68966]
 999 - [Deduplicate types in the generator witness][68672]
1000 - [Invert control in struct_lint_level.][68725]
1001
1002 [67332]: https://github.com/rust-lang/rust/pull/67332/
1003 [67429]: https://github.com/rust-lang/rust/pull/67429/
1004 [67637]: https://github.com/rust-lang/rust/pull/67637/
1005 [67642]: https://github.com/rust-lang/rust/pull/67642/
1006 [67878]: https://github.com/rust-lang/rust/pull/67878/
1007 [67885]: https://github.com/rust-lang/rust/pull/67885/
1008 [68129]: https://github.com/rust-lang/rust/pull/68129/
1009 [68672]: https://github.com/rust-lang/rust/pull/68672/
1010 [68725]: https://github.com/rust-lang/rust/pull/68725/
1011 [68728]: https://github.com/rust-lang/rust/pull/68728/
1012 [68738]: https://github.com/rust-lang/rust/pull/68738/
1013 [68742]: https://github.com/rust-lang/rust/pull/68742/
1014 [68764]: https://github.com/rust-lang/rust/pull/68764/
1015 [68772]: https://github.com/rust-lang/rust/pull/68772/
1016 [68943]: https://github.com/rust-lang/rust/pull/68943/
1017 [68952]: https://github.com/rust-lang/rust/pull/68952/
1018 [68966]: https://github.com/rust-lang/rust/pull/68966/
1019 [68984]: https://github.com/rust-lang/rust/pull/68984/
1020 [69022]: https://github.com/rust-lang/rust/pull/69022/
1021 [69185]: https://github.com/rust-lang/rust/pull/69185/
1022 [69194]: https://github.com/rust-lang/rust/pull/69194/
1023 [69201]: https://github.com/rust-lang/rust/pull/69201/
1024 [69227]: https://github.com/rust-lang/rust/pull/69227/
1025 [69548]: https://github.com/rust-lang/rust/pull/69548/
1026 [69256]: https://github.com/rust-lang/rust/pull/69256/
1027 [69361]: https://github.com/rust-lang/rust/pull/69361/
1028 [69366]: https://github.com/rust-lang/rust/pull/69366/
1029 [69538]: https://github.com/rust-lang/rust/pull/69538/
1030 [cargo/7823]: https://github.com/rust-lang/cargo/pull/7823
1031 [cargo/7697]: https://github.com/rust-lang/cargo/pull/7697
1032 [`Once::is_completed`]: https://doc.rust-lang.org/std/sync/struct.Once.html#method.is_completed
1033 [`f32::LOG10_2`]: https://doc.rust-lang.org/std/f32/consts/constant.LOG10_2.html
1034 [`f32::LOG2_10`]: https://doc.rust-lang.org/std/f32/consts/constant.LOG2_10.html
1035 [`f64::LOG10_2`]: https://doc.rust-lang.org/std/f64/consts/constant.LOG10_2.html
1036 [`f64::LOG2_10`]: https://doc.rust-lang.org/std/f64/consts/constant.LOG2_10.html
1037 [`iter::once_with`]: https://doc.rust-lang.org/std/iter/fn.once_with.html
1038
1039
1040 Version 1.42.0 (2020-03-12)
1041 ==========================
1042
1043 Language
1044 --------
1045 - [You can now use the slice pattern syntax with subslices.][67712] e.g.
1046   ```rust
1047   fn foo(words: &[&str]) {
1048       match words {
1049           ["Hello", "World", "!", ..] => println!("Hello World!"),
1050           ["Foo", "Bar", ..] => println!("Baz"),
1051           rest => println!("{:?}", rest),
1052       }
1053   }
1054   ```
1055 - [You can now use `#[repr(transparent)]` on univariant `enum`s.][68122] Meaning
1056   that you can create an enum that has the exact layout and ABI of the type
1057   it contains.
1058 - [There are some *syntax-only* changes:][67131]
1059    - `default` is syntactically allowed before items in `trait` definitions.
1060    - Items in `impl`s (i.e. `const`s, `type`s, and `fn`s) may syntactically
1061      leave out their bodies in favor of `;`.
1062    - Bounds on associated types in `impl`s are now syntactically allowed
1063      (e.g. `type Foo: Ord;`).
1064    - `...` (the C-variadic type) may occur syntactically directly as the type of
1065       any function parameter.
1066
1067   These are still rejected *semantically*, so you will likely receive an error
1068   but these changes can be seen and parsed by procedural macros and
1069   conditional compilation.
1070
1071 Compiler
1072 --------
1073 - [Added tier 2\* support for `armv7a-none-eabi`.][68253]
1074 - [Added tier 2 support for `riscv64gc-unknown-linux-gnu`.][68339]
1075 - [`Option::{expect,unwrap}` and
1076    `Result::{expect, expect_err, unwrap, unwrap_err}` now produce panic messages
1077    pointing to the location where they were called, rather than
1078    `core`'s internals. ][67887]
1079
1080 \* Refer to Rust's [platform support page][forge-platform-support] for more
1081 information on Rust's tiered platform support.
1082
1083 Libraries
1084 ---------
1085 - [`iter::Empty<T>` now implements `Send` and `Sync` for any `T`.][68348]
1086 - [`Pin::{map_unchecked, map_unchecked_mut}` no longer require the return type
1087    to implement `Sized`.][67935]
1088 - [`io::Cursor` now derives `PartialEq` and `Eq`.][67233]
1089 - [`Layout::new` is now `const`.][66254]
1090 - [Added Standard Library support for `riscv64gc-unknown-linux-gnu`.][66899]
1091
1092
1093 Stabilized APIs
1094 ---------------
1095 - [`CondVar::wait_while`]
1096 - [`CondVar::wait_timeout_while`]
1097 - [`DebugMap::key`]
1098 - [`DebugMap::value`]
1099 - [`ManuallyDrop::take`]
1100 - [`matches!`]
1101 - [`ptr::slice_from_raw_parts_mut`]
1102 - [`ptr::slice_from_raw_parts`]
1103
1104 Cargo
1105 -----
1106 - [You no longer need to include `extern crate proc_macro;` to be able to
1107   `use proc_macro;` in the `2018` edition.][cargo/7700]
1108
1109 Compatibility Notes
1110 -------------------
1111 - [`Error::description` has been deprecated, and its use will now produce a
1112   warning.][66919] It's recommended to use `Display`/`to_string` instead.
1113
1114 [68253]: https://github.com/rust-lang/rust/pull/68253/
1115 [68348]: https://github.com/rust-lang/rust/pull/68348/
1116 [67935]: https://github.com/rust-lang/rust/pull/67935/
1117 [68339]: https://github.com/rust-lang/rust/pull/68339/
1118 [68122]: https://github.com/rust-lang/rust/pull/68122/
1119 [67712]: https://github.com/rust-lang/rust/pull/67712/
1120 [67887]: https://github.com/rust-lang/rust/pull/67887/
1121 [67131]: https://github.com/rust-lang/rust/pull/67131/
1122 [67233]: https://github.com/rust-lang/rust/pull/67233/
1123 [66899]: https://github.com/rust-lang/rust/pull/66899/
1124 [66919]: https://github.com/rust-lang/rust/pull/66919/
1125 [66254]: https://github.com/rust-lang/rust/pull/66254/
1126 [cargo/7700]: https://github.com/rust-lang/cargo/pull/7700
1127 [`DebugMap::key`]: https://doc.rust-lang.org/stable/std/fmt/struct.DebugMap.html#method.key
1128 [`DebugMap::value`]: https://doc.rust-lang.org/stable/std/fmt/struct.DebugMap.html#method.value
1129 [`ManuallyDrop::take`]: https://doc.rust-lang.org/stable/std/mem/struct.ManuallyDrop.html#method.take
1130 [`matches!`]: https://doc.rust-lang.org/stable/std/macro.matches.html
1131 [`ptr::slice_from_raw_parts_mut`]: https://doc.rust-lang.org/stable/std/ptr/fn.slice_from_raw_parts_mut.html
1132 [`ptr::slice_from_raw_parts`]: https://doc.rust-lang.org/stable/std/ptr/fn.slice_from_raw_parts.html
1133 [`CondVar::wait_while`]: https://doc.rust-lang.org/stable/std/sync/struct.Condvar.html#method.wait_while
1134 [`CondVar::wait_timeout_while`]: https://doc.rust-lang.org/stable/std/sync/struct.Condvar.html#method.wait_timeout_while
1135
1136
1137 Version 1.41.1 (2020-02-27)
1138 ===========================
1139
1140 * [Always check types of static items][69145]
1141 * [Always check lifetime bounds of `Copy` impls][69145]
1142 * [Fix miscompilation in callers of `Layout::repeat`][69225]
1143
1144 [69225]: https://github.com/rust-lang/rust/issues/69225
1145 [69145]: https://github.com/rust-lang/rust/pull/69145
1146
1147
1148 Version 1.41.0 (2020-01-30)
1149 ===========================
1150
1151 Language
1152 --------
1153
1154 - [You can now pass type parameters to foreign items when implementing
1155   traits.][65879] E.g. You can now write `impl<T> From<Foo> for Vec<T> {}`.
1156 - [You can now arbitrarily nest receiver types in the `self` position.][64325] E.g. you can
1157   now write `fn foo(self: Box<Box<Self>>) {}`. Previously only `Self`, `&Self`,
1158   `&mut Self`, `Arc<Self>`, `Rc<Self>`, and `Box<Self>` were allowed.
1159 - [You can now use any valid identifier in a `format_args` macro.][66847]
1160   Previously identifiers starting with an underscore were not allowed.
1161 - [Visibility modifiers (e.g. `pub`) are now syntactically allowed on trait items and
1162   enum variants.][66183] These are still rejected semantically, but
1163   can be seen and parsed by procedural macros and conditional compilation.
1164
1165 Compiler
1166 --------
1167
1168 - [Rustc will now warn if you have unused loop `'label`s.][66325]
1169 - [Removed support for the `i686-unknown-dragonfly` target.][67255]
1170 - [Added tier 3 support\* for the `riscv64gc-unknown-linux-gnu` target.][66661]
1171 - [You can now pass an arguments file passing the `@path` syntax
1172   to rustc.][66172] Note that the format differs somewhat from what is
1173   found in other tooling; please see [the documentation][argfile-docs] for
1174   more information.
1175 - [You can now provide `--extern` flag without a path, indicating that it is
1176   available from the search path or specified with an `-L` flag.][64882]
1177
1178 \* Refer to Rust's [platform support page][forge-platform-support] for more
1179 information on Rust's tiered platform support.
1180
1181 [argfile-docs]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#path-load-command-line-flags-from-a-path
1182
1183 Libraries
1184 ---------
1185
1186 - [The `core::panic` module is now stable.][66771] It was already stable
1187   through `std`.
1188 - [`NonZero*` numerics now implement `From<NonZero*>` if it's a smaller integer
1189   width.][66277] E.g. `NonZeroU16` now implements `From<NonZeroU8>`.
1190 - [`MaybeUninit<T>` now implements `fmt::Debug`.][65013]
1191
1192 Stabilized APIs
1193 ---------------
1194
1195 - [`Result::map_or`]
1196 - [`Result::map_or_else`]
1197 - [`std::rc::Weak::weak_count`]
1198 - [`std::rc::Weak::strong_count`]
1199 - [`std::sync::Weak::weak_count`]
1200 - [`std::sync::Weak::strong_count`]
1201
1202 Cargo
1203 -----
1204
1205 - [Cargo will now document all the private items for binary crates
1206   by default.][cargo/7593]
1207 - [`cargo-install` will now reinstall the package if it detects that it is out
1208   of date.][cargo/7560]
1209 - [Cargo.lock now uses a more git friendly format that should help to reduce
1210   merge conflicts.][cargo/7579]
1211 - [You can now override specific dependencies's build settings][cargo/7591] E.g.
1212   `[profile.dev.package.image] opt-level = 2` sets the `image` crate's
1213   optimisation level to `2` for debug builds. You can also use
1214   `[profile.<profile>.build-override]` to override build scripts and
1215   their dependencies.
1216
1217 Misc
1218 ----
1219
1220 - [You can now specify `edition` in documentation code blocks to compile the block
1221   for that edition.][66238] E.g. `edition2018` tells rustdoc that the code sample
1222   should be compiled the 2018 edition of Rust.
1223 - [You can now provide custom themes to rustdoc with `--theme`, and check the
1224   current theme with `--check-theme`.][54733]
1225 - [You can use `#[cfg(doc)]` to compile an item when building documentation.][61351]
1226
1227 Compatibility Notes
1228 -------------------
1229
1230 - [As previously announced 1.41.0 will be the last tier 1 release for 32-bit
1231   Apple targets.][apple-32bit-drop] This means that the source code is still
1232   available to build, but the targets are no longer being tested and release
1233   binaries for those platforms will no longer be distributed by the Rust project.
1234   Please refer to the linked blog post for more information.
1235
1236 [54733]: https://github.com/rust-lang/rust/pull/54733/
1237 [61351]: https://github.com/rust-lang/rust/pull/61351/
1238 [67255]: https://github.com/rust-lang/rust/pull/67255/
1239 [66661]: https://github.com/rust-lang/rust/pull/66661/
1240 [66771]: https://github.com/rust-lang/rust/pull/66771/
1241 [66847]: https://github.com/rust-lang/rust/pull/66847/
1242 [66238]: https://github.com/rust-lang/rust/pull/66238/
1243 [66277]: https://github.com/rust-lang/rust/pull/66277/
1244 [66325]: https://github.com/rust-lang/rust/pull/66325/
1245 [66172]: https://github.com/rust-lang/rust/pull/66172/
1246 [66183]: https://github.com/rust-lang/rust/pull/66183/
1247 [65879]: https://github.com/rust-lang/rust/pull/65879/
1248 [65013]: https://github.com/rust-lang/rust/pull/65013/
1249 [64882]: https://github.com/rust-lang/rust/pull/64882/
1250 [64325]: https://github.com/rust-lang/rust/pull/64325/
1251 [cargo/7560]: https://github.com/rust-lang/cargo/pull/7560/
1252 [cargo/7579]: https://github.com/rust-lang/cargo/pull/7579/
1253 [cargo/7591]: https://github.com/rust-lang/cargo/pull/7591/
1254 [cargo/7593]: https://github.com/rust-lang/cargo/pull/7593/
1255 [`Result::map_or_else`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.map_or_else
1256 [`Result::map_or`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.map_or
1257 [`std::rc::Weak::weak_count`]: https://doc.rust-lang.org/std/rc/struct.Weak.html#method.weak_count
1258 [`std::rc::Weak::strong_count`]: https://doc.rust-lang.org/std/rc/struct.Weak.html#method.strong_count
1259 [`std::sync::Weak::weak_count`]: https://doc.rust-lang.org/std/sync/struct.Weak.html#method.weak_count
1260 [`std::sync::Weak::strong_count`]: https://doc.rust-lang.org/std/sync/struct.Weak.html#method.strong_count
1261 [apple-32bit-drop]: https://blog.rust-lang.org/2020/01/03/reducing-support-for-32-bit-apple-targets.html
1262
1263 Version 1.40.0 (2019-12-19)
1264 ===========================
1265
1266 Language
1267 --------
1268 - [You can now use tuple `struct`s and tuple `enum` variant's constructors in
1269   `const` contexts.][65188] e.g.
1270
1271   ```rust
1272   pub struct Point(i32, i32);
1273
1274   const ORIGIN: Point = {
1275       let constructor = Point;
1276
1277       constructor(0, 0)
1278   };
1279   ```
1280
1281 - [You can now mark `struct`s, `enum`s, and `enum` variants with the `#[non_exhaustive]` attribute to
1282   indicate that there may be variants or fields added in the future.][64639]
1283   For example this requires adding a wild-card branch (`_ => {}`) to any match
1284   statements on a non-exhaustive `enum`. [(RFC 2008)]
1285 - [You can now use function-like procedural macros in `extern` blocks and in
1286   type positions.][63931] e.g. `type Generated = macro!();`
1287 - [Function-like and attribute procedural macros can now emit
1288   `macro_rules!` items, so you can now have your macros generate macros.][64035]
1289 - [The `meta` pattern matcher in `macro_rules!` now correctly matches the modern
1290   attribute syntax.][63674] For example `(#[$m:meta])` now matches `#[attr]`,
1291   `#[attr{tokens}]`, `#[attr[tokens]]`, and `#[attr(tokens)]`.
1292
1293 Compiler
1294 --------
1295 - [Added tier 3 support\* for the
1296   `thumbv7neon-unknown-linux-musleabihf` target.][66103]
1297 - [Added tier 3 support for the
1298   `aarch64-unknown-none-softfloat` target.][64589]
1299 - [Added tier 3 support for the `mips64-unknown-linux-muslabi64`, and
1300   `mips64el-unknown-linux-muslabi64` targets.][65843]
1301
1302 \* Refer to Rust's [platform support page][forge-platform-support] for more
1303   information on Rust's tiered platform support.
1304
1305 Libraries
1306 ---------
1307 - [The `is_power_of_two` method on unsigned numeric types is now a `const` function.][65092]
1308
1309 Stabilized APIs
1310 ---------------
1311 - [`BTreeMap::get_key_value`]
1312 - [`HashMap::get_key_value`]
1313 - [`Option::as_deref_mut`]
1314 - [`Option::as_deref`]
1315 - [`Option::flatten`]
1316 - [`UdpSocket::peer_addr`]
1317 - [`f32::to_be_bytes`]
1318 - [`f32::to_le_bytes`]
1319 - [`f32::to_ne_bytes`]
1320 - [`f64::to_be_bytes`]
1321 - [`f64::to_le_bytes`]
1322 - [`f64::to_ne_bytes`]
1323 - [`f32::from_be_bytes`]
1324 - [`f32::from_le_bytes`]
1325 - [`f32::from_ne_bytes`]
1326 - [`f64::from_be_bytes`]
1327 - [`f64::from_le_bytes`]
1328 - [`f64::from_ne_bytes`]
1329 - [`mem::take`]
1330 - [`slice::repeat`]
1331 - [`todo!`]
1332
1333 Cargo
1334 -----
1335 - [Cargo will now always display warnings, rather than only on
1336   fresh builds.][cargo/7450]
1337 - [Feature flags (except `--all-features`) passed to a virtual workspace will
1338   now produce an error.][cargo/7507] Previously these flags were ignored.
1339 - [You can now publish `dev-dependencies` without including
1340   a `version`.][cargo/7333]
1341
1342 Misc
1343 ----
1344 - [You can now specify the `#[cfg(doctest)]` attribute to include an item only
1345   when running documentation tests with `rustdoc`.][63803]
1346
1347 Compatibility Notes
1348 -------------------
1349 - [As previously announced, any previous NLL warnings in the 2015 edition are
1350   now hard errors.][64221]
1351 - [The `include!` macro will now warn if it failed to include the
1352   entire file.][64284] The `include!` macro unintentionally only includes the
1353   first _expression_ in a file, and this can be unintuitive. This will become
1354   either a hard error in a future release, or the behavior may be fixed to include all expressions as expected.
1355 - [Using `#[inline]` on function prototypes and consts now emits a warning under
1356   `unused_attribute` lint.][65294] Using `#[inline]` anywhere else inside traits
1357   or `extern` blocks now correctly emits a hard error.
1358
1359 [65294]: https://github.com/rust-lang/rust/pull/65294/
1360 [66103]: https://github.com/rust-lang/rust/pull/66103/
1361 [65843]: https://github.com/rust-lang/rust/pull/65843/
1362 [65188]: https://github.com/rust-lang/rust/pull/65188/
1363 [65092]: https://github.com/rust-lang/rust/pull/65092/
1364 [64589]: https://github.com/rust-lang/rust/pull/64589/
1365 [64639]: https://github.com/rust-lang/rust/pull/64639/
1366 [64221]: https://github.com/rust-lang/rust/pull/64221/
1367 [64284]: https://github.com/rust-lang/rust/pull/64284/
1368 [63931]: https://github.com/rust-lang/rust/pull/63931/
1369 [64035]: https://github.com/rust-lang/rust/pull/64035/
1370 [63674]: https://github.com/rust-lang/rust/pull/63674/
1371 [63803]: https://github.com/rust-lang/rust/pull/63803/
1372 [cargo/7450]: https://github.com/rust-lang/cargo/pull/7450/
1373 [cargo/7507]: https://github.com/rust-lang/cargo/pull/7507/
1374 [cargo/7525]: https://github.com/rust-lang/cargo/pull/7525/
1375 [cargo/7333]: https://github.com/rust-lang/cargo/pull/7333/
1376 [(rfc 2008)]: https://rust-lang.github.io/rfcs/2008-non-exhaustive.html
1377 [`f32::to_be_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_be_bytes
1378 [`f32::to_le_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_le_bytes
1379 [`f32::to_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_ne_bytes
1380 [`f64::to_be_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_be_bytes
1381 [`f64::to_le_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_le_bytes
1382 [`f64::to_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_ne_bytes
1383 [`f32::from_be_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_be_bytes
1384 [`f32::from_le_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_le_bytes
1385 [`f32::from_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_ne_bytes
1386 [`f64::from_be_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_be_bytes
1387 [`f64::from_le_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_le_bytes
1388 [`f64::from_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_ne_bytes
1389 [`option::flatten`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.flatten
1390 [`option::as_deref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref
1391 [`option::as_deref_mut`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref_mut
1392 [`hashmap::get_key_value`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.get_key_value
1393 [`btreemap::get_key_value`]: https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.get_key_value
1394 [`slice::repeat`]: https://doc.rust-lang.org/std/primitive.slice.html#method.repeat
1395 [`mem::take`]: https://doc.rust-lang.org/std/mem/fn.take.html
1396 [`udpsocket::peer_addr`]: https://doc.rust-lang.org/std/net/struct.UdpSocket.html#method.peer_addr
1397 [`todo!`]: https://doc.rust-lang.org/std/macro.todo.html
1398
1399
1400 Version 1.39.0 (2019-11-07)
1401 ===========================
1402
1403 Language
1404 --------
1405 - [You can now create `async` functions and blocks with `async fn`, `async move {}`, and
1406   `async {}` respectively, and you can now call `.await` on async expressions.][63209]
1407 - [You can now use certain attributes on function, closure, and function pointer
1408   parameters.][64010] These attributes include `cfg`, `cfg_attr`, `allow`, `warn`,
1409   `deny`, `forbid` as well as inert helper attributes used by procedural macro
1410   attributes applied to items. e.g.
1411   ```rust
1412   fn len(
1413       #[cfg(windows)] slice: &[u16],
1414       #[cfg(not(windows))] slice: &[u8],
1415   ) -> usize {
1416       slice.len()
1417   }
1418   ```
1419 - [You can now take shared references to bind-by-move patterns in the `if` guards
1420   of `match` arms.][63118] e.g.
1421   ```rust
1422   fn main() {
1423       let array: Box<[u8; 4]> = Box::new([1, 2, 3, 4]);
1424
1425       match array {
1426           nums
1427   //      ---- `nums` is bound by move.
1428               if nums.iter().sum::<u8>() == 10
1429   //                 ^------ `.iter()` implicitly takes a reference to `nums`.
1430           => {
1431               drop(nums);
1432   //          ----------- Legal as `nums` was bound by move and so we have ownership.
1433           }
1434           _ => unreachable!(),
1435       }
1436   }
1437   ```
1438
1439
1440
1441 Compiler
1442 --------
1443 - [Added tier 3\* support for the `i686-unknown-uefi` target.][64334]
1444 - [Added tier 3 support for the `sparc64-unknown-openbsd` target.][63595]
1445 - [rustc will now trim code snippets in diagnostics to fit in your terminal.][63402]
1446   **Note** Cargo currently doesn't use this feature. Refer to
1447   [cargo#7315][cargo/7315] to track this feature's progress.
1448 - [You can now pass `--show-output` argument to test binaries to print the
1449   output of successful tests.][62600]
1450
1451
1452 \* Refer to Rust's [platform support page][forge-platform-support] for more
1453 information on Rust's tiered platform support.
1454
1455 Libraries
1456 ---------
1457 - [`Vec::new` and `String::new` are now `const` functions.][64028]
1458 - [`LinkedList::new` is now a `const` function.][63684]
1459 - [`str::len`, `[T]::len` and `str::as_bytes` are now `const` functions.][63770]
1460 - [The `abs`, `wrapping_abs`, and `overflowing_abs` numeric functions are
1461   now `const`.][63786]
1462
1463 Stabilized APIs
1464 ---------------
1465 - [`Pin::into_inner`]
1466 - [`Instant::checked_duration_since`]
1467 - [`Instant::saturating_duration_since`]
1468
1469 Cargo
1470 -----
1471 - [You can now publish git dependencies if supplied with a `version`.][cargo/7237]
1472 - [The `--all` flag has been renamed to `--workspace`.][cargo/7241] Using
1473   `--all` is now deprecated.
1474
1475 Misc
1476 ----
1477 - [You can now pass `-Clinker` to rustdoc to control the linker used
1478   for compiling doctests.][63834]
1479
1480 Compatibility Notes
1481 -------------------
1482 - [Code that was previously accepted by the old borrow checker, but rejected by
1483   the NLL borrow checker is now a hard error in Rust 2018.][63565] This was
1484   previously a warning, and will also become a hard error in the Rust 2015
1485   edition in the 1.40.0 release.
1486 - [`rustdoc` now requires `rustc` to be installed and in the same directory to
1487   run tests.][63827] This should improve performance when running a large
1488   amount of doctests.
1489 - [The `try!` macro will now issue a deprecation warning.][62672] It is
1490   recommended to use the `?` operator instead.
1491 - [`asinh(-0.0)` now correctly returns `-0.0`.][63698] Previously this
1492   returned `0.0`.
1493
1494 [62600]: https://github.com/rust-lang/rust/pull/62600/
1495 [62672]: https://github.com/rust-lang/rust/pull/62672/
1496 [63118]: https://github.com/rust-lang/rust/pull/63118/
1497 [63209]: https://github.com/rust-lang/rust/pull/63209/
1498 [63402]: https://github.com/rust-lang/rust/pull/63402/
1499 [63565]: https://github.com/rust-lang/rust/pull/63565/
1500 [63595]: https://github.com/rust-lang/rust/pull/63595/
1501 [63684]: https://github.com/rust-lang/rust/pull/63684/
1502 [63698]: https://github.com/rust-lang/rust/pull/63698/
1503 [63770]: https://github.com/rust-lang/rust/pull/63770/
1504 [63786]: https://github.com/rust-lang/rust/pull/63786/
1505 [63827]: https://github.com/rust-lang/rust/pull/63827/
1506 [63834]: https://github.com/rust-lang/rust/pull/63834/
1507 [63927]: https://github.com/rust-lang/rust/pull/63927/
1508 [63933]: https://github.com/rust-lang/rust/pull/63933/
1509 [63934]: https://github.com/rust-lang/rust/pull/63934/
1510 [63938]: https://github.com/rust-lang/rust/pull/63938/
1511 [63940]: https://github.com/rust-lang/rust/pull/63940/
1512 [63941]: https://github.com/rust-lang/rust/pull/63941/
1513 [63945]: https://github.com/rust-lang/rust/pull/63945/
1514 [64010]: https://github.com/rust-lang/rust/pull/64010/
1515 [64028]: https://github.com/rust-lang/rust/pull/64028/
1516 [64334]: https://github.com/rust-lang/rust/pull/64334/
1517 [cargo/7237]: https://github.com/rust-lang/cargo/pull/7237/
1518 [cargo/7241]: https://github.com/rust-lang/cargo/pull/7241/
1519 [cargo/7315]: https://github.com/rust-lang/cargo/pull/7315/
1520 [`Pin::into_inner`]: https://doc.rust-lang.org/std/pin/struct.Pin.html#method.into_inner
1521 [`Instant::checked_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_duration_since
1522 [`Instant::saturating_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.saturating_duration_since
1523
1524 Version 1.38.0 (2019-09-26)
1525 ==========================
1526
1527 Language
1528 --------
1529 - [The `#[global_allocator]` attribute can now be used in submodules.][62735]
1530 - [The `#[deprecated]` attribute can now be used on macros.][62042]
1531
1532 Compiler
1533 --------
1534 - [Added pipelined compilation support to `rustc`.][62766] This will
1535   improve compilation times in some cases. For further information please refer
1536   to the [_"Evaluating pipelined rustc compilation"_][pipeline-internals] thread.
1537 - [Added tier 3\* support for the `aarch64-uwp-windows-msvc`, `i686-uwp-windows-gnu`,
1538   `i686-uwp-windows-msvc`, `x86_64-uwp-windows-gnu`, and
1539   `x86_64-uwp-windows-msvc` targets.][60260]
1540 - [Added tier 3 support for the `armv7-unknown-linux-gnueabi` and
1541   `armv7-unknown-linux-musleabi` targets.][63107]
1542 - [Added tier 3 support for the `hexagon-unknown-linux-musl` target.][62814]
1543 - [Added tier 3 support for the `riscv32i-unknown-none-elf` target.][62784]
1544 - [Upgraded to LLVM 9.][62592]
1545
1546 \* Refer to Rust's [platform support page][forge-platform-support] for more
1547 information on Rust's tiered platform support.
1548
1549 Libraries
1550 ---------
1551 - [`ascii::EscapeDefault` now implements `Clone` and `Display`.][63421]
1552 - [Derive macros for prelude traits (e.g. `Clone`, `Debug`, `Hash`) are now
1553   available at the same path as the trait.][63056] (e.g. The `Clone` derive macro
1554   is available at `std::clone::Clone`). This also makes all built-in macros
1555   available in `std`/`core` root. e.g. `std::include_bytes!`.
1556 - [`str::Chars` now implements `Debug`.][63000]
1557 - [`slice::{concat, connect, join}` now accepts `&[T]` in addition to `&T`.][62528]
1558 - [`*const T` and `*mut T` now implement `marker::Unpin`.][62583]
1559 - [`Arc<[T]>` and `Rc<[T]>` now implement `FromIterator<T>`.][61953]
1560 - [Added euclidean remainder and division operations (`div_euclid`,
1561   `rem_euclid`) to all numeric primitives.][61884] Additionally `checked`,
1562   `overflowing`, and `wrapping` versions are available for all
1563   integer primitives.
1564 - [`thread::AccessError` now implements `Clone`, `Copy`, `Eq`, `Error`, and
1565   `PartialEq`.][61491]
1566 - [`iter::{StepBy, Peekable, Take}` now implement `DoubleEndedIterator`.][61457]
1567
1568 Stabilized APIs
1569 ---------------
1570 - [`<*const T>::cast`]
1571 - [`<*mut T>::cast`]
1572 - [`Duration::as_secs_f32`]
1573 - [`Duration::as_secs_f64`]
1574 - [`Duration::div_f32`]
1575 - [`Duration::div_f64`]
1576 - [`Duration::from_secs_f32`]
1577 - [`Duration::from_secs_f64`]
1578 - [`Duration::mul_f32`]
1579 - [`Duration::mul_f64`]
1580 - [`any::type_name`]
1581
1582 Cargo
1583 -----
1584 - [Added pipelined compilation support to `cargo`.][cargo/7143]
1585 - [You can now pass the `--features` option multiple times to enable
1586   multiple features.][cargo/7084]
1587
1588 Misc
1589 ----
1590 - [`rustc` will now warn about some incorrect uses of
1591   `mem::{uninitialized, zeroed}` that are known to cause undefined behaviour.][63346]
1592
1593 Compatibility Notes
1594 -------------------
1595 - The [`x86_64-unknown-uefi` platform can not be built][62785] with rustc
1596   1.38.0.
1597 - The [`armv7-unknown-linux-gnueabihf` platform is known to have
1598   issues][62896] with certain crates such as libc.
1599
1600 [60260]: https://github.com/rust-lang/rust/pull/60260/
1601 [61457]: https://github.com/rust-lang/rust/pull/61457/
1602 [61491]: https://github.com/rust-lang/rust/pull/61491/
1603 [61884]: https://github.com/rust-lang/rust/pull/61884/
1604 [61953]: https://github.com/rust-lang/rust/pull/61953/
1605 [62042]: https://github.com/rust-lang/rust/pull/62042/
1606 [62528]: https://github.com/rust-lang/rust/pull/62528/
1607 [62583]: https://github.com/rust-lang/rust/pull/62583/
1608 [62735]: https://github.com/rust-lang/rust/pull/62735/
1609 [62766]: https://github.com/rust-lang/rust/pull/62766/
1610 [62784]: https://github.com/rust-lang/rust/pull/62784/
1611 [62592]: https://github.com/rust-lang/rust/pull/62592/
1612 [62785]: https://github.com/rust-lang/rust/issues/62785/
1613 [62814]: https://github.com/rust-lang/rust/pull/62814/
1614 [62896]: https://github.com/rust-lang/rust/issues/62896/
1615 [63000]: https://github.com/rust-lang/rust/pull/63000/
1616 [63056]: https://github.com/rust-lang/rust/pull/63056/
1617 [63107]: https://github.com/rust-lang/rust/pull/63107/
1618 [63346]: https://github.com/rust-lang/rust/pull/63346/
1619 [63421]: https://github.com/rust-lang/rust/pull/63421/
1620 [cargo/7084]: https://github.com/rust-lang/cargo/pull/7084/
1621 [cargo/7143]: https://github.com/rust-lang/cargo/pull/7143/
1622 [`<*const T>::cast`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.cast
1623 [`<*mut T>::cast`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.cast
1624 [`Duration::as_secs_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs_f32
1625 [`Duration::as_secs_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs_f64
1626 [`Duration::div_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_f32
1627 [`Duration::div_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_f64
1628 [`Duration::from_secs_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_secs_f32
1629 [`Duration::from_secs_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_secs_f64
1630 [`Duration::mul_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f32
1631 [`Duration::mul_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f64
1632 [`any::type_name`]: https://doc.rust-lang.org/std/any/fn.type_name.html
1633 [forge-platform-support]: https://forge.rust-lang.org/release/platform-support.html
1634 [pipeline-internals]: https://internals.rust-lang.org/t/evaluating-pipelined-rustc-compilation/10199
1635
1636 Version 1.37.0 (2019-08-15)
1637 ==========================
1638
1639 Language
1640 --------
1641 - `#[must_use]` will now warn if the type is contained in a [tuple][61100],
1642   [`Box`][62228], or an [array][62235] and unused.
1643 - [You can now use the `cfg` and `cfg_attr` attributes on
1644   generic parameters.][61547]
1645 - [You can now use enum variants through type alias.][61682] e.g. You can
1646   write the following:
1647   ```rust
1648   type MyOption = Option<u8>;
1649
1650   fn increment_or_zero(x: MyOption) -> u8 {
1651       match x {
1652           MyOption::Some(y) => y + 1,
1653           MyOption::None => 0,
1654       }
1655   }
1656   ```
1657 - [You can now use `_` as an identifier for consts.][61347] e.g. You can write
1658   `const _: u32 = 5;`.
1659 - [You can now use `#[repr(align(X)]` on enums.][61229]
1660 - [The  `?` Kleene macro operator is now available in the
1661   2015 edition.][60932]
1662
1663 Compiler
1664 --------
1665 - [You can now enable Profile-Guided Optimization with the `-C profile-generate`
1666   and `-C profile-use` flags.][61268] For more information on how to use profile
1667   guided optimization, please refer to the [rustc book][rustc-book-pgo].
1668 - [The `rust-lldb` wrapper script should now work again.][61827]
1669
1670 Libraries
1671 ---------
1672 - [`mem::MaybeUninit<T>` is now ABI-compatible with `T`.][61802]
1673
1674 Stabilized APIs
1675 ---------------
1676 - [`BufReader::buffer`]
1677 - [`BufWriter::buffer`]
1678 - [`Cell::from_mut`]
1679 - [`Cell<[T]>::as_slice_of_cells`][`Cell<slice>::as_slice_of_cells`]
1680 - [`DoubleEndedIterator::nth_back`]
1681 - [`Option::xor`]
1682 - [`Wrapping::reverse_bits`]
1683 - [`i128::reverse_bits`]
1684 - [`i16::reverse_bits`]
1685 - [`i32::reverse_bits`]
1686 - [`i64::reverse_bits`]
1687 - [`i8::reverse_bits`]
1688 - [`isize::reverse_bits`]
1689 - [`slice::copy_within`]
1690 - [`u128::reverse_bits`]
1691 - [`u16::reverse_bits`]
1692 - [`u32::reverse_bits`]
1693 - [`u64::reverse_bits`]
1694 - [`u8::reverse_bits`]
1695 - [`usize::reverse_bits`]
1696
1697 Cargo
1698 -----
1699 - [`Cargo.lock` files are now included by default when publishing executable crates
1700   with executables.][cargo/7026]
1701 - [You can now specify `default-run="foo"` in `[package]` to specify the
1702   default executable to use for `cargo run`.][cargo/7056]
1703
1704 Misc
1705 ----
1706
1707 Compatibility Notes
1708 -------------------
1709 - [Using `...` for inclusive range patterns will now warn by default.][61342]
1710   Please transition your code to using the `..=` syntax for inclusive
1711   ranges instead.
1712 - [Using a trait object without the `dyn` will now warn by default.][61203]
1713   Please transition your code to use `dyn Trait` for trait objects instead.
1714
1715 [62228]: https://github.com/rust-lang/rust/pull/62228/
1716 [62235]: https://github.com/rust-lang/rust/pull/62235/
1717 [61802]: https://github.com/rust-lang/rust/pull/61802/
1718 [61827]: https://github.com/rust-lang/rust/pull/61827/
1719 [61547]: https://github.com/rust-lang/rust/pull/61547/
1720 [61682]: https://github.com/rust-lang/rust/pull/61682/
1721 [61268]: https://github.com/rust-lang/rust/pull/61268/
1722 [61342]: https://github.com/rust-lang/rust/pull/61342/
1723 [61347]: https://github.com/rust-lang/rust/pull/61347/
1724 [61100]: https://github.com/rust-lang/rust/pull/61100/
1725 [61203]: https://github.com/rust-lang/rust/pull/61203/
1726 [61229]: https://github.com/rust-lang/rust/pull/61229/
1727 [60932]: https://github.com/rust-lang/rust/pull/60932/
1728 [cargo/7026]: https://github.com/rust-lang/cargo/pull/7026/
1729 [cargo/7056]: https://github.com/rust-lang/cargo/pull/7056/
1730 [`BufReader::buffer`]: https://doc.rust-lang.org/std/io/struct.BufReader.html#method.buffer
1731 [`BufWriter::buffer`]: https://doc.rust-lang.org/std/io/struct.BufWriter.html#method.buffer
1732 [`Cell::from_mut`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.from_mut
1733 [`Cell<slice>::as_slice_of_cells`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.as_slice_of_cells
1734 [`DoubleEndedIterator::nth_back`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.nth_back
1735 [`Option::xor`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.xor
1736 [`RefCell::try_borrow_unguarded`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.try_borrow_unguarded
1737 [`Wrapping::reverse_bits`]: https://doc.rust-lang.org/std/num/struct.Wrapping.html#method.reverse_bits
1738 [`i128::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i128.html#method.reverse_bits
1739 [`i16::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i16.html#method.reverse_bits
1740 [`i32::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i32.html#method.reverse_bits
1741 [`i64::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i64.html#method.reverse_bits
1742 [`i8::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i8.html#method.reverse_bits
1743 [`isize::reverse_bits`]: https://doc.rust-lang.org/std/primitive.isize.html#method.reverse_bits
1744 [`slice::copy_within`]: https://doc.rust-lang.org/std/primitive.slice.html#method.copy_within
1745 [`u128::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u128.html#method.reverse_bits
1746 [`u16::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u16.html#method.reverse_bits
1747 [`u32::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u32.html#method.reverse_bits
1748 [`u64::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u64.html#method.reverse_bits
1749 [`u8::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u8.html#method.reverse_bits
1750 [`usize::reverse_bits`]: https://doc.rust-lang.org/std/primitive.usize.html#method.reverse_bits
1751 [rustc-book-pgo]: https://doc.rust-lang.org/rustc/profile-guided-optimization.html
1752
1753
1754 Version 1.36.0 (2019-07-04)
1755 ==========================
1756
1757 Language
1758 --------
1759 - [Non-Lexical Lifetimes are now enabled on the 2015 edition.][59114]
1760 - [The order of traits in trait objects no longer affects the semantics of that
1761   object.][59445] e.g. `dyn Send + fmt::Debug` is now equivalent to
1762   `dyn fmt::Debug + Send`, where this was previously not the case.
1763
1764 Libraries
1765 ---------
1766 - [`HashMap`'s implementation has been replaced with `hashbrown::HashMap` implementation.][58623]
1767 - [`TryFromSliceError` now implements `From<Infallible>`.][60318]
1768 - [`mem::needs_drop` is now available as a const fn.][60364]
1769 - [`alloc::Layout::from_size_align_unchecked` is now available as a const fn.][60370]
1770 - [`String` now implements `BorrowMut<str>`.][60404]
1771 - [`io::Cursor` now implements `Default`.][60234]
1772 - [Both `NonNull::{dangling, cast}` are now const fns.][60244]
1773 - [The `alloc` crate is now stable.][59675] `alloc` allows you to use a subset
1774   of `std` (e.g. `Vec`, `Box`, `Arc`) in `#![no_std]` environments if the
1775   environment has access to heap memory allocation.
1776 - [`String` now implements `From<&String>`.][59825]
1777 - [You can now pass multiple arguments to the `dbg!` macro.][59826] `dbg!` will
1778   return a tuple of each argument when there is multiple arguments.
1779 - [`Result::{is_err, is_ok}` are now `#[must_use]` and will produce a warning if
1780   not used.][59648]
1781
1782 Stabilized APIs
1783 ---------------
1784 - [`VecDeque::rotate_left`]
1785 - [`VecDeque::rotate_right`]
1786 - [`Iterator::copied`]
1787 - [`io::IoSlice`]
1788 - [`io::IoSliceMut`]
1789 - [`Read::read_vectored`]
1790 - [`Write::write_vectored`]
1791 - [`str::as_mut_ptr`]
1792 - [`mem::MaybeUninit`]
1793 - [`pointer::align_offset`]
1794 - [`future::Future`]
1795 - [`task::Context`]
1796 - [`task::RawWaker`]
1797 - [`task::RawWakerVTable`]
1798 - [`task::Waker`]
1799 - [`task::Poll`]
1800
1801 Cargo
1802 -----
1803 - [Cargo will now produce an error if you attempt to use the name of a required dependency as a feature.][cargo/6860]
1804 - [You can now pass the `--offline` flag to run cargo without accessing the network.][cargo/6934]
1805
1806 You can find further change's in [Cargo's 1.36.0 release notes][cargo-1-36-0].
1807
1808 Clippy
1809 ------
1810 There have been numerous additions and fixes to clippy, see [Clippy's 1.36.0 release notes][clippy-1-36-0] for more details.
1811
1812 Misc
1813 ----
1814
1815 Compatibility Notes
1816 -------------------
1817 - With the stabilisation of `mem::MaybeUninit`, `mem::uninitialized` use is no
1818   longer recommended, and will be deprecated in 1.39.0.
1819
1820 [60318]: https://github.com/rust-lang/rust/pull/60318/
1821 [60364]: https://github.com/rust-lang/rust/pull/60364/
1822 [60370]: https://github.com/rust-lang/rust/pull/60370/
1823 [60404]: https://github.com/rust-lang/rust/pull/60404/
1824 [60234]: https://github.com/rust-lang/rust/pull/60234/
1825 [60244]: https://github.com/rust-lang/rust/pull/60244/
1826 [58623]: https://github.com/rust-lang/rust/pull/58623/
1827 [59648]: https://github.com/rust-lang/rust/pull/59648/
1828 [59675]: https://github.com/rust-lang/rust/pull/59675/
1829 [59825]: https://github.com/rust-lang/rust/pull/59825/
1830 [59826]: https://github.com/rust-lang/rust/pull/59826/
1831 [59445]: https://github.com/rust-lang/rust/pull/59445/
1832 [59114]: https://github.com/rust-lang/rust/pull/59114/
1833 [cargo/6860]: https://github.com/rust-lang/cargo/pull/6860/
1834 [cargo/6934]: https://github.com/rust-lang/cargo/pull/6934/
1835 [`VecDeque::rotate_left`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.rotate_left
1836 [`VecDeque::rotate_right`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.rotate_right
1837 [`Iterator::copied`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.copied
1838 [`io::IoSlice`]: https://doc.rust-lang.org/std/io/struct.IoSlice.html
1839 [`io::IoSliceMut`]: https://doc.rust-lang.org/std/io/struct.IoSliceMut.html
1840 [`Read::read_vectored`]: https://doc.rust-lang.org/std/io/trait.Read.html#method.read_vectored
1841 [`Write::write_vectored`]: https://doc.rust-lang.org/std/io/trait.Write.html#method.write_vectored
1842 [`str::as_mut_ptr`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_mut_ptr
1843 [`mem::MaybeUninit`]: https://doc.rust-lang.org/std/mem/union.MaybeUninit.html
1844 [`pointer::align_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.align_offset
1845 [`future::Future`]: https://doc.rust-lang.org/std/future/trait.Future.html
1846 [`task::Context`]: https://doc.rust-lang.org/beta/std/task/struct.Context.html
1847 [`task::RawWaker`]: https://doc.rust-lang.org/beta/std/task/struct.RawWaker.html
1848 [`task::RawWakerVTable`]: https://doc.rust-lang.org/beta/std/task/struct.RawWakerVTable.html
1849 [`task::Waker`]: https://doc.rust-lang.org/beta/std/task/struct.Waker.html
1850 [`task::Poll`]: https://doc.rust-lang.org/beta/std/task/enum.Poll.html
1851 [clippy-1-36-0]: https://github.com/rust-lang/rust-clippy/blob/master/CHANGELOG.md#rust-136
1852 [cargo-1-36-0]: https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-136-2019-07-04
1853
1854
1855 Version 1.35.0 (2019-05-23)
1856 ==========================
1857
1858 Language
1859 --------
1860 - [`FnOnce`, `FnMut`, and the `Fn` traits are now implemented for `Box<FnOnce>`,
1861   `Box<FnMut>`, and `Box<Fn>` respectively.][59500]
1862 - [You can now coerce closures into unsafe function pointers.][59580] e.g.
1863   ```rust
1864   unsafe fn call_unsafe(func: unsafe fn()) {
1865       func()
1866   }
1867
1868   pub fn main() {
1869       unsafe { call_unsafe(|| {}); }
1870   }
1871   ```
1872
1873
1874 Compiler
1875 --------
1876 - [Added the `armv6-unknown-freebsd-gnueabihf` and
1877   `armv7-unknown-freebsd-gnueabihf` targets.][58080]
1878 - [Added the `wasm32-unknown-wasi` target.][59464]
1879
1880
1881 Libraries
1882 ---------
1883 - [`Thread` will now show its ID in `Debug` output.][59460]
1884 - [`StdinLock`, `StdoutLock`, and `StderrLock` now implement `AsRawFd`.][59512]
1885 - [`alloc::System` now implements `Default`.][59451]
1886 - [Expanded `Debug` output (`{:#?}`) for structs now has a trailing comma on the
1887   last field.][59076]
1888 - [`char::{ToLowercase, ToUppercase}` now
1889   implement `ExactSizeIterator`.][58778]
1890 - [All `NonZero` numeric types now implement `FromStr`.][58717]
1891 - [Removed the `Read` trait bounds
1892   on the `BufReader::{get_ref, get_mut, into_inner}` methods.][58423]
1893 - [You can now call the `dbg!` macro without any parameters to print the file
1894   and line where it is called.][57847]
1895 - [In place ASCII case conversions are now up to 4× faster.][59283]
1896   e.g. `str::make_ascii_lowercase`
1897 - [`hash_map::{OccupiedEntry, VacantEntry}` now implement `Sync`
1898   and `Send`.][58369]
1899
1900 Stabilized APIs
1901 ---------------
1902 - [`f32::copysign`]
1903 - [`f64::copysign`]
1904 - [`RefCell::replace_with`]
1905 - [`RefCell::map_split`]
1906 - [`ptr::hash`]
1907 - [`Range::contains`]
1908 - [`RangeFrom::contains`]
1909 - [`RangeTo::contains`]
1910 - [`RangeInclusive::contains`]
1911 - [`RangeToInclusive::contains`]
1912 - [`Option::copied`]
1913
1914 Cargo
1915 -----
1916 - [You can now set `cargo:rustc-cdylib-link-arg` at build time to pass custom
1917   linker arguments when building a `cdylib`.][cargo/6298] Its usage is highly
1918   platform specific.
1919
1920 Misc
1921 ----
1922 - [The Rust toolchain is now available natively for musl based distros.][58575]
1923
1924 [59460]: https://github.com/rust-lang/rust/pull/59460/
1925 [59464]: https://github.com/rust-lang/rust/pull/59464/
1926 [59500]: https://github.com/rust-lang/rust/pull/59500/
1927 [59512]: https://github.com/rust-lang/rust/pull/59512/
1928 [59580]: https://github.com/rust-lang/rust/pull/59580/
1929 [59283]: https://github.com/rust-lang/rust/pull/59283/
1930 [59451]: https://github.com/rust-lang/rust/pull/59451/
1931 [59076]: https://github.com/rust-lang/rust/pull/59076/
1932 [58778]: https://github.com/rust-lang/rust/pull/58778/
1933 [58717]: https://github.com/rust-lang/rust/pull/58717/
1934 [58369]: https://github.com/rust-lang/rust/pull/58369/
1935 [58423]: https://github.com/rust-lang/rust/pull/58423/
1936 [58080]: https://github.com/rust-lang/rust/pull/58080/
1937 [57847]: https://github.com/rust-lang/rust/pull/57847/
1938 [58575]: https://github.com/rust-lang/rust/pull/58575
1939 [cargo/6298]: https://github.com/rust-lang/cargo/pull/6298/
1940 [`f32::copysign`]: https://doc.rust-lang.org/stable/std/primitive.f32.html#method.copysign
1941 [`f64::copysign`]: https://doc.rust-lang.org/stable/std/primitive.f64.html#method.copysign
1942 [`RefCell::replace_with`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.replace_with
1943 [`RefCell::map_split`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.map_split
1944 [`ptr::hash`]: https://doc.rust-lang.org/stable/std/ptr/fn.hash.html
1945 [`Range::contains`]: https://doc.rust-lang.org/std/ops/struct.Range.html#method.contains
1946 [`RangeFrom::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeFrom.html#method.contains
1947 [`RangeTo::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeTo.html#method.contains
1948 [`RangeInclusive::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.contains
1949 [`RangeToInclusive::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeToInclusive.html#method.contains
1950 [`Option::copied`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.copied
1951
1952 Version 1.34.2 (2019-05-14)
1953 ===========================
1954
1955 * [Destabilize the `Error::type_id` function due to a security
1956    vulnerability][60785] ([CVE-2019-12083])
1957
1958 [60785]: https://github.com/rust-lang/rust/pull/60785
1959 [CVE-2019-12083]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12083
1960
1961 Version 1.34.1 (2019-04-25)
1962 ===========================
1963
1964 * [Fix false positives for the `redundant_closure` Clippy lint][clippy/3821]
1965 * [Fix false positives for the `missing_const_for_fn` Clippy lint][clippy/3844]
1966 * [Fix Clippy panic when checking some macros][clippy/3805]
1967
1968 [clippy/3821]: https://github.com/rust-lang/rust-clippy/pull/3821
1969 [clippy/3844]: https://github.com/rust-lang/rust-clippy/pull/3844
1970 [clippy/3805]: https://github.com/rust-lang/rust-clippy/pull/3805
1971
1972 Version 1.34.0 (2019-04-11)
1973 ==========================
1974
1975 Language
1976 --------
1977 - [You can now use `#[deprecated = "reason"]`][58166] as a shorthand for
1978   `#[deprecated(note = "reason")]`. This was previously allowed by mistake
1979   but had no effect.
1980 - [You can now accept token streams in `#[attr()]`,`#[attr[]]`, and
1981   `#[attr{}]` procedural macros.][57367]
1982 - [You can now write `extern crate self as foo;`][57407] to import your
1983   crate's root into the extern prelude.
1984
1985
1986 Compiler
1987 --------
1988 - [You can now target `riscv64imac-unknown-none-elf` and
1989   `riscv64gc-unknown-none-elf`.][58406]
1990 - [You can now enable linker plugin LTO optimisations with
1991   `-C linker-plugin-lto`.][58057] This allows rustc to compile your Rust code
1992   into LLVM bitcode allowing LLVM to perform LTO optimisations across C/C++ FFI
1993   boundaries.
1994 - [You can now target `powerpc64-unknown-freebsd`.][57809]
1995
1996
1997 Libraries
1998 ---------
1999 - [The trait bounds have been removed on some of `HashMap<K, V, S>`'s and
2000   `HashSet<T, S>`'s basic methods.][58370] Most notably you no longer require
2001   the `Hash` trait to create an iterator.
2002 - [The `Ord` trait bounds have been removed on some of `BinaryHeap<T>`'s basic
2003   methods.][58421] Most notably you no longer require the `Ord` trait to create
2004   an iterator.
2005 - [The methods `overflowing_neg` and `wrapping_neg` are now `const` functions
2006   for all numeric types.][58044]
2007 - [Indexing a `str` is now generic over all types that
2008   implement `SliceIndex<str>`.][57604]
2009 - [`str::trim`, `str::trim_matches`, `str::trim_{start, end}`, and
2010   `str::trim_{start, end}_matches` are now `#[must_use]`][57106] and will
2011   produce a warning if their returning type is unused.
2012 - [The methods `checked_pow`, `saturating_pow`, `wrapping_pow`, and
2013   `overflowing_pow` are now available for all numeric types.][57873] These are
2014   equivalent to methods such as `wrapping_add` for the `pow` operation.
2015
2016
2017 Stabilized APIs
2018 ---------------
2019
2020 #### std & core
2021 * [`Any::type_id`]
2022 * [`Error::type_id`]
2023 * [`atomic::AtomicI16`]
2024 * [`atomic::AtomicI32`]
2025 * [`atomic::AtomicI64`]
2026 * [`atomic::AtomicI8`]
2027 * [`atomic::AtomicU16`]
2028 * [`atomic::AtomicU32`]
2029 * [`atomic::AtomicU64`]
2030 * [`atomic::AtomicU8`]
2031 * [`convert::Infallible`]
2032 * [`convert::TryFrom`]
2033 * [`convert::TryInto`]
2034 * [`iter::from_fn`]
2035 * [`iter::successors`]
2036 * [`num::NonZeroI128`]
2037 * [`num::NonZeroI16`]
2038 * [`num::NonZeroI32`]
2039 * [`num::NonZeroI64`]
2040 * [`num::NonZeroI8`]
2041 * [`num::NonZeroIsize`]
2042 * [`slice::sort_by_cached_key`]
2043 * [`str::escape_debug`]
2044 * [`str::escape_default`]
2045 * [`str::escape_unicode`]
2046 * [`str::split_ascii_whitespace`]
2047
2048 #### std
2049 * [`Instant::checked_add`]
2050 * [`Instant::checked_sub`]
2051 * [`SystemTime::checked_add`]
2052 * [`SystemTime::checked_sub`]
2053
2054 Cargo
2055 -----
2056 - [You can now use alternative registries to crates.io.][cargo/6654]
2057
2058 Misc
2059 ----
2060 - [You can now use the `?` operator in your documentation tests without manually
2061   adding `fn main() -> Result<(), _> {}`.][56470]
2062
2063 Compatibility Notes
2064 -------------------
2065 - [`Command::before_exec` is being replaced by the unsafe method
2066   `Command::pre_exec`][58059] and will be deprecated with Rust 1.37.0.
2067 - [Use of `ATOMIC_{BOOL, ISIZE, USIZE}_INIT` is now deprecated][57425] as you
2068   can now use `const` functions in `static` variables.
2069
2070 [58370]: https://github.com/rust-lang/rust/pull/58370/
2071 [58406]: https://github.com/rust-lang/rust/pull/58406/
2072 [58421]: https://github.com/rust-lang/rust/pull/58421/
2073 [58166]: https://github.com/rust-lang/rust/pull/58166/
2074 [58044]: https://github.com/rust-lang/rust/pull/58044/
2075 [58057]: https://github.com/rust-lang/rust/pull/58057/
2076 [58059]: https://github.com/rust-lang/rust/pull/58059/
2077 [57809]: https://github.com/rust-lang/rust/pull/57809/
2078 [57873]: https://github.com/rust-lang/rust/pull/57873/
2079 [57604]: https://github.com/rust-lang/rust/pull/57604/
2080 [57367]: https://github.com/rust-lang/rust/pull/57367/
2081 [57407]: https://github.com/rust-lang/rust/pull/57407/
2082 [57425]: https://github.com/rust-lang/rust/pull/57425/
2083 [57106]: https://github.com/rust-lang/rust/pull/57106/
2084 [56470]: https://github.com/rust-lang/rust/pull/56470/
2085 [cargo/6654]: https://github.com/rust-lang/cargo/pull/6654/
2086 [`Any::type_id`]: https://doc.rust-lang.org/std/any/trait.Any.html#tymethod.type_id
2087 [`Error::type_id`]: https://doc.rust-lang.org/std/error/trait.Error.html#method.type_id
2088 [`atomic::AtomicI16`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicI16.html
2089 [`atomic::AtomicI32`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicI32.html
2090 [`atomic::AtomicI64`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicI64.html
2091 [`atomic::AtomicI8`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicI8.html
2092 [`atomic::AtomicU16`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU16.html
2093 [`atomic::AtomicU32`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU32.html
2094 [`atomic::AtomicU64`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU64.html
2095 [`atomic::AtomicU8`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU8.html
2096 [`convert::Infallible`]: https://doc.rust-lang.org/std/convert/enum.Infallible.html
2097 [`convert::TryFrom`]: https://doc.rust-lang.org/std/convert/trait.TryFrom.html
2098 [`convert::TryInto`]: https://doc.rust-lang.org/std/convert/trait.TryInto.html
2099 [`iter::from_fn`]: https://doc.rust-lang.org/std/iter/fn.from_fn.html
2100 [`iter::successors`]: https://doc.rust-lang.org/std/iter/fn.successors.html
2101 [`num::NonZeroI128`]: https://doc.rust-lang.org/std/num/struct.NonZeroI128.html
2102 [`num::NonZeroI16`]: https://doc.rust-lang.org/std/num/struct.NonZeroI16.html
2103 [`num::NonZeroI32`]: https://doc.rust-lang.org/std/num/struct.NonZeroI32.html
2104 [`num::NonZeroI64`]: https://doc.rust-lang.org/std/num/struct.NonZeroI64.html
2105 [`num::NonZeroI8`]: https://doc.rust-lang.org/std/num/struct.NonZeroI8.html
2106 [`num::NonZeroIsize`]: https://doc.rust-lang.org/std/num/struct.NonZeroIsize.html
2107 [`slice::sort_by_cached_key`]: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_by_cached_key
2108 [`str::escape_debug`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_debug
2109 [`str::escape_default`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_default
2110 [`str::escape_unicode`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_unicode
2111 [`str::split_ascii_whitespace`]: https://doc.rust-lang.org/std/primitive.str.html#method.split_ascii_whitespace
2112 [`Instant::checked_add`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_add
2113 [`Instant::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_sub
2114 [`SystemTime::checked_add`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_add
2115 [`SystemTime::checked_sub`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_sub
2116
2117
2118 Version 1.33.0 (2019-02-28)
2119 ==========================
2120
2121 Language
2122 --------
2123 - [You can now use the `cfg(target_vendor)` attribute.][57465] E.g.
2124   `#[cfg(target_vendor="apple")] fn main() { println!("Hello Apple!"); }`
2125 - [Integer patterns such as in a match expression can now be exhaustive.][56362]
2126   E.g. You can have match statement on a `u8` that covers `0..=255` and
2127   you would no longer be required to have a `_ => unreachable!()` case.
2128 - [You can now have multiple patterns in `if let` and `while let`
2129   expressions.][57532] You can do this with the same syntax as a `match`
2130   expression. E.g.
2131   ```rust
2132   enum Creature {
2133       Crab(String),
2134       Lobster(String),
2135       Person(String),
2136   }
2137
2138   fn main() {
2139       let state = Creature::Crab("Ferris");
2140
2141       if let Creature::Crab(name) | Creature::Person(name) = state {
2142           println!("This creature's name is: {}", name);
2143       }
2144   }
2145   ```
2146 - [You can now have irrefutable `if let` and `while let` patterns.][57535] Using
2147   this feature will by default produce a warning as this behaviour can be
2148   unintuitive. E.g. `if let _ = 5 {}`
2149 - [You can now use `let` bindings, assignments, expression statements,
2150   and irrefutable pattern destructuring in const functions.][57175]
2151 - [You can now call unsafe const functions.][57067] E.g.
2152   ```rust
2153   const unsafe fn foo() -> i32 { 5 }
2154   const fn bar() -> i32 {
2155       unsafe { foo() }
2156   }
2157   ```
2158 - [You can now specify multiple attributes in a `cfg_attr` attribute.][57332]
2159   E.g. `#[cfg_attr(all(), must_use, optimize)]`
2160 - [You can now specify a specific alignment with the `#[repr(packed)]`
2161   attribute.][57049] E.g. `#[repr(packed(2))] struct Foo(i16, i32);` is a struct
2162   with an alignment of 2 bytes and a size of 6 bytes.
2163 - [You can now import an item from a module as an `_`.][56303] This allows you to
2164   import a trait's impls, and not have the name in the namespace. E.g.
2165   ```rust
2166   use std::io::Read as _;
2167
2168   // Allowed as there is only one `Read` in the module.
2169   pub trait Read {}
2170   ```
2171 - [You may now use `Rc`, `Arc`, and `Pin` as method receivers][56805].
2172
2173 Compiler
2174 --------
2175 - [You can now set a linker flavor for `rustc` with the `-Clinker-flavor`
2176   command line argument.][56351]
2177 - [The minimum required LLVM version has been bumped to 6.0.][56642]
2178 - [Added support for the PowerPC64 architecture on FreeBSD.][57615]
2179 - [The `x86_64-fortanix-unknown-sgx` target support has been upgraded to
2180   tier 2 support.][57130] Visit the [platform support][platform-support] page for
2181   information on Rust's platform support.
2182 - [Added support for the `thumbv7neon-linux-androideabi` and
2183   `thumbv7neon-unknown-linux-gnueabihf` targets.][56947]
2184 - [Added support for the `x86_64-unknown-uefi` target.][56769]
2185
2186 Libraries
2187 ---------
2188 - [The methods `overflowing_{add, sub, mul, shl, shr}` are now `const`
2189   functions for all numeric types.][57566]
2190 - [The methods `rotate_left`, `rotate_right`, and `wrapping_{add, sub, mul, shl, shr}`
2191   are now `const` functions for all numeric types.][57105]
2192 - [The methods `is_positive` and `is_negative` are now `const` functions for
2193   all signed numeric types.][57105]
2194 - [The `get` method for all `NonZero` types is now `const`.][57167]
2195 - [The methods `count_ones`, `count_zeros`, `leading_zeros`, `trailing_zeros`,
2196   `swap_bytes`, `from_be`, `from_le`, `to_be`, `to_le` are now `const` for all
2197   numeric types.][57234]
2198 - [`Ipv4Addr::new` is now a `const` function][57234]
2199
2200 Stabilized APIs
2201 ---------------
2202 - [`unix::FileExt::read_exact_at`]
2203 - [`unix::FileExt::write_all_at`]
2204 - [`Option::transpose`]
2205 - [`Result::transpose`]
2206 - [`convert::identity`]
2207 - [`pin::Pin`]
2208 - [`marker::Unpin`]
2209 - [`marker::PhantomPinned`]
2210 - [`Vec::resize_with`]
2211 - [`VecDeque::resize_with`]
2212 - [`Duration::as_millis`]
2213 - [`Duration::as_micros`]
2214 - [`Duration::as_nanos`]
2215
2216
2217 Cargo
2218 -----
2219 - [You can now publish crates that require a feature flag to compile with
2220   `cargo publish --features` or `cargo publish --all-features`.][cargo/6453]
2221 - [Cargo should now rebuild a crate if a file was modified during the initial
2222   build.][cargo/6484]
2223
2224 Compatibility Notes
2225 -------------------
2226 - The methods `str::{trim_left, trim_right, trim_left_matches, trim_right_matches}`
2227   are now deprecated in the standard library, and their usage will now produce a warning.
2228   Please use the `str::{trim_start, trim_end, trim_start_matches, trim_end_matches}`
2229   methods instead.
2230 - The `Error::cause` method has been deprecated in favor of `Error::source` which supports
2231   downcasting.
2232 - [Libtest no longer creates a new thread for each test when
2233   `--test-threads=1`.  It also runs the tests in deterministic order][56243]
2234
2235 [55982]: https://github.com/rust-lang/rust/pull/55982/
2236 [56243]: https://github.com/rust-lang/rust/pull/56243
2237 [56303]: https://github.com/rust-lang/rust/pull/56303/
2238 [56351]: https://github.com/rust-lang/rust/pull/56351/
2239 [56362]: https://github.com/rust-lang/rust/pull/56362
2240 [56642]: https://github.com/rust-lang/rust/pull/56642/
2241 [56769]: https://github.com/rust-lang/rust/pull/56769/
2242 [56805]: https://github.com/rust-lang/rust/pull/56805
2243 [56947]: https://github.com/rust-lang/rust/pull/56947/
2244 [57049]: https://github.com/rust-lang/rust/pull/57049/
2245 [57067]: https://github.com/rust-lang/rust/pull/57067/
2246 [57105]: https://github.com/rust-lang/rust/pull/57105
2247 [57130]: https://github.com/rust-lang/rust/pull/57130/
2248 [57167]: https://github.com/rust-lang/rust/pull/57167/
2249 [57175]: https://github.com/rust-lang/rust/pull/57175/
2250 [57234]: https://github.com/rust-lang/rust/pull/57234/
2251 [57332]: https://github.com/rust-lang/rust/pull/57332/
2252 [57465]: https://github.com/rust-lang/rust/pull/57465/
2253 [57532]: https://github.com/rust-lang/rust/pull/57532/
2254 [57535]: https://github.com/rust-lang/rust/pull/57535/
2255 [57566]: https://github.com/rust-lang/rust/pull/57566/
2256 [57615]: https://github.com/rust-lang/rust/pull/57615/
2257 [cargo/6453]: https://github.com/rust-lang/cargo/pull/6453/
2258 [cargo/6484]: https://github.com/rust-lang/cargo/pull/6484/
2259 [`unix::FileExt::read_exact_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.read_exact_at
2260 [`unix::FileExt::write_all_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.write_all_at
2261 [`Option::transpose`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.transpose
2262 [`Result::transpose`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.transpose
2263 [`convert::identity`]: https://doc.rust-lang.org/std/convert/fn.identity.html
2264 [`pin::Pin`]: https://doc.rust-lang.org/std/pin/struct.Pin.html
2265 [`marker::Unpin`]: https://doc.rust-lang.org/stable/std/marker/trait.Unpin.html
2266 [`marker::PhantomPinned`]: https://doc.rust-lang.org/nightly/std/marker/struct.PhantomPinned.html
2267 [`Vec::resize_with`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.resize_with
2268 [`VecDeque::resize_with`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.resize_with
2269 [`Duration::as_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_millis
2270 [`Duration::as_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_micros
2271 [`Duration::as_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_nanos
2272 [platform-support]: https://forge.rust-lang.org/platform-support.html
2273
2274 Version 1.32.0 (2019-01-17)
2275 ==========================
2276
2277 Language
2278 --------
2279 #### 2018 edition
2280 - [You can now use the `?` operator in macro definitions.][56245] The `?`
2281   operator allows you to specify zero or one repetitions similar to the `*` and
2282   `+` operators.
2283 - [Module paths with no leading keyword like `super`, `self`, or `crate`, will
2284   now always resolve to the item (`enum`, `struct`, etc.) available in the
2285   module if present, before resolving to a external crate or an item the prelude.][56759]
2286   E.g.
2287   ```rust
2288   enum Color { Red, Green, Blue }
2289
2290   use Color::*;
2291   ```
2292
2293 #### All editions
2294 - [You can now match against `PhantomData<T>` types.][55837]
2295 - [You can now match against literals in macros with the `literal`
2296   specifier.][56072] This will match against a literal of any type.
2297   E.g. `1`, `'A'`, `"Hello World"`
2298 - [Self can now be used as a constructor and pattern for unit and tuple structs.][56365] E.g.
2299   ```rust
2300   struct Point(i32, i32);
2301
2302   impl Point {
2303       pub fn new(x: i32, y: i32) -> Self {
2304           Self(x, y)
2305       }
2306
2307       pub fn is_origin(&self) -> bool {
2308           match self {
2309               Self(0, 0) => true,
2310               _ => false,
2311           }
2312       }
2313   }
2314   ```
2315 - [Self can also now be used in type definitions.][56366] E.g.
2316   ```rust
2317   enum List<T>
2318   where
2319       Self: PartialOrd<Self> // can write `Self` instead of `List<T>`
2320   {
2321       Nil,
2322       Cons(T, Box<Self>) // likewise here
2323   }
2324   ```
2325 - [You can now mark traits with `#[must_use]`.][55663] This provides a warning if
2326   a `impl Trait` or `dyn Trait` is returned and unused in the program.
2327
2328 Compiler
2329 --------
2330 - [The default allocator has changed from jemalloc to the default allocator on
2331   your system.][55238] The compiler itself on Linux & macOS will still use
2332   jemalloc, but programs compiled with it will use the system allocator.
2333 - [Added the `aarch64-pc-windows-msvc` target.][55702]
2334
2335 Libraries
2336 ---------
2337 - [`PathBuf` now implements `FromStr`.][55148]
2338 - [`Box<[T]>` now implements `FromIterator<T>`.][55843]
2339 - [The `dbg!` macro has been stabilized.][56395] This macro enables you to
2340   easily debug expressions in your rust program. E.g.
2341   ```rust
2342   let a = 2;
2343   let b = dbg!(a * 2) + 1;
2344   //      ^-- prints: [src/main.rs:4] a * 2 = 4
2345   assert_eq!(b, 5);
2346   ```
2347
2348 The following APIs are now `const` functions and can be used in a
2349 `const` context.
2350
2351 - [`Cell::as_ptr`]
2352 - [`UnsafeCell::get`]
2353 - [`char::is_ascii`]
2354 - [`iter::empty`]
2355 - [`ManuallyDrop::new`]
2356 - [`ManuallyDrop::into_inner`]
2357 - [`RangeInclusive::start`]
2358 - [`RangeInclusive::end`]
2359 - [`NonNull::as_ptr`]
2360 - [`slice::as_ptr`]
2361 - [`str::as_ptr`]
2362 - [`Duration::as_secs`]
2363 - [`Duration::subsec_millis`]
2364 - [`Duration::subsec_micros`]
2365 - [`Duration::subsec_nanos`]
2366 - [`CStr::as_ptr`]
2367 - [`Ipv4Addr::is_unspecified`]
2368 - [`Ipv6Addr::new`]
2369 - [`Ipv6Addr::octets`]
2370
2371 Stabilized APIs
2372 ---------------
2373 - [`i8::to_be_bytes`]
2374 - [`i8::to_le_bytes`]
2375 - [`i8::to_ne_bytes`]
2376 - [`i8::from_be_bytes`]
2377 - [`i8::from_le_bytes`]
2378 - [`i8::from_ne_bytes`]
2379 - [`i16::to_be_bytes`]
2380 - [`i16::to_le_bytes`]
2381 - [`i16::to_ne_bytes`]
2382 - [`i16::from_be_bytes`]
2383 - [`i16::from_le_bytes`]
2384 - [`i16::from_ne_bytes`]
2385 - [`i32::to_be_bytes`]
2386 - [`i32::to_le_bytes`]
2387 - [`i32::to_ne_bytes`]
2388 - [`i32::from_be_bytes`]
2389 - [`i32::from_le_bytes`]
2390 - [`i32::from_ne_bytes`]
2391 - [`i64::to_be_bytes`]
2392 - [`i64::to_le_bytes`]
2393 - [`i64::to_ne_bytes`]
2394 - [`i64::from_be_bytes`]
2395 - [`i64::from_le_bytes`]
2396 - [`i64::from_ne_bytes`]
2397 - [`i128::to_be_bytes`]
2398 - [`i128::to_le_bytes`]
2399 - [`i128::to_ne_bytes`]
2400 - [`i128::from_be_bytes`]
2401 - [`i128::from_le_bytes`]
2402 - [`i128::from_ne_bytes`]
2403 - [`isize::to_be_bytes`]
2404 - [`isize::to_le_bytes`]
2405 - [`isize::to_ne_bytes`]
2406 - [`isize::from_be_bytes`]
2407 - [`isize::from_le_bytes`]
2408 - [`isize::from_ne_bytes`]
2409 - [`u8::to_be_bytes`]
2410 - [`u8::to_le_bytes`]
2411 - [`u8::to_ne_bytes`]
2412 - [`u8::from_be_bytes`]
2413 - [`u8::from_le_bytes`]
2414 - [`u8::from_ne_bytes`]
2415 - [`u16::to_be_bytes`]
2416 - [`u16::to_le_bytes`]
2417 - [`u16::to_ne_bytes`]
2418 - [`u16::from_be_bytes`]
2419 - [`u16::from_le_bytes`]
2420 - [`u16::from_ne_bytes`]
2421 - [`u32::to_be_bytes`]
2422 - [`u32::to_le_bytes`]
2423 - [`u32::to_ne_bytes`]
2424 - [`u32::from_be_bytes`]
2425 - [`u32::from_le_bytes`]
2426 - [`u32::from_ne_bytes`]
2427 - [`u64::to_be_bytes`]
2428 - [`u64::to_le_bytes`]
2429 - [`u64::to_ne_bytes`]
2430 - [`u64::from_be_bytes`]
2431 - [`u64::from_le_bytes`]
2432 - [`u64::from_ne_bytes`]
2433 - [`u128::to_be_bytes`]
2434 - [`u128::to_le_bytes`]
2435 - [`u128::to_ne_bytes`]
2436 - [`u128::from_be_bytes`]
2437 - [`u128::from_le_bytes`]
2438 - [`u128::from_ne_bytes`]
2439 - [`usize::to_be_bytes`]
2440 - [`usize::to_le_bytes`]
2441 - [`usize::to_ne_bytes`]
2442 - [`usize::from_be_bytes`]
2443 - [`usize::from_le_bytes`]
2444 - [`usize::from_ne_bytes`]
2445
2446 Cargo
2447 -----
2448 - [You can now run `cargo c` as an alias for `cargo check`.][cargo/6218]
2449 - [Usernames are now allowed in alt registry URLs.][cargo/6242]
2450
2451 Misc
2452 ----
2453 - [`libproc_macro` has been added to the `rust-src` distribution.][55280]
2454
2455 Compatibility Notes
2456 -------------------
2457 - [The argument types for AVX's
2458   `_mm256_stream_si256`, `_mm256_stream_pd`, `_mm256_stream_ps`][55610] have
2459   been changed from `*const` to `*mut` as the previous implementation
2460   was unsound.
2461
2462
2463 [55148]: https://github.com/rust-lang/rust/pull/55148/
2464 [55238]: https://github.com/rust-lang/rust/pull/55238/
2465 [55280]: https://github.com/rust-lang/rust/pull/55280/
2466 [55610]: https://github.com/rust-lang/rust/pull/55610/
2467 [55663]: https://github.com/rust-lang/rust/pull/55663/
2468 [55702]: https://github.com/rust-lang/rust/pull/55702/
2469 [55837]: https://github.com/rust-lang/rust/pull/55837/
2470 [55843]: https://github.com/rust-lang/rust/pull/55843/
2471 [56072]: https://github.com/rust-lang/rust/pull/56072/
2472 [56245]: https://github.com/rust-lang/rust/pull/56245/
2473 [56365]: https://github.com/rust-lang/rust/pull/56365/
2474 [56366]: https://github.com/rust-lang/rust/pull/56366/
2475 [56395]: https://github.com/rust-lang/rust/pull/56395/
2476 [56759]: https://github.com/rust-lang/rust/pull/56759/
2477 [cargo/6218]: https://github.com/rust-lang/cargo/pull/6218/
2478 [cargo/6242]: https://github.com/rust-lang/cargo/pull/6242/
2479 [`CStr::as_ptr`]: https://doc.rust-lang.org/std/ffi/struct.CStr.html#method.as_ptr
2480 [`Cell::as_ptr`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.as_ptr
2481 [`Duration::as_secs`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs
2482 [`Duration::subsec_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_micros
2483 [`Duration::subsec_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_millis
2484 [`Duration::subsec_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_nanos
2485 [`Ipv4Addr::is_unspecified`]: https://doc.rust-lang.org/std/net/struct.Ipv4Addr.html#method.is_unspecified
2486 [`Ipv6Addr::new`]: https://doc.rust-lang.org/std/net/struct.Ipv6Addr.html#method.new
2487 [`Ipv6Addr::octets`]: https://doc.rust-lang.org/std/net/struct.Ipv6Addr.html#method.octets
2488 [`ManuallyDrop::into_inner`]: https://doc.rust-lang.org/std/mem/struct.ManuallyDrop.html#method.into_inner
2489 [`ManuallyDrop::new`]: https://doc.rust-lang.org/std/mem/struct.ManuallyDrop.html#method.new
2490 [`NonNull::as_ptr`]: https://doc.rust-lang.org/std/ptr/struct.NonNull.html#method.as_ptr
2491 [`RangeInclusive::end`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.end
2492 [`RangeInclusive::start`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.start
2493 [`UnsafeCell::get`]: https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.get
2494 [`slice::as_ptr`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr
2495 [`char::is_ascii`]: https://doc.rust-lang.org/std/primitive.char.html#method.is_ascii
2496 [`i128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_be_bytes
2497 [`i128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_le_bytes
2498 [`i128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_ne_bytes
2499 [`i128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_be_bytes
2500 [`i128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_le_bytes
2501 [`i128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_ne_bytes
2502 [`i16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_be_bytes
2503 [`i16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_le_bytes
2504 [`i16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_ne_bytes
2505 [`i16::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_be_bytes
2506 [`i16::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_le_bytes
2507 [`i16::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_ne_bytes
2508 [`i32::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_be_bytes
2509 [`i32::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_le_bytes
2510 [`i32::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_ne_bytes
2511 [`i32::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_be_bytes
2512 [`i32::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_le_bytes
2513 [`i32::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_ne_bytes
2514 [`i64::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_be_bytes
2515 [`i64::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_le_bytes
2516 [`i64::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_ne_bytes
2517 [`i64::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_be_bytes
2518 [`i64::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_le_bytes
2519 [`i64::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_ne_bytes
2520 [`i8::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_be_bytes
2521 [`i8::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_le_bytes
2522 [`i8::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_ne_bytes
2523 [`i8::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_be_bytes
2524 [`i8::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_le_bytes
2525 [`i8::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_ne_bytes
2526 [`isize::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_be_bytes
2527 [`isize::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_le_bytes
2528 [`isize::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_ne_bytes
2529 [`isize::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_be_bytes
2530 [`isize::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_le_bytes
2531 [`isize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_ne_bytes
2532 [`iter::empty`]: https://doc.rust-lang.org/std/iter/fn.empty.html
2533 [`str::as_ptr`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_ptr
2534 [`u128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_be_bytes
2535 [`u128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_le_bytes
2536 [`u128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_ne_bytes
2537 [`u128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_be_bytes
2538 [`u128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_le_bytes
2539 [`u128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_ne_bytes
2540 [`u16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_be_bytes
2541 [`u16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_le_bytes
2542 [`u16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_ne_bytes
2543 [`u16::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_be_bytes
2544 [`u16::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_le_bytes
2545 [`u16::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_ne_bytes
2546 [`u32::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_be_bytes
2547 [`u32::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_le_bytes
2548 [`u32::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_ne_bytes
2549 [`u32::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_be_bytes
2550 [`u32::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_le_bytes
2551 [`u32::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_ne_bytes
2552 [`u64::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_be_bytes
2553 [`u64::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_le_bytes
2554 [`u64::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_ne_bytes
2555 [`u64::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_be_bytes
2556 [`u64::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_le_bytes
2557 [`u64::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_ne_bytes
2558 [`u8::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_be_bytes
2559 [`u8::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_le_bytes
2560 [`u8::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_ne_bytes
2561 [`u8::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_be_bytes
2562 [`u8::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_le_bytes
2563 [`u8::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_ne_bytes
2564 [`usize::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_be_bytes
2565 [`usize::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_le_bytes
2566 [`usize::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_ne_bytes
2567 [`usize::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_be_bytes
2568 [`usize::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_le_bytes
2569 [`usize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_ne_bytes
2570
2571
2572 Version 1.31.1 (2018-12-20)
2573 ===========================
2574
2575 - [Fix Rust failing to build on `powerpc-unknown-netbsd`][56562]
2576 - [Fix broken go-to-definition in RLS][rls/1171]
2577 - [Fix infinite loop on hover in RLS][rls/1170]
2578
2579 [56562]: https://github.com/rust-lang/rust/pull/56562
2580 [rls/1171]: https://github.com/rust-lang/rls/issues/1171
2581 [rls/1170]: https://github.com/rust-lang/rls/pull/1170
2582
2583 Version 1.31.0 (2018-12-06)
2584 ==========================
2585
2586 Language
2587 --------
2588 - 🎉 [This version marks the release of the 2018 edition of Rust.][54057] 🎉
2589 - [New lifetime elision rules now allow for eliding lifetimes in functions and
2590   impl headers.][54778] E.g. `impl<'a> Reader for BufReader<'a> {}` can now be
2591   `impl Reader for BufReader<'_> {}`. Lifetimes are still required to be defined
2592   in structs.
2593 - [You can now define and use `const` functions.][54835] These are currently
2594   a strict minimal subset of the [const fn RFC][RFC-911]. Refer to the
2595   [language reference][const-reference] for what exactly is available.
2596 - [You can now use tool lints, which allow you to scope lints from external
2597   tools using attributes.][54870] E.g. `#[allow(clippy::filter_map)]`.
2598 - [`#[no_mangle]` and `#[export_name]` attributes can now be located anywhere in
2599   a crate, not just in exported functions.][54451]
2600 - [You can now use parentheses in pattern matches.][54497]
2601
2602 Compiler
2603 --------
2604 - [Updated musl to 1.1.20][54430]
2605
2606 Libraries
2607 ---------
2608 - [You can now convert `num::NonZero*` types to their raw equivalents using the
2609   `From` trait.][54240] E.g. `u8` now implements `From<NonZeroU8>`.
2610 - [You can now convert a `&Option<T>` into `Option<&T>` and `&mut Option<T>`
2611   into `Option<&mut T>` using the `From` trait.][53218]
2612 - [You can now multiply (`*`) a `time::Duration` by a `u32`.][52813]
2613
2614
2615 Stabilized APIs
2616 ---------------
2617 - [`slice::align_to`]
2618 - [`slice::align_to_mut`]
2619 - [`slice::chunks_exact`]
2620 - [`slice::chunks_exact_mut`]
2621 - [`slice::rchunks`]
2622 - [`slice::rchunks_mut`]
2623 - [`slice::rchunks_exact`]
2624 - [`slice::rchunks_exact_mut`]
2625 - [`Option::replace`]
2626
2627 Cargo
2628 -----
2629 - [Cargo will now download crates in parallel using HTTP/2.][cargo/6005]
2630 - [You can now rename packages in your Cargo.toml][cargo/6319] We have a guide
2631   on [how to use the `package` key in your dependencies.][cargo-rename-reference]
2632
2633 [52813]: https://github.com/rust-lang/rust/pull/52813/
2634 [53218]: https://github.com/rust-lang/rust/pull/53218/
2635 [53555]: https://github.com/rust-lang/rust/issues/53555/
2636 [54057]: https://github.com/rust-lang/rust/pull/54057/
2637 [54240]: https://github.com/rust-lang/rust/pull/54240/
2638 [54430]: https://github.com/rust-lang/rust/pull/54430/
2639 [54451]: https://github.com/rust-lang/rust/pull/54451/
2640 [54497]: https://github.com/rust-lang/rust/pull/54497/
2641 [54778]: https://github.com/rust-lang/rust/pull/54778/
2642 [54835]: https://github.com/rust-lang/rust/pull/54835/
2643 [54870]: https://github.com/rust-lang/rust/pull/54870/
2644 [RFC-911]: https://github.com/rust-lang/rfcs/pull/911
2645 [`Option::replace`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.replace
2646 [`slice::align_to_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.align_to_mut
2647 [`slice::align_to`]: https://doc.rust-lang.org/std/primitive.slice.html#method.align_to
2648 [`slice::chunks_exact_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.chunks_exact_mut
2649 [`slice::chunks_exact`]: https://doc.rust-lang.org/std/primitive.slice.html#method.chunks_exact
2650 [`slice::rchunks_exact_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_mut
2651 [`slice::rchunks_exact`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_exact
2652 [`slice::rchunks_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_mut
2653 [`slice::rchunks`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks
2654 [cargo/6005]: https://github.com/rust-lang/cargo/pull/6005/
2655 [cargo/6319]: https://github.com/rust-lang/cargo/pull/6319/
2656 [cargo-rename-reference]: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#renaming-dependencies-in-cargotoml
2657 [const-reference]: https://doc.rust-lang.org/reference/items/functions.html#const-functions
2658
2659 Version 1.30.1 (2018-11-08)
2660 ===========================
2661
2662 - [Fixed overflow ICE in rustdoc][54199]
2663 - [Cap Cargo progress bar width at 60 in MSYS terminals][cargo/6122]
2664
2665 [54199]: https://github.com/rust-lang/rust/pull/54199
2666 [cargo/6122]: https://github.com/rust-lang/cargo/pull/6122
2667
2668 Version 1.30.0 (2018-10-25)
2669 ==========================
2670
2671 Language
2672 --------
2673 - [Procedural macros are now available.][52081] These kinds of macros allow for
2674   more powerful code generation. There is a [new chapter available][proc-macros]
2675   in the Rust Programming Language book that goes further in depth.
2676 - [You can now use keywords as identifiers using the raw identifiers
2677   syntax (`r#`),][53236] e.g. `let r#for = true;`
2678 - [Using anonymous parameters in traits is now deprecated with a warning and
2679   will be a hard error in the 2018 edition.][53272]
2680 - [You can now use `crate` in paths.][54404] This allows you to refer to the
2681   crate root in the path, e.g. `use crate::foo;` refers to `foo` in `src/lib.rs`.
2682 - [Using a external crate no longer requires being prefixed with `::`.][54404]
2683   Previously, using a external crate in a module without a use statement
2684   required `let json = ::serde_json::from_str(foo);` but can now be written
2685   as `let json = serde_json::from_str(foo);`.
2686 - [You can now apply the `#[used]` attribute to static items to prevent the
2687   compiler from optimising them away, even if they appear to be unused,][51363]
2688   e.g. `#[used] static FOO: u32 = 1;`
2689 - [You can now import and reexport macros from other crates with the `use`
2690   syntax.][50911] Macros exported with `#[macro_export]` are now placed into
2691   the root module of the crate. If your macro relies on calling other local
2692   macros, it is recommended to export with the
2693   `#[macro_export(local_inner_macros)]` attribute so users won't have to import
2694   those macros.
2695 - [You can now catch visibility keywords (e.g. `pub`, `pub(crate)`) in macros
2696   using the `vis` specifier.][53370]
2697 - [Non-macro attributes now allow all forms of literals, not just
2698   strings.][53044] Previously, you would write `#[attr("true")]`, and you can now
2699   write `#[attr(true)]`.
2700 - [You can now specify a function to handle a panic in the Rust runtime with the
2701   `#[panic_handler]` attribute.][51366]
2702
2703 Compiler
2704 --------
2705 - [Added the `riscv32imc-unknown-none-elf` target.][53822]
2706 - [Added the `aarch64-unknown-netbsd` target][53165]
2707 - [Upgraded to LLVM 8.][53611]
2708
2709 Libraries
2710 ---------
2711 - [`ManuallyDrop` now allows the inner type to be unsized.][53033]
2712
2713 Stabilized APIs
2714 ---------------
2715 - [`Ipv4Addr::BROADCAST`]
2716 - [`Ipv4Addr::LOCALHOST`]
2717 - [`Ipv4Addr::UNSPECIFIED`]
2718 - [`Ipv6Addr::LOCALHOST`]
2719 - [`Ipv6Addr::UNSPECIFIED`]
2720 - [`Iterator::find_map`]
2721
2722   The following methods are replacement methods for `trim_left`, `trim_right`,
2723   `trim_left_matches`, and `trim_right_matches`, which will be deprecated
2724   in 1.33.0:
2725 - [`str::trim_end_matches`]
2726 - [`str::trim_end`]
2727 - [`str::trim_start_matches`]
2728 - [`str::trim_start`]
2729
2730 Cargo
2731 ----
2732 - [`cargo run` doesn't require specifying a package in workspaces.][cargo/5877]
2733 - [`cargo doc` now supports `--message-format=json`.][cargo/5878] This is
2734   equivalent to calling `rustdoc --error-format=json`.
2735 - [Cargo will now provide a progress bar for builds.][cargo/5995]
2736
2737 Misc
2738 ----
2739 - [`rustdoc` allows you to specify what edition to treat your code as with the
2740   `--edition` option.][54057]
2741 - [`rustdoc` now has the `--color` (specify whether to output color) and
2742   `--error-format` (specify error format, e.g. `json`) options.][53003]
2743 - [We now distribute a `rust-gdbgui` script that invokes `gdbgui` with Rust
2744   debug symbols.][53774]
2745 - [Attributes from Rust tools such as `rustfmt` or `clippy` are now
2746   available,][53459] e.g. `#[rustfmt::skip]` will skip formatting the next item.
2747
2748 [50911]: https://github.com/rust-lang/rust/pull/50911/
2749 [51363]: https://github.com/rust-lang/rust/pull/51363/
2750 [51366]: https://github.com/rust-lang/rust/pull/51366/
2751 [52081]: https://github.com/rust-lang/rust/pull/52081/
2752 [53003]: https://github.com/rust-lang/rust/pull/53003/
2753 [53033]: https://github.com/rust-lang/rust/pull/53033/
2754 [53044]: https://github.com/rust-lang/rust/pull/53044/
2755 [53165]: https://github.com/rust-lang/rust/pull/53165/
2756 [53611]: https://github.com/rust-lang/rust/pull/53611/
2757 [53213]: https://github.com/rust-lang/rust/pull/53213/
2758 [53236]: https://github.com/rust-lang/rust/pull/53236/
2759 [53272]: https://github.com/rust-lang/rust/pull/53272/
2760 [53370]: https://github.com/rust-lang/rust/pull/53370/
2761 [53459]: https://github.com/rust-lang/rust/pull/53459/
2762 [53774]: https://github.com/rust-lang/rust/pull/53774/
2763 [53822]: https://github.com/rust-lang/rust/pull/53822/
2764 [54057]: https://github.com/rust-lang/rust/pull/54057/
2765 [54146]: https://github.com/rust-lang/rust/pull/54146/
2766 [54404]: https://github.com/rust-lang/rust/pull/54404/
2767 [cargo/5877]: https://github.com/rust-lang/cargo/pull/5877/
2768 [cargo/5878]: https://github.com/rust-lang/cargo/pull/5878/
2769 [cargo/5995]: https://github.com/rust-lang/cargo/pull/5995/
2770 [proc-macros]: https://doc.rust-lang.org/nightly/book/2018-edition/ch19-06-macros.html
2771
2772 [`Ipv4Addr::BROADCAST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.BROADCAST
2773 [`Ipv4Addr::LOCALHOST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.LOCALHOST
2774 [`Ipv4Addr::UNSPECIFIED`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.UNSPECIFIED
2775 [`Ipv6Addr::LOCALHOST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv6Addr.html#associatedconstant.LOCALHOST
2776 [`Ipv6Addr::UNSPECIFIED`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv6Addr.html#associatedconstant.UNSPECIFIED
2777 [`Iterator::find_map`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.find_map
2778 [`str::trim_end_matches`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim_end_matches
2779 [`str::trim_end`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim_end
2780 [`str::trim_start_matches`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim_start_matches
2781 [`str::trim_start`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim_start
2782
2783
2784 Version 1.29.2 (2018-10-11)
2785 ===========================
2786
2787 - [Workaround for an aliasing-related LLVM bug, which caused miscompilation.][54639]
2788 - The `rls-preview` component on the windows-gnu targets has been restored.
2789
2790 [54639]: https://github.com/rust-lang/rust/pull/54639
2791
2792
2793 Version 1.29.1 (2018-09-25)
2794 ===========================
2795
2796 Security Notes
2797 --------------
2798
2799 - The standard library's `str::repeat` function contained an out of bounds write
2800   caused by an integer overflow. This has been fixed by deterministically
2801   panicking when an overflow happens.
2802
2803   Thank you to Scott McMurray for responsibly disclosing this vulnerability to
2804   us.
2805
2806
2807 Version 1.29.0 (2018-09-13)
2808 ==========================
2809
2810 Compiler
2811 --------
2812 - [Bumped minimum LLVM version to 5.0.][51899]
2813 - [Added `powerpc64le-unknown-linux-musl` target.][51619]
2814 - [Added `aarch64-unknown-hermit` and `x86_64-unknown-hermit` targets.][52861]
2815 - [Upgraded to LLVM 7.][51966]
2816
2817 Libraries
2818 ---------
2819 - [`Once::call_once` no longer requires `Once` to be `'static`.][52239]
2820 - [`BuildHasherDefault` now implements `PartialEq` and `Eq`.][52402]
2821 - [`Box<CStr>`, `Box<OsStr>`, and `Box<Path>` now implement `Clone`.][51912]
2822 - [Implemented `PartialEq<&str>` for `OsString` and `PartialEq<OsString>`
2823   for `&str`.][51178]
2824 - [`Cell<T>` now allows `T` to be unsized.][50494]
2825 - [`SocketAddr` is now stable on Redox.][52656]
2826
2827 Stabilized APIs
2828 ---------------
2829 - [`Arc::downcast`]
2830 - [`Iterator::flatten`]
2831 - [`Rc::downcast`]
2832
2833 Cargo
2834 -----
2835 - [Cargo can silently fix some bad lockfiles.][cargo/5831] You can use
2836   `--locked` to disable this behavior.
2837 - [`cargo-install` will now allow you to cross compile an install
2838   using `--target`.][cargo/5614]
2839 - [Added the `cargo-fix` subcommand to automatically move project code from
2840   2015 edition to 2018.][cargo/5723]
2841 - [`cargo doc` can now optionally document private types using the
2842   `--document-private-items` flag.][cargo/5543]
2843
2844 Misc
2845 ----
2846 - [`rustdoc` now has the `--cap-lints` option which demotes all lints above
2847   the specified level to that level.][52354] For example `--cap-lints warn`
2848   will demote `deny` and `forbid` lints to `warn`.
2849 - [`rustc` and `rustdoc` will now have the exit code of `1` if compilation
2850   fails and `101` if there is a panic.][52197]
2851 - [A preview of clippy has been made available through rustup.][51122]
2852   You can install the preview with `rustup component add clippy-preview`.
2853
2854 Compatibility Notes
2855 -------------------
2856 - [`str::{slice_unchecked, slice_unchecked_mut}` are now deprecated.][51807]
2857   Use `str::get_unchecked(begin..end)` instead.
2858 - [`std::env::home_dir` is now deprecated for its unintuitive behavior.][51656]
2859   Consider using the `home_dir` function from
2860   https://crates.io/crates/dirs instead.
2861 - [`rustc` will no longer silently ignore invalid data in target spec.][52330]
2862 - [`cfg` attributes and `--cfg` command line flags are now more
2863   strictly validated.][53893]
2864
2865 [53893]: https://github.com/rust-lang/rust/pull/53893/
2866 [52861]: https://github.com/rust-lang/rust/pull/52861/
2867 [51966]: https://github.com/rust-lang/rust/pull/51966/
2868 [52656]: https://github.com/rust-lang/rust/pull/52656/
2869 [52239]: https://github.com/rust-lang/rust/pull/52239/
2870 [52330]: https://github.com/rust-lang/rust/pull/52330/
2871 [52354]: https://github.com/rust-lang/rust/pull/52354/
2872 [52402]: https://github.com/rust-lang/rust/pull/52402/
2873 [52103]: https://github.com/rust-lang/rust/pull/52103/
2874 [52197]: https://github.com/rust-lang/rust/pull/52197/
2875 [51807]: https://github.com/rust-lang/rust/pull/51807/
2876 [51899]: https://github.com/rust-lang/rust/pull/51899/
2877 [51912]: https://github.com/rust-lang/rust/pull/51912/
2878 [51511]: https://github.com/rust-lang/rust/pull/51511/
2879 [51619]: https://github.com/rust-lang/rust/pull/51619/
2880 [51656]: https://github.com/rust-lang/rust/pull/51656/
2881 [51178]: https://github.com/rust-lang/rust/pull/51178/
2882 [51122]: https://github.com/rust-lang/rust/pull/51122
2883 [50494]: https://github.com/rust-lang/rust/pull/50494/
2884 [cargo/5543]: https://github.com/rust-lang/cargo/pull/5543
2885 [cargo/5614]: https://github.com/rust-lang/cargo/pull/5614/
2886 [cargo/5723]: https://github.com/rust-lang/cargo/pull/5723/
2887 [cargo/5831]: https://github.com/rust-lang/cargo/pull/5831/
2888 [`Arc::downcast`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.downcast
2889 [`Iterator::flatten`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.flatten
2890 [`Rc::downcast`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.downcast
2891
2892
2893 Version 1.28.0 (2018-08-02)
2894 ===========================
2895
2896 Language
2897 --------
2898 - [The `#[repr(transparent)]` attribute is now stable.][51562] This attribute
2899   allows a Rust newtype wrapper (`struct NewType<T>(T);`) to be represented as
2900   the inner type across Foreign Function Interface (FFI) boundaries.
2901 - [The keywords `pure`, `sizeof`, `alignof`, and `offsetof` have been unreserved
2902   and can now be used as identifiers.][51196]
2903 - [The `GlobalAlloc` trait and `#[global_allocator]` attribute are now
2904   stable.][51241] This will allow users to specify a global allocator for
2905   their program.
2906 - [Unit test functions marked with the `#[test]` attribute can now return
2907   `Result<(), E: Debug>` in addition to `()`.][51298]
2908 - [The `lifetime` specifier for `macro_rules!` is now stable.][50385] This
2909   allows macros to easily target lifetimes.
2910
2911 Compiler
2912 --------
2913 - [The `s` and `z` optimisation levels are now stable.][50265] These optimisations
2914   prioritise making smaller binary sizes. `z` is the same as `s` with the
2915   exception that it does not vectorise loops, which typically results in an even
2916   smaller binary.
2917 - [The short error format is now stable.][49546] Specified with
2918   `--error-format=short` this option will provide a more compressed output of
2919   rust error messages.
2920 - [Added a lint warning when you have duplicated `macro_export`s.][50143]
2921 - [Reduced the number of allocations in the macro parser.][50855] This can
2922   improve compile times of macro heavy crates on average by 5%.
2923
2924 Libraries
2925 ---------
2926 - [Implemented `Default` for `&mut str`.][51306]
2927 - [Implemented `From<bool>` for all integer and unsigned number types.][50554]
2928 - [Implemented `Extend` for `()`.][50234]
2929 - [The `Debug` implementation of `time::Duration` should now be more easily
2930   human readable.][50364] Previously a `Duration` of one second would printed as
2931   `Duration { secs: 1, nanos: 0 }` and will now be printed as `1s`.
2932 - [Implemented `From<&String>` for `Cow<str>`, `From<&Vec<T>>` for `Cow<[T]>`,
2933   `From<Cow<CStr>>` for `CString`, `From<CString>, From<CStr>, From<&CString>`
2934   for `Cow<CStr>`, `From<OsString>, From<OsStr>, From<&OsString>` for
2935   `Cow<OsStr>`, `From<&PathBuf>` for `Cow<Path>`, and `From<Cow<Path>>`
2936   for `PathBuf`.][50170]
2937 - [Implemented `Shl` and `Shr` for `Wrapping<u128>`
2938   and `Wrapping<i128>`.][50465]
2939 - [`DirEntry::metadata` now uses `fstatat` instead of `lstat` when
2940   possible.][51050] This can provide up to a 40% speed increase.
2941 - [Improved error messages when using `format!`.][50610]
2942
2943 Stabilized APIs
2944 ---------------
2945 - [`Iterator::step_by`]
2946 - [`Path::ancestors`]
2947 - [`SystemTime::UNIX_EPOCH`]
2948 - [`alloc::GlobalAlloc`]
2949 - [`alloc::Layout`]
2950 - [`alloc::LayoutErr`]
2951 - [`alloc::System`]
2952 - [`alloc::alloc`]
2953 - [`alloc::alloc_zeroed`]
2954 - [`alloc::dealloc`]
2955 - [`alloc::realloc`]
2956 - [`alloc::handle_alloc_error`]
2957 - [`btree_map::Entry::or_default`]
2958 - [`fmt::Alignment`]
2959 - [`hash_map::Entry::or_default`]
2960 - [`iter::repeat_with`]
2961 - [`num::NonZeroUsize`]
2962 - [`num::NonZeroU128`]
2963 - [`num::NonZeroU16`]
2964 - [`num::NonZeroU32`]
2965 - [`num::NonZeroU64`]
2966 - [`num::NonZeroU8`]
2967 - [`ops::RangeBounds`]
2968 - [`slice::SliceIndex`]
2969 - [`slice::from_mut`]
2970 - [`slice::from_ref`]
2971 - [`{Any + Send + Sync}::downcast_mut`]
2972 - [`{Any + Send + Sync}::downcast_ref`]
2973 - [`{Any + Send + Sync}::is`]
2974
2975 Cargo
2976 -----
2977 - [Cargo will now no longer allow you to publish crates with build scripts that
2978   modify the `src` directory.][cargo/5584] The `src` directory in a crate should be
2979   considered to be immutable.
2980
2981 Misc
2982 ----
2983 - [The `suggestion_applicability` field in `rustc`'s json output is now
2984   stable.][50486] This will allow dev tools to check whether a code suggestion
2985   would apply to them.
2986
2987 Compatibility Notes
2988 -------------------
2989 - [Rust will consider trait objects with duplicated constraints to be the same
2990   type as without the duplicated constraint.][51276] For example the below code will
2991   now fail to compile.
2992   ```rust
2993   trait Trait {}
2994
2995   impl Trait + Send {
2996       fn test(&self) { println!("one"); } //~ ERROR duplicate definitions with name `test`
2997   }
2998
2999   impl Trait + Send + Send {
3000       fn test(&self) { println!("two"); }
3001   }
3002   ```
3003
3004 [49546]: https://github.com/rust-lang/rust/pull/49546/
3005 [50143]: https://github.com/rust-lang/rust/pull/50143/
3006 [50170]: https://github.com/rust-lang/rust/pull/50170/
3007 [50234]: https://github.com/rust-lang/rust/pull/50234/
3008 [50265]: https://github.com/rust-lang/rust/pull/50265/
3009 [50364]: https://github.com/rust-lang/rust/pull/50364/
3010 [50385]: https://github.com/rust-lang/rust/pull/50385/
3011 [50465]: https://github.com/rust-lang/rust/pull/50465/
3012 [50486]: https://github.com/rust-lang/rust/pull/50486/
3013 [50554]: https://github.com/rust-lang/rust/pull/50554/
3014 [50610]: https://github.com/rust-lang/rust/pull/50610/
3015 [50855]: https://github.com/rust-lang/rust/pull/50855/
3016 [51050]: https://github.com/rust-lang/rust/pull/51050/
3017 [51196]: https://github.com/rust-lang/rust/pull/51196/
3018 [51200]: https://github.com/rust-lang/rust/pull/51200/
3019 [51241]: https://github.com/rust-lang/rust/pull/51241/
3020 [51276]: https://github.com/rust-lang/rust/pull/51276/
3021 [51298]: https://github.com/rust-lang/rust/pull/51298/
3022 [51306]: https://github.com/rust-lang/rust/pull/51306/
3023 [51562]: https://github.com/rust-lang/rust/pull/51562/
3024 [cargo/5584]: https://github.com/rust-lang/cargo/pull/5584/
3025 [`Iterator::step_by`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.step_by
3026 [`Path::ancestors`]: https://doc.rust-lang.org/std/path/struct.Path.html#method.ancestors
3027 [`SystemTime::UNIX_EPOCH`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#associatedconstant.UNIX_EPOCH
3028 [`alloc::GlobalAlloc`]: https://doc.rust-lang.org/std/alloc/trait.GlobalAlloc.html
3029 [`alloc::Layout`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html
3030 [`alloc::LayoutErr`]: https://doc.rust-lang.org/std/alloc/struct.LayoutErr.html
3031 [`alloc::System`]: https://doc.rust-lang.org/std/alloc/struct.System.html
3032 [`alloc::alloc`]: https://doc.rust-lang.org/std/alloc/fn.alloc.html
3033 [`alloc::alloc_zeroed`]: https://doc.rust-lang.org/std/alloc/fn.alloc_zeroed.html
3034 [`alloc::dealloc`]: https://doc.rust-lang.org/std/alloc/fn.dealloc.html
3035 [`alloc::realloc`]: https://doc.rust-lang.org/std/alloc/fn.realloc.html
3036 [`alloc::handle_alloc_error`]: https://doc.rust-lang.org/std/alloc/fn.handle_alloc_error.html
3037 [`btree_map::Entry::or_default`]: https://doc.rust-lang.org/std/collections/btree_map/enum.Entry.html#method.or_default
3038 [`fmt::Alignment`]: https://doc.rust-lang.org/std/fmt/enum.Alignment.html
3039 [`hash_map::Entry::or_default`]: https://doc.rust-lang.org/std/collections/hash_map/enum.Entry.html#method.or_default
3040 [`iter::repeat_with`]: https://doc.rust-lang.org/std/iter/fn.repeat_with.html
3041 [`num::NonZeroUsize`]: https://doc.rust-lang.org/std/num/struct.NonZeroUsize.html
3042 [`num::NonZeroU128`]: https://doc.rust-lang.org/std/num/struct.NonZeroU128.html
3043 [`num::NonZeroU16`]: https://doc.rust-lang.org/std/num/struct.NonZeroU16.html
3044 [`num::NonZeroU32`]: https://doc.rust-lang.org/std/num/struct.NonZeroU32.html
3045 [`num::NonZeroU64`]: https://doc.rust-lang.org/std/num/struct.NonZeroU64.html
3046 [`num::NonZeroU8`]: https://doc.rust-lang.org/std/num/struct.NonZeroU8.html
3047 [`ops::RangeBounds`]: https://doc.rust-lang.org/std/ops/trait.RangeBounds.html
3048 [`slice::SliceIndex`]: https://doc.rust-lang.org/std/slice/trait.SliceIndex.html
3049 [`slice::from_mut`]: https://doc.rust-lang.org/std/slice/fn.from_mut.html
3050 [`slice::from_ref`]: https://doc.rust-lang.org/std/slice/fn.from_ref.html
3051 [`{Any + Send + Sync}::downcast_mut`]: https://doc.rust-lang.org/std/any/trait.Any.html#method.downcast_mut-2
3052 [`{Any + Send + Sync}::downcast_ref`]: https://doc.rust-lang.org/std/any/trait.Any.html#method.downcast_ref-2
3053 [`{Any + Send + Sync}::is`]: https://doc.rust-lang.org/std/any/trait.Any.html#method.is-2
3054
3055 Version 1.27.2 (2018-07-20)
3056 ===========================
3057
3058 Compatibility Notes
3059 -------------------
3060
3061 - The borrow checker was fixed to avoid potential unsoundness when using
3062   match ergonomics: [#52213][52213].
3063
3064 [52213]: https://github.com/rust-lang/rust/issues/52213
3065
3066 Version 1.27.1 (2018-07-10)
3067 ===========================
3068
3069 Security Notes
3070 --------------
3071
3072 - rustdoc would execute plugins in the /tmp/rustdoc/plugins directory
3073   when running, which enabled executing code as some other user on a
3074   given machine. This release fixes that vulnerability; you can read
3075   more about this on the [blog][rustdoc-sec]. The associated CVE is [CVE-2018-1000622].
3076
3077   Thank you to Red Hat for responsibly disclosing this vulnerability to us.
3078
3079 Compatibility Notes
3080 -------------------
3081
3082 - The borrow checker was fixed to avoid an additional potential unsoundness when using
3083   match ergonomics: [#51415][51415], [#49534][49534].
3084
3085 [51415]: https://github.com/rust-lang/rust/issues/51415
3086 [49534]: https://github.com/rust-lang/rust/issues/49534
3087 [rustdoc-sec]: https://blog.rust-lang.org/2018/07/06/security-advisory-for-rustdoc.html
3088 [CVE-2018-1000622]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=%20CVE-2018-1000622
3089
3090 Version 1.27.0 (2018-06-21)
3091 ==========================
3092
3093 Language
3094 --------
3095 - [Removed 'proc' from the reserved keywords list.][49699] This allows `proc` to
3096   be used as an identifier.
3097 - [The dyn syntax is now available.][49968] This syntax is equivalent to the
3098   bare `Trait` syntax, and should make it clearer when being used in tandem with
3099   `impl Trait` because it is equivalent to the following syntax:
3100   `&Trait == &dyn Trait`, `&mut Trait == &mut dyn Trait`, and
3101   `Box<Trait> == Box<dyn Trait>`.
3102 - [Attributes on generic parameters such as types and lifetimes are
3103   now stable.][48851] e.g.
3104   `fn foo<#[lifetime_attr] 'a, #[type_attr] T: 'a>() {}`
3105 - [The `#[must_use]` attribute can now also be used on functions as well as
3106   types.][48925] It provides a lint that by default warns users when the
3107   value returned by a function has not been used.
3108
3109 Compiler
3110 --------
3111 - [Added the `armv5te-unknown-linux-musleabi` target.][50423]
3112
3113 Libraries
3114 ---------
3115 - [SIMD (Single Instruction Multiple Data) on x86/x86_64 is now stable.][49664]
3116   This includes [`arch::x86`] & [`arch::x86_64`] modules which contain
3117   SIMD intrinsics, a new macro called `is_x86_feature_detected!`, the
3118   `#[target_feature(enable="")]` attribute, and adding `target_feature = ""` to
3119   the `cfg` attribute.
3120 - [A lot of methods for `[u8]`, `f32`, and `f64` previously only available in
3121   std are now available in core.][49896]
3122 - [The generic `Rhs` type parameter on `ops::{Shl, ShlAssign, Shr}` now defaults
3123   to `Self`.][49630]
3124 - [`std::str::replace` now has the `#[must_use]` attribute][50177] to clarify
3125   that the operation isn't done in place.
3126 - [`Clone::clone`, `Iterator::collect`, and `ToOwned::to_owned` now have
3127   the `#[must_use]` attribute][49533] to warn about unused potentially
3128   expensive allocations.
3129
3130 Stabilized APIs
3131 ---------------
3132 - [`DoubleEndedIterator::rfind`]
3133 - [`DoubleEndedIterator::rfold`]
3134 - [`DoubleEndedIterator::try_rfold`]
3135 - [`Duration::from_micros`]
3136 - [`Duration::from_nanos`]
3137 - [`Duration::subsec_micros`]
3138 - [`Duration::subsec_millis`]
3139 - [`HashMap::remove_entry`]
3140 - [`Iterator::try_fold`]
3141 - [`Iterator::try_for_each`]
3142 - [`NonNull::cast`]
3143 - [`Option::filter`]
3144 - [`String::replace_range`]
3145 - [`Take::set_limit`]
3146 - [`hint::unreachable_unchecked`]
3147 - [`os::unix::process::parent_id`]
3148 - [`ptr::swap_nonoverlapping`]
3149 - [`slice::rsplit_mut`]
3150 - [`slice::rsplit`]
3151 - [`slice::swap_with_slice`]
3152
3153 Cargo
3154 -----
3155 - [`cargo-metadata` now includes `authors`, `categories`, `keywords`,
3156   `readme`, and `repository` fields.][cargo/5386]
3157 - [`cargo-metadata` now includes a package's `metadata` table.][cargo/5360]
3158 - [Added the `--target-dir` optional argument.][cargo/5393] This allows you to specify
3159   a different directory than `target` for placing compilation artifacts.
3160 - [Cargo will be adding automatic target inference for binaries, benchmarks,
3161   examples, and tests in the Rust 2018 edition.][cargo/5335] If your project specifies
3162   specific targets, e.g. using `[[bin]]`, and have other binaries in locations
3163   where cargo would infer a binary, Cargo will produce a warning. You can
3164   disable this feature ahead of time by setting any of the following to false:
3165   `autobins`, `autobenches`, `autoexamples`, `autotests`.
3166 - [Cargo will now cache compiler information.][cargo/5359] This can be disabled by
3167   setting `CARGO_CACHE_RUSTC_INFO=0` in your environment.
3168
3169 Misc
3170 ----
3171 - [Added “The Rustc book” into the official documentation.][49707]
3172   [“The Rustc book”] documents and teaches how to use the rustc compiler.
3173 - [All books available on `doc.rust-lang.org` are now searchable.][49623]
3174
3175 Compatibility Notes
3176 -------------------
3177 - [Calling a `CharExt` or `StrExt` method directly on core will no longer
3178   work.][49896] e.g. `::core::prelude::v1::StrExt::is_empty("")` will not
3179   compile, `"".is_empty()` will still compile.
3180 - [`Debug` output on `atomic::{AtomicBool, AtomicIsize, AtomicPtr, AtomicUsize}`
3181   will only print the inner type.][48553] E.g.
3182   `print!("{:?}", AtomicBool::new(true))` will print `true`,
3183   not `AtomicBool(true)`.
3184 - [The maximum number for `repr(align(N))` is now 2²⁹.][50378] Previously you
3185   could enter higher numbers but they were not supported by LLVM. Up to 512MB
3186   alignment should cover all use cases.
3187 - The `.description()` method on the `std::error::Error` trait
3188   [has been soft-deprecated][50163]. It is no longer required to implement it.
3189
3190 [48553]: https://github.com/rust-lang/rust/pull/48553/
3191 [48851]: https://github.com/rust-lang/rust/pull/48851/
3192 [48925]: https://github.com/rust-lang/rust/pull/48925/
3193 [49533]: https://github.com/rust-lang/rust/pull/49533/
3194 [49623]: https://github.com/rust-lang/rust/pull/49623/
3195 [49630]: https://github.com/rust-lang/rust/pull/49630/
3196 [49664]: https://github.com/rust-lang/rust/pull/49664/
3197 [49699]: https://github.com/rust-lang/rust/pull/49699/
3198 [49707]: https://github.com/rust-lang/rust/pull/49707/
3199 [49719]: https://github.com/rust-lang/rust/pull/49719/
3200 [49896]: https://github.com/rust-lang/rust/pull/49896/
3201 [49968]: https://github.com/rust-lang/rust/pull/49968/
3202 [50163]: https://github.com/rust-lang/rust/pull/50163
3203 [50177]: https://github.com/rust-lang/rust/pull/50177/
3204 [50378]: https://github.com/rust-lang/rust/pull/50378/
3205 [50398]: https://github.com/rust-lang/rust/pull/50398/
3206 [50423]: https://github.com/rust-lang/rust/pull/50423/
3207 [cargo/5203]: https://github.com/rust-lang/cargo/pull/5203/
3208 [cargo/5335]: https://github.com/rust-lang/cargo/pull/5335/
3209 [cargo/5359]: https://github.com/rust-lang/cargo/pull/5359/
3210 [cargo/5360]: https://github.com/rust-lang/cargo/pull/5360/
3211 [cargo/5386]: https://github.com/rust-lang/cargo/pull/5386/
3212 [cargo/5393]: https://github.com/rust-lang/cargo/pull/5393/
3213 [`DoubleEndedIterator::rfind`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.rfind
3214 [`DoubleEndedIterator::rfold`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.rfold
3215 [`DoubleEndedIterator::try_rfold`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.try_rfold
3216 [`Duration::from_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_micros
3217 [`Duration::from_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_nanos
3218 [`Duration::subsec_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_micros
3219 [`Duration::subsec_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_millis
3220 [`HashMap::remove_entry`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.remove_entry
3221 [`Iterator::try_fold`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.try_fold
3222 [`Iterator::try_for_each`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.try_for_each
3223 [`NonNull::cast`]: https://doc.rust-lang.org/std/ptr/struct.NonNull.html#method.cast
3224 [`Option::filter`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.filter
3225 [`String::replace_range`]: https://doc.rust-lang.org/std/string/struct.String.html#method.replace_range
3226 [`Take::set_limit`]: https://doc.rust-lang.org/std/io/struct.Take.html#method.set_limit
3227 [`hint::unreachable_unchecked`]: https://doc.rust-lang.org/std/hint/fn.unreachable_unchecked.html
3228 [`os::unix::process::parent_id`]: https://doc.rust-lang.org/std/os/unix/process/fn.parent_id.html
3229 [`process::id`]: https://doc.rust-lang.org/std/process/fn.id.html
3230 [`ptr::swap_nonoverlapping`]: https://doc.rust-lang.org/std/ptr/fn.swap_nonoverlapping.html
3231 [`slice::rsplit_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rsplit_mut
3232 [`slice::rsplit`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rsplit
3233 [`slice::swap_with_slice`]: https://doc.rust-lang.org/std/primitive.slice.html#method.swap_with_slice
3234 [`arch::x86_64`]: https://doc.rust-lang.org/std/arch/x86_64/index.html
3235 [`arch::x86`]: https://doc.rust-lang.org/std/arch/x86/index.html
3236 [“The Rustc book”]: https://doc.rust-lang.org/rustc
3237
3238
3239 Version 1.26.2 (2018-06-05)
3240 ==========================
3241
3242 Compatibility Notes
3243 -------------------
3244
3245 - [The borrow checker was fixed to avoid unsoundness when using match ergonomics.][51117]
3246
3247 [51117]: https://github.com/rust-lang/rust/issues/51117
3248
3249
3250 Version 1.26.1 (2018-05-29)
3251 ==========================
3252
3253 Tools
3254 -----
3255
3256 - [RLS now works on Windows.][50646]
3257 - [Rustfmt stopped badly formatting text in some cases.][rustfmt/2695]
3258
3259
3260 Compatibility Notes
3261 --------
3262
3263 - [`fn main() -> impl Trait` no longer works for non-Termination
3264   trait.][50656]
3265   This reverts an accidental stabilization.
3266 - [`NaN > NaN` no longer returns true in const-fn contexts.][50812]
3267 - [Prohibit using turbofish for `impl Trait` in method arguments.][50950]
3268
3269 [50646]: https://github.com/rust-lang/rust/issues/50646
3270 [50656]: https://github.com/rust-lang/rust/pull/50656
3271 [50812]: https://github.com/rust-lang/rust/pull/50812
3272 [50950]: https://github.com/rust-lang/rust/issues/50950
3273 [rustfmt/2695]: https://github.com/rust-lang-nursery/rustfmt/issues/2695
3274
3275 Version 1.26.0 (2018-05-10)
3276 ==========================
3277
3278 Language
3279 --------
3280 - [Closures now implement `Copy` and/or `Clone` if all captured variables
3281   implement either or both traits.][49299]
3282 - [The inclusive range syntax e.g. `for x in 0..=10` is now stable.][47813]
3283 - [The `'_` lifetime is now stable. The underscore lifetime can be used anywhere a
3284   lifetime can be elided.][49458]
3285 - [`impl Trait` is now stable allowing you to have abstract types in returns
3286    or in function parameters.][49255] E.g. `fn foo() -> impl Iterator<Item=u8>` or
3287   `fn open(path: impl AsRef<Path>)`.
3288 - [Pattern matching will now automatically apply dereferences.][49394]
3289 - [128-bit integers in the form of `u128` and `i128` are now stable.][49101]
3290 - [`main` can now return `Result<(), E: Debug>`][49162] in addition to `()`.
3291 - [A lot of operations are now available in a const context.][46882] E.g. You
3292   can now index into constant arrays, reference and dereference into constants,
3293   and use tuple struct constructors.
3294 - [Fixed entry slice patterns are now stable.][48516] E.g.
3295   ```rust
3296   let points = [1, 2, 3, 4];
3297   match points {
3298       [1, 2, 3, 4] => println!("All points were sequential."),
3299       _ => println!("Not all points were sequential."),
3300   }
3301   ```
3302
3303
3304 Compiler
3305 --------
3306 - [LLD is now used as the default linker for `wasm32-unknown-unknown`.][48125]
3307 - [Fixed exponential projection complexity on nested types.][48296]
3308   This can provide up to a ~12% reduction in compile times for certain crates.
3309 - [Added the `--remap-path-prefix` option to rustc.][48359] Allowing you
3310   to remap path prefixes outputted by the compiler.
3311 - [Added `powerpc-unknown-netbsd` target.][48281]
3312
3313 Libraries
3314 ---------
3315 - [Implemented `From<u16> for usize` & `From<{u8, i16}> for isize`.][49305]
3316 - [Added hexadecimal formatting for integers with fmt::Debug][48978]
3317   e.g. `assert!(format!("{:02x?}", b"Foo\0") == "[46, 6f, 6f, 00]")`
3318 - [Implemented `Default, Hash` for `cmp::Reverse`.][48628]
3319 - [Optimized `str::repeat` being 8x faster in large cases.][48657]
3320 - [`ascii::escape_default` is now available in libcore.][48735]
3321 - [Trailing commas are now supported in std and core macros.][48056]
3322 - [Implemented `Copy, Clone` for `cmp::Reverse`][47379]
3323 - [Implemented `Clone` for `char::{ToLowercase, ToUppercase}`.][48629]
3324
3325 Stabilized APIs
3326 ---------------
3327 - [`*const T::add`]
3328 - [`*const T::copy_to_nonoverlapping`]
3329 - [`*const T::copy_to`]
3330 - [`*const T::read_unaligned`]
3331 - [`*const T::read_volatile`]
3332 - [`*const T::read`]
3333 - [`*const T::sub`]
3334 - [`*const T::wrapping_add`]
3335 - [`*const T::wrapping_sub`]
3336 - [`*mut T::add`]
3337 - [`*mut T::copy_to_nonoverlapping`]
3338 - [`*mut T::copy_to`]
3339 - [`*mut T::read_unaligned`]
3340 - [`*mut T::read_volatile`]
3341 - [`*mut T::read`]
3342 - [`*mut T::replace`]
3343 - [`*mut T::sub`]
3344 - [`*mut T::swap`]
3345 - [`*mut T::wrapping_add`]
3346 - [`*mut T::wrapping_sub`]
3347 - [`*mut T::write_bytes`]
3348 - [`*mut T::write_unaligned`]
3349 - [`*mut T::write_volatile`]
3350 - [`*mut T::write`]
3351 - [`Box::leak`]
3352 - [`FromUtf8Error::as_bytes`]
3353 - [`LocalKey::try_with`]
3354 - [`Option::cloned`]
3355 - [`btree_map::Entry::and_modify`]
3356 - [`fs::read_to_string`]
3357 - [`fs::read`]
3358 - [`fs::write`]
3359 - [`hash_map::Entry::and_modify`]
3360 - [`iter::FusedIterator`]
3361 - [`ops::RangeInclusive`]
3362 - [`ops::RangeToInclusive`]
3363 - [`process::id`]
3364 - [`slice::rotate_left`]
3365 - [`slice::rotate_right`]
3366 - [`String::retain`]
3367
3368
3369 Cargo
3370 -----
3371 - [Cargo will now output path to custom commands when `-v` is
3372   passed with `--list`][cargo/5041]
3373 - [The Cargo binary version is now the same as the Rust version][cargo/5083]
3374
3375 Misc
3376 ----
3377 - [The second edition of "The Rust Programming Language" book is now recommended
3378   over the first.][48404]
3379
3380 Compatibility Notes
3381 -------------------
3382
3383 - [aliasing a `Fn` trait as `dyn` no longer works.][48481] E.g. the following
3384   syntax is now invalid.
3385   ```
3386   use std::ops::Fn as dyn;
3387   fn g(_: Box<dyn(std::fmt::Debug)>) {}
3388   ```
3389 - [The result of dereferences are no longer promoted to `'static`.][47408]
3390   e.g.
3391   ```rust
3392   fn main() {
3393       const PAIR: &(i32, i32) = &(0, 1);
3394       let _reversed_pair: &'static _ = &(PAIR.1, PAIR.0); // Doesn't work
3395   }
3396   ```
3397 - [Deprecate `AsciiExt` trait in favor of inherent methods.][49109]
3398 - [`".e0"` will now no longer parse as `0.0` and will instead cause
3399   an error.][48235]
3400 - [Removed hoedown from rustdoc.][48274]
3401 - [Bounds on higher-kinded lifetimes a hard error.][48326]
3402
3403 [46882]: https://github.com/rust-lang/rust/pull/46882
3404 [47379]: https://github.com/rust-lang/rust/pull/47379
3405 [47408]: https://github.com/rust-lang/rust/pull/47408
3406 [47813]: https://github.com/rust-lang/rust/pull/47813
3407 [48056]: https://github.com/rust-lang/rust/pull/48056
3408 [48125]: https://github.com/rust-lang/rust/pull/48125
3409 [48166]: https://github.com/rust-lang/rust/pull/48166
3410 [48235]: https://github.com/rust-lang/rust/pull/48235
3411 [48274]: https://github.com/rust-lang/rust/pull/48274
3412 [48281]: https://github.com/rust-lang/rust/pull/48281
3413 [48296]: https://github.com/rust-lang/rust/pull/48296
3414 [48326]: https://github.com/rust-lang/rust/pull/48326
3415 [48359]: https://github.com/rust-lang/rust/pull/48359
3416 [48404]: https://github.com/rust-lang/rust/pull/48404
3417 [48481]: https://github.com/rust-lang/rust/pull/48481
3418 [48516]: https://github.com/rust-lang/rust/pull/48516
3419 [48628]: https://github.com/rust-lang/rust/pull/48628
3420 [48629]: https://github.com/rust-lang/rust/pull/48629
3421 [48657]: https://github.com/rust-lang/rust/pull/48657
3422 [48735]: https://github.com/rust-lang/rust/pull/48735
3423 [48978]: https://github.com/rust-lang/rust/pull/48978
3424 [49101]: https://github.com/rust-lang/rust/pull/49101
3425 [49109]: https://github.com/rust-lang/rust/pull/49109
3426 [49121]: https://github.com/rust-lang/rust/pull/49121
3427 [49162]: https://github.com/rust-lang/rust/pull/49162
3428 [49184]: https://github.com/rust-lang/rust/pull/49184
3429 [49234]: https://github.com/rust-lang/rust/pull/49234
3430 [49255]: https://github.com/rust-lang/rust/pull/49255
3431 [49299]: https://github.com/rust-lang/rust/pull/49299
3432 [49305]: https://github.com/rust-lang/rust/pull/49305
3433 [49394]: https://github.com/rust-lang/rust/pull/49394
3434 [49458]: https://github.com/rust-lang/rust/pull/49458
3435 [`*const T::add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add
3436 [`*const T::copy_to_nonoverlapping`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to_nonoverlapping
3437 [`*const T::copy_to`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to
3438 [`*const T::read_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_unaligned
3439 [`*const T::read_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_volatile
3440 [`*const T::read`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read
3441 [`*const T::sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.sub
3442 [`*const T::wrapping_add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_add
3443 [`*const T::wrapping_sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_sub
3444 [`*mut T::add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add-1
3445 [`*mut T::copy_to_nonoverlapping`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to_nonoverlapping-1
3446 [`*mut T::copy_to`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to-1
3447 [`*mut T::read_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_unaligned-1
3448 [`*mut T::read_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_volatile-1
3449 [`*mut T::read`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read-1
3450 [`*mut T::replace`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.replace
3451 [`*mut T::sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.sub-1
3452 [`*mut T::swap`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.swap
3453 [`*mut T::wrapping_add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_add-1
3454 [`*mut T::wrapping_sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_sub-1
3455 [`*mut T::write_bytes`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_bytes
3456 [`*mut T::write_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_unaligned
3457 [`*mut T::write_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_volatile
3458 [`*mut T::write`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write
3459 [`Box::leak`]: https://doc.rust-lang.org/std/boxed/struct.Box.html#method.leak
3460 [`FromUtf8Error::as_bytes`]: https://doc.rust-lang.org/std/string/struct.FromUtf8Error.html#method.as_bytes
3461 [`LocalKey::try_with`]: https://doc.rust-lang.org/std/thread/struct.LocalKey.html#method.try_with
3462 [`Option::cloned`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.cloned
3463 [`btree_map::Entry::and_modify`]: https://doc.rust-lang.org/std/collections/btree_map/enum.Entry.html#method.and_modify
3464 [`fs::read_to_string`]: https://doc.rust-lang.org/std/fs/fn.read_to_string.html
3465 [`fs::read`]: https://doc.rust-lang.org/std/fs/fn.read.html
3466 [`fs::write`]: https://doc.rust-lang.org/std/fs/fn.write.html
3467 [`hash_map::Entry::and_modify`]: https://doc.rust-lang.org/std/collections/hash_map/enum.Entry.html#method.and_modify
3468 [`iter::FusedIterator`]: https://doc.rust-lang.org/std/iter/trait.FusedIterator.html
3469 [`ops::RangeInclusive`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html
3470 [`ops::RangeToInclusive`]: https://doc.rust-lang.org/std/ops/struct.RangeToInclusive.html
3471 [`process::id`]: https://doc.rust-lang.org/std/process/fn.id.html
3472 [`slice::rotate_left`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rotate_left
3473 [`slice::rotate_right`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rotate_right
3474 [`String::retain`]: https://doc.rust-lang.org/std/string/struct.String.html#method.retain
3475 [cargo/5041]: https://github.com/rust-lang/cargo/pull/5041
3476 [cargo/5083]: https://github.com/rust-lang/cargo/pull/5083
3477
3478
3479 Version 1.25.0 (2018-03-29)
3480 ==========================
3481
3482 Language
3483 --------
3484 - [The `#[repr(align(x))]` attribute is now stable.][47006] [RFC 1358]
3485 - [You can now use nested groups of imports.][47948]
3486   e.g. `use std::{fs::File, io::Read, path::{Path, PathBuf}};`
3487 - [You can now have `|` at the start of a match arm.][47947] e.g.
3488 ```rust
3489 enum Foo { A, B, C }
3490
3491 fn main() {
3492     let x = Foo::A;
3493     match x {
3494         | Foo::A
3495         | Foo::B => println!("AB"),
3496         | Foo::C => println!("C"),
3497     }
3498 }
3499 ```
3500
3501 Compiler
3502 --------
3503 - [Upgraded to LLVM 6.][47828]
3504 - [Added `-C lto=val` option.][47521]
3505 - [Added `i586-unknown-linux-musl` target][47282]
3506
3507 Libraries
3508 ---------
3509 - [Impl Send for `process::Command` on Unix.][47760]
3510 - [Impl PartialEq and Eq for `ParseCharError`.][47790]
3511 - [`UnsafeCell::into_inner` is now safe.][47204]
3512 - [Implement libstd for CloudABI.][47268]
3513 - [`Float::{from_bits, to_bits}` is now available in libcore.][46931]
3514 - [Implement `AsRef<Path>` for Component][46985]
3515 - [Implemented `Write` for `Cursor<&mut Vec<u8>>`][46830]
3516 - [Moved `Duration` to libcore.][46666]
3517
3518 Stabilized APIs
3519 ---------------
3520 - [`Location::column`]
3521 - [`ptr::NonNull`]
3522
3523 The following functions can now be used in a constant expression.
3524 eg. `static MINUTE: Duration = Duration::from_secs(60);`
3525 - [`Duration::new`][47300]
3526 - [`Duration::from_secs`][47300]
3527 - [`Duration::from_millis`][47300]
3528
3529 Cargo
3530 -----
3531 - [`cargo new` no longer removes `rust` or `rs` prefixs/suffixs.][cargo/5013]
3532 - [`cargo new` now defaults to creating a binary crate, instead of a
3533   library crate.][cargo/5029]
3534
3535 Misc
3536 ----
3537 - [Rust by example is now shipped with new releases][46196]
3538
3539 Compatibility Notes
3540 -------------------
3541 - [Deprecated `net::lookup_host`.][47510]
3542 - [`rustdoc` has switched to pulldown as the default markdown renderer.][47398]
3543 - The borrow checker was sometimes incorrectly permitting overlapping borrows
3544   around indexing operations (see [#47349][47349]). This has been fixed (which also
3545   enabled some correct code that used to cause errors (e.g. [#33903][33903] and [#46095][46095]).
3546 - [Removed deprecated unstable attribute `#[simd]`.][47251]
3547
3548 [33903]: https://github.com/rust-lang/rust/pull/33903
3549 [47947]: https://github.com/rust-lang/rust/pull/47947
3550 [47948]: https://github.com/rust-lang/rust/pull/47948
3551 [47760]: https://github.com/rust-lang/rust/pull/47760
3552 [47790]: https://github.com/rust-lang/rust/pull/47790
3553 [47828]: https://github.com/rust-lang/rust/pull/47828
3554 [47398]: https://github.com/rust-lang/rust/pull/47398
3555 [47510]: https://github.com/rust-lang/rust/pull/47510
3556 [47521]: https://github.com/rust-lang/rust/pull/47521
3557 [47204]: https://github.com/rust-lang/rust/pull/47204
3558 [47251]: https://github.com/rust-lang/rust/pull/47251
3559 [47268]: https://github.com/rust-lang/rust/pull/47268
3560 [47282]: https://github.com/rust-lang/rust/pull/47282
3561 [47300]: https://github.com/rust-lang/rust/pull/47300
3562 [47349]: https://github.com/rust-lang/rust/pull/47349
3563 [46931]: https://github.com/rust-lang/rust/pull/46931
3564 [46985]: https://github.com/rust-lang/rust/pull/46985
3565 [47006]: https://github.com/rust-lang/rust/pull/47006
3566 [46830]: https://github.com/rust-lang/rust/pull/46830
3567 [46095]: https://github.com/rust-lang/rust/pull/46095
3568 [46666]: https://github.com/rust-lang/rust/pull/46666
3569 [46196]: https://github.com/rust-lang/rust/pull/46196
3570 [cargo/5013]: https://github.com/rust-lang/cargo/pull/5013
3571 [cargo/5029]: https://github.com/rust-lang/cargo/pull/5029
3572 [RFC 1358]: https://github.com/rust-lang/rfcs/pull/1358
3573 [`Location::column`]: https://doc.rust-lang.org/std/panic/struct.Location.html#method.column
3574 [`ptr::NonNull`]: https://doc.rust-lang.org/std/ptr/struct.NonNull.html
3575
3576
3577 Version 1.24.1 (2018-03-01)
3578 ==========================
3579
3580  - [Do not abort when unwinding through FFI][48251]
3581  - [Emit UTF-16 files for linker arguments on Windows][48318]
3582  - [Make the error index generator work again][48308]
3583  - [Cargo will warn on Windows 7 if an update is needed][cargo/5069].
3584
3585 [48251]: https://github.com/rust-lang/rust/issues/48251
3586 [48308]: https://github.com/rust-lang/rust/issues/48308
3587 [48318]: https://github.com/rust-lang/rust/issues/48318
3588 [cargo/5069]: https://github.com/rust-lang/cargo/pull/5069
3589
3590
3591 Version 1.24.0 (2018-02-15)
3592 ==========================
3593
3594 Language
3595 --------
3596 - [External `sysv64` ffi is now available.][46528]
3597   eg. `extern "sysv64" fn foo () {}`
3598
3599 Compiler
3600 --------
3601 - [rustc now uses 16 codegen units by default for release builds.][46910]
3602   For the fastest builds, utilize `codegen-units=1`.
3603 - [Added `armv4t-unknown-linux-gnueabi` target.][47018]
3604 - [Add `aarch64-unknown-openbsd` support][46760]
3605
3606 Libraries
3607 ---------
3608 - [`str::find::<char>` now uses memchr.][46735] This should lead to a 10x
3609   improvement in performance in the majority of cases.
3610 - [`OsStr`'s `Debug` implementation is now lossless and consistent
3611   with Windows.][46798]
3612 - [`time::{SystemTime, Instant}` now implement `Hash`.][46828]
3613 - [impl `From<bool>` for `AtomicBool`][46293]
3614 - [impl `From<{CString, &CStr}>` for `{Arc<CStr>, Rc<CStr>}`][45990]
3615 - [impl `From<{OsString, &OsStr}>` for `{Arc<OsStr>, Rc<OsStr>}`][45990]
3616 - [impl `From<{PathBuf, &Path}>` for `{Arc<Path>, Rc<Path>}`][45990]
3617 - [float::from_bits now just uses transmute.][46012] This provides
3618   some optimisations from LLVM.
3619 - [Copied `AsciiExt` methods onto `char`][46077]
3620 - [Remove `T: Sized` requirement on `ptr::is_null()`][46094]
3621 - [impl `From<RecvError>` for `{TryRecvError, RecvTimeoutError}`][45506]
3622 - [Optimised `f32::{min, max}` to generate more efficient x86 assembly][47080]
3623 - [`[u8]::contains` now uses memchr which provides a 3x speed improvement][46713]
3624
3625 Stabilized APIs
3626 ---------------
3627 - [`RefCell::replace`]
3628 - [`RefCell::swap`]
3629 - [`atomic::spin_loop_hint`]
3630
3631 The following functions can now be used in a constant expression.
3632 eg. `let buffer: [u8; size_of::<usize>()];`, `static COUNTER: AtomicUsize = AtomicUsize::new(1);`
3633
3634 - [`AtomicBool::new`][46287]
3635 - [`AtomicUsize::new`][46287]
3636 - [`AtomicIsize::new`][46287]
3637 - [`AtomicPtr::new`][46287]
3638 - [`Cell::new`][46287]
3639 - [`{integer}::min_value`][46287]
3640 - [`{integer}::max_value`][46287]
3641 - [`mem::size_of`][46287]
3642 - [`mem::align_of`][46287]
3643 - [`ptr::null`][46287]
3644 - [`ptr::null_mut`][46287]
3645 - [`RefCell::new`][46287]
3646 - [`UnsafeCell::new`][46287]
3647
3648 Cargo
3649 -----
3650 - [Added a `workspace.default-members` config that
3651   overrides implied `--all` in virtual workspaces.][cargo/4743]
3652 - [Enable incremental by default on development builds.][cargo/4817] Also added
3653   configuration keys to `Cargo.toml` and `.cargo/config` to disable on a
3654   per-project or global basis respectively.
3655
3656 Misc
3657 ----
3658
3659 Compatibility Notes
3660 -------------------
3661 - [Floating point types `Debug` impl now always prints a decimal point.][46831]
3662 - [`Ipv6Addr` now rejects superfluous `::`'s in IPv6 addresses][46671] This is
3663   in accordance with IETF RFC 4291 §2.2.
3664 - [Unwinding will no longer go past FFI boundaries, and will instead abort.][46833]
3665 - [`Formatter::flags` method is now deprecated.][46284] The `sign_plus`,
3666   `sign_minus`, `alternate`, and `sign_aware_zero_pad` should be used instead.
3667 - [Leading zeros in tuple struct members is now an error][47084]
3668 - [`column!()` macro is one-based instead of zero-based][46977]
3669 - [`fmt::Arguments` can no longer be shared across threads][45198]
3670 - [Access to `#[repr(packed)]` struct fields is now unsafe][44884]
3671 - [Cargo sets a different working directory for the compiler][cargo/4788]
3672
3673 [44884]: https://github.com/rust-lang/rust/pull/44884
3674 [45198]: https://github.com/rust-lang/rust/pull/45198
3675 [45506]: https://github.com/rust-lang/rust/pull/45506
3676 [45904]: https://github.com/rust-lang/rust/pull/45904
3677 [45990]: https://github.com/rust-lang/rust/pull/45990
3678 [46012]: https://github.com/rust-lang/rust/pull/46012
3679 [46077]: https://github.com/rust-lang/rust/pull/46077
3680 [46094]: https://github.com/rust-lang/rust/pull/46094
3681 [46284]: https://github.com/rust-lang/rust/pull/46284
3682 [46287]: https://github.com/rust-lang/rust/pull/46287
3683 [46293]: https://github.com/rust-lang/rust/pull/46293
3684 [46528]: https://github.com/rust-lang/rust/pull/46528
3685 [46671]: https://github.com/rust-lang/rust/pull/46671
3686 [46713]: https://github.com/rust-lang/rust/pull/46713
3687 [46735]: https://github.com/rust-lang/rust/pull/46735
3688 [46749]: https://github.com/rust-lang/rust/pull/46749
3689 [46760]: https://github.com/rust-lang/rust/pull/46760
3690 [46798]: https://github.com/rust-lang/rust/pull/46798
3691 [46828]: https://github.com/rust-lang/rust/pull/46828
3692 [46831]: https://github.com/rust-lang/rust/pull/46831
3693 [46833]: https://github.com/rust-lang/rust/pull/46833
3694 [46910]: https://github.com/rust-lang/rust/pull/46910
3695 [46977]: https://github.com/rust-lang/rust/pull/46977
3696 [47018]: https://github.com/rust-lang/rust/pull/47018
3697 [47080]: https://github.com/rust-lang/rust/pull/47080
3698 [47084]: https://github.com/rust-lang/rust/pull/47084
3699 [cargo/4743]: https://github.com/rust-lang/cargo/pull/4743
3700 [cargo/4788]: https://github.com/rust-lang/cargo/pull/4788
3701 [cargo/4817]: https://github.com/rust-lang/cargo/pull/4817
3702 [`RefCell::replace`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.replace
3703 [`RefCell::swap`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.swap
3704 [`atomic::spin_loop_hint`]: https://doc.rust-lang.org/std/sync/atomic/fn.spin_loop_hint.html
3705
3706
3707 Version 1.23.0 (2018-01-04)
3708 ==========================
3709
3710 Language
3711 --------
3712 - [Arbitrary `auto` traits are now permitted in trait objects.][45772]
3713 - [rustc now uses subtyping on the left hand side of binary operations.][45435]
3714   Which should fix some confusing errors in some operations.
3715
3716 Compiler
3717 --------
3718 - [Enabled `TrapUnreachable` in LLVM which should mitigate the impact of
3719   undefined behavior.][45920]
3720 - [rustc now suggests renaming import if names clash.][45660]
3721 - [Display errors/warnings correctly when there are zero-width or
3722   wide characters.][45711]
3723 - [rustc now avoids unnecessary copies of arguments that are
3724   simple bindings][45380] This should improve memory usage on average by 5-10%.
3725 - [Updated musl used to build musl rustc to 1.1.17][45393]
3726
3727 Libraries
3728 ---------
3729 - [Allow a trailing comma in `assert_eq/ne` macro][45887]
3730 - [Implement Hash for raw pointers to unsized types][45483]
3731 - [impl `From<*mut T>` for `AtomicPtr<T>`][45610]
3732 - [impl `From<usize/isize>` for `AtomicUsize/AtomicIsize`.][45610]
3733 - [Removed the `T: Sync` requirement for `RwLock<T>: Send`][45267]
3734 - [Removed `T: Sized` requirement for `{<*const T>, <*mut T>}::as_ref`
3735   and `<*mut T>::as_mut`][44932]
3736 - [Optimized `Thread::{park, unpark}` implementation][45524]
3737 - [Improved `SliceExt::binary_search` performance.][45333]
3738 - [impl `FromIterator<()>` for `()`][45379]
3739 - [Copied `AsciiExt` trait methods to primitive types.][44042] Use of `AsciiExt`
3740   is now deprecated.
3741
3742 Stabilized APIs
3743 ---------------
3744
3745 Cargo
3746 -----
3747 - [Cargo now supports uninstallation of multiple packages][cargo/4561]
3748   eg. `cargo uninstall foo bar` uninstalls `foo` and `bar`.
3749 - [Added unit test checking to `cargo check`][cargo/4592]
3750 - [Cargo now lets you install a specific version
3751   using `cargo install --version`][cargo/4637]
3752
3753 Misc
3754 ----
3755 - [Releases now ship with the Cargo book documentation.][45692]
3756 - [rustdoc now prints rendering warnings on every run.][45324]
3757
3758 Compatibility Notes
3759 -------------------
3760 - [Changes have been made to type equality to make it more correct,
3761   in rare cases this could break some code.][45853] [Tracking issue for
3762   further information][45852]
3763 - [`char::escape_debug` now uses Unicode 10 over 9.][45571]
3764 - [Upgraded Android SDK to 27, and NDK to r15c.][45580] This drops support for
3765   Android 9, the minimum supported version is Android 14.
3766 - [Bumped the minimum LLVM to 3.9][45326]
3767
3768 [44042]: https://github.com/rust-lang/rust/pull/44042
3769 [44932]: https://github.com/rust-lang/rust/pull/44932
3770 [45267]: https://github.com/rust-lang/rust/pull/45267
3771 [45324]: https://github.com/rust-lang/rust/pull/45324
3772 [45326]: https://github.com/rust-lang/rust/pull/45326
3773 [45333]: https://github.com/rust-lang/rust/pull/45333
3774 [45379]: https://github.com/rust-lang/rust/pull/45379
3775 [45380]: https://github.com/rust-lang/rust/pull/45380
3776 [45393]: https://github.com/rust-lang/rust/pull/45393
3777 [45435]: https://github.com/rust-lang/rust/pull/45435
3778 [45483]: https://github.com/rust-lang/rust/pull/45483
3779 [45524]: https://github.com/rust-lang/rust/pull/45524
3780 [45571]: https://github.com/rust-lang/rust/pull/45571
3781 [45580]: https://github.com/rust-lang/rust/pull/45580
3782 [45610]: https://github.com/rust-lang/rust/pull/45610
3783 [45660]: https://github.com/rust-lang/rust/pull/45660
3784 [45692]: https://github.com/rust-lang/rust/pull/45692
3785 [45711]: https://github.com/rust-lang/rust/pull/45711
3786 [45772]: https://github.com/rust-lang/rust/pull/45772
3787 [45852]: https://github.com/rust-lang/rust/issues/45852
3788 [45853]: https://github.com/rust-lang/rust/pull/45853
3789 [45887]: https://github.com/rust-lang/rust/pull/45887
3790 [45920]: https://github.com/rust-lang/rust/pull/45920
3791 [cargo/4561]: https://github.com/rust-lang/cargo/pull/4561
3792 [cargo/4592]: https://github.com/rust-lang/cargo/pull/4592
3793 [cargo/4637]: https://github.com/rust-lang/cargo/pull/4637
3794
3795
3796 Version 1.22.1 (2017-11-22)
3797 ==========================
3798
3799 - [Update Cargo to fix an issue with macOS 10.13 "High Sierra"][46183]
3800
3801 [46183]: https://github.com/rust-lang/rust/pull/46183
3802
3803 Version 1.22.0 (2017-11-22)
3804 ==========================
3805
3806 Language
3807 --------
3808 - [`non_snake_case` lint now allows extern no-mangle functions][44966]
3809 - [Now accepts underscores in unicode escapes][43716]
3810 - [`T op= &T` now works for numeric types.][44287] eg. `let mut x = 2; x += &8;`
3811 - [types that impl `Drop` are now allowed in `const` and `static` types][44456]
3812
3813 Compiler
3814 --------
3815 - [rustc now defaults to having 16 codegen units at debug on supported platforms.][45064]
3816 - [rustc will no longer inline in codegen units when compiling for debug][45075]
3817   This should decrease compile times for debug builds.
3818 - [strict memory alignment now enabled on ARMv6][45094]
3819 - [Remove support for the PNaCl target `le32-unknown-nacl`][45041]
3820
3821 Libraries
3822 ---------
3823 - [Allow atomic operations up to 32 bits
3824   on `armv5te_unknown_linux_gnueabi`][44978]
3825 - [`Box<Error>` now impls `From<Cow<str>>`][44466]
3826 - [`std::mem::Discriminant` is now guaranteed to be `Send + Sync`][45095]
3827 - [`fs::copy` now returns the length of the main stream on NTFS.][44895]
3828 - [Properly detect overflow in `Instant += Duration`.][44220]
3829 - [impl `Hasher` for `{&mut Hasher, Box<Hasher>}`][44015]
3830 - [impl `fmt::Debug` for `SplitWhitespace`.][44303]
3831 - [`Option<T>` now impls `Try`][42526] This allows for using `?` with `Option` types.
3832
3833 Stabilized APIs
3834 ---------------
3835
3836 Cargo
3837 -----
3838 - [Cargo will now build multi file examples in subdirectories of the `examples`
3839   folder that have a `main.rs` file.][cargo/4496]
3840 - [Changed `[root]` to `[package]` in `Cargo.lock`][cargo/4571] Packages with
3841   the old format will continue to work and can be updated with `cargo update`.
3842 - [Now supports vendoring git repositories][cargo/3992]
3843
3844 Misc
3845 ----
3846 - [`libbacktrace` is now available on Apple platforms.][44251]
3847 - [Stabilised the `compile_fail` attribute for code fences in doc-comments.][43949]
3848   This now lets you specify that a given code example will fail to compile.
3849
3850 Compatibility Notes
3851 -------------------
3852 - [The minimum Android version that rustc can build for has been bumped
3853   to `4.0` from `2.3`][45656]
3854 - [Allowing `T op= &T` for numeric types has broken some type
3855   inference cases][45480]
3856
3857
3858 [42526]: https://github.com/rust-lang/rust/pull/42526
3859 [43017]: https://github.com/rust-lang/rust/pull/43017
3860 [43716]: https://github.com/rust-lang/rust/pull/43716
3861 [43949]: https://github.com/rust-lang/rust/pull/43949
3862 [44015]: https://github.com/rust-lang/rust/pull/44015
3863 [44220]: https://github.com/rust-lang/rust/pull/44220
3864 [44251]: https://github.com/rust-lang/rust/pull/44251
3865 [44287]: https://github.com/rust-lang/rust/pull/44287
3866 [44303]: https://github.com/rust-lang/rust/pull/44303
3867 [44456]: https://github.com/rust-lang/rust/pull/44456
3868 [44466]: https://github.com/rust-lang/rust/pull/44466
3869 [44895]: https://github.com/rust-lang/rust/pull/44895
3870 [44966]: https://github.com/rust-lang/rust/pull/44966
3871 [44978]: https://github.com/rust-lang/rust/pull/44978
3872 [45041]: https://github.com/rust-lang/rust/pull/45041
3873 [45064]: https://github.com/rust-lang/rust/pull/45064
3874 [45075]: https://github.com/rust-lang/rust/pull/45075
3875 [45094]: https://github.com/rust-lang/rust/pull/45094
3876 [45095]: https://github.com/rust-lang/rust/pull/45095
3877 [45480]: https://github.com/rust-lang/rust/issues/45480
3878 [45656]: https://github.com/rust-lang/rust/pull/45656
3879 [cargo/3992]: https://github.com/rust-lang/cargo/pull/3992
3880 [cargo/4496]: https://github.com/rust-lang/cargo/pull/4496
3881 [cargo/4571]: https://github.com/rust-lang/cargo/pull/4571
3882
3883
3884
3885
3886
3887
3888 Version 1.21.0 (2017-10-12)
3889 ==========================
3890
3891 Language
3892 --------
3893 - [You can now use static references for literals.][43838]
3894   Example:
3895   ```rust
3896   fn main() {
3897       let x: &'static u32 = &0;
3898   }
3899   ```
3900 - [Relaxed path syntax. Optional `::` before `<` is now allowed in all contexts.][43540]
3901   Example:
3902   ```rust
3903   my_macro!(Vec<i32>::new); // Always worked
3904   my_macro!(Vec::<i32>::new); // Now works
3905   ```
3906
3907 Compiler
3908 --------
3909 - [Upgraded jemalloc to 4.5.0][43911]
3910 - [Enabled unwinding panics on Redox][43917]
3911 - [Now runs LLVM in parallel during translation phase.][43506]
3912   This should reduce peak memory usage.
3913
3914 Libraries
3915 ---------
3916 - [Generate builtin impls for `Clone` for all arrays and tuples that
3917   are `T: Clone`][43690]
3918 - [`Stdin`, `Stdout`, and `Stderr` now implement `AsRawFd`.][43459]
3919 - [`Rc` and `Arc` now implement `From<&[T]> where T: Clone`, `From<str>`,
3920   `From<String>`, `From<Box<T>> where T: ?Sized`, and `From<Vec<T>>`.][42565]
3921
3922 Stabilized APIs
3923 ---------------
3924
3925 [`std::mem::discriminant`]
3926
3927 Cargo
3928 -----
3929 - [You can now call `cargo install` with multiple package names][cargo/4216]
3930 - [Cargo commands inside a virtual workspace will now implicitly
3931   pass `--all`][cargo/4335]
3932 - [Added a `[patch]` section to `Cargo.toml` to handle
3933   prepublication dependencies][cargo/4123] [RFC 1969]
3934 - [`include` & `exclude` fields in `Cargo.toml` now accept gitignore
3935   like patterns][cargo/4270]
3936 - [Added the `--all-targets` option][cargo/4400]
3937 - [Using required dependencies as a feature is now deprecated and emits
3938   a warning][cargo/4364]
3939
3940
3941 Misc
3942 ----
3943 - [Cargo docs are moving][43916]
3944   to [doc.rust-lang.org/cargo](https://doc.rust-lang.org/cargo)
3945 - [The rustdoc book is now available][43863]
3946   at [doc.rust-lang.org/rustdoc](https://doc.rust-lang.org/rustdoc)
3947 - [Added a preview of RLS has been made available through rustup][44204]
3948   Install with `rustup component add rls-preview`
3949 - [`std::os` documentation for Unix, Linux, and Windows now appears on doc.rust-lang.org][43348]
3950   Previously only showed `std::os::unix`.
3951
3952 Compatibility Notes
3953 -------------------
3954 - [Changes in method matching against higher-ranked types][43880] This may cause
3955   breakage in subtyping corner cases. [A more in-depth explanation is available.][info/43880]
3956 - [rustc's JSON error output's byte position start at top of file.][42973]
3957   Was previously relative to the rustc's internal `CodeMap` struct which
3958   required the unstable library `libsyntax` to correctly use.
3959 - [`unused_results` lint no longer ignores booleans][43728]
3960
3961 [42565]: https://github.com/rust-lang/rust/pull/42565
3962 [42973]: https://github.com/rust-lang/rust/pull/42973
3963 [43348]: https://github.com/rust-lang/rust/pull/43348
3964 [43459]: https://github.com/rust-lang/rust/pull/43459
3965 [43506]: https://github.com/rust-lang/rust/pull/43506
3966 [43540]: https://github.com/rust-lang/rust/pull/43540
3967 [43690]: https://github.com/rust-lang/rust/pull/43690
3968 [43728]: https://github.com/rust-lang/rust/pull/43728
3969 [43838]: https://github.com/rust-lang/rust/pull/43838
3970 [43863]: https://github.com/rust-lang/rust/pull/43863
3971 [43880]: https://github.com/rust-lang/rust/pull/43880
3972 [43911]: https://github.com/rust-lang/rust/pull/43911
3973 [43916]: https://github.com/rust-lang/rust/pull/43916
3974 [43917]: https://github.com/rust-lang/rust/pull/43917
3975 [44204]: https://github.com/rust-lang/rust/pull/44204
3976 [cargo/4123]: https://github.com/rust-lang/cargo/pull/4123
3977 [cargo/4216]: https://github.com/rust-lang/cargo/pull/4216
3978 [cargo/4270]: https://github.com/rust-lang/cargo/pull/4270
3979 [cargo/4335]: https://github.com/rust-lang/cargo/pull/4335
3980 [cargo/4364]: https://github.com/rust-lang/cargo/pull/4364
3981 [cargo/4400]: https://github.com/rust-lang/cargo/pull/4400
3982 [RFC 1969]: https://github.com/rust-lang/rfcs/pull/1969
3983 [info/43880]: https://github.com/rust-lang/rust/issues/44224#issuecomment-330058902
3984 [`std::mem::discriminant`]: https://doc.rust-lang.org/std/mem/fn.discriminant.html
3985
3986 Version 1.20.0 (2017-08-31)
3987 ===========================
3988
3989 Language
3990 --------
3991 - [Associated constants are now stabilised.][42809]
3992 - [A lot of macro bugs are now fixed.][42913]
3993
3994 Compiler
3995 --------
3996
3997 - [Struct fields are now properly coerced to the expected field type.][42807]
3998 - [Enabled wasm LLVM backend][42571] WASM can now be built with the
3999   `wasm32-experimental-emscripten` target.
4000 - [Changed some of the error messages to be more helpful.][42033]
4001 - [Add support for RELRO(RELocation Read-Only) for platforms that support
4002   it.][43170]
4003 - [rustc now reports the total number of errors on compilation failure][43015]
4004   previously this was only the number of errors in the pass that failed.
4005 - [Expansion in rustc has been sped up 29x.][42533]
4006 - [added `msp430-none-elf` target.][43099]
4007 - [rustc will now suggest one-argument enum variant to fix type mismatch when
4008   applicable][43178]
4009 - [Fixes backtraces on Redox][43228]
4010 - [rustc now identifies different versions of same crate when absolute paths of
4011   different types match in an error message.][42826]
4012
4013 Libraries
4014 ---------
4015
4016
4017 - [Relaxed Debug constraints on `{HashMap,BTreeMap}::{Keys,Values}`.][42854]
4018 - [Impl `PartialEq`, `Eq`, `PartialOrd`, `Ord`, `Debug`, `Hash` for unsized
4019   tuples.][43011]
4020 - [Impl `fmt::{Display, Debug}` for `Ref`, `RefMut`, `MutexGuard`,
4021   `RwLockReadGuard`, `RwLockWriteGuard`][42822]
4022 - [Impl `Clone` for `DefaultHasher`.][42799]
4023 - [Impl `Sync` for `SyncSender`.][42397]
4024 - [Impl `FromStr` for `char`][42271]
4025 - [Fixed how `{f32, f64}::{is_sign_negative, is_sign_positive}` handles
4026   NaN.][42431]
4027 - [allow messages in the `unimplemented!()` macro.][42155]
4028   ie. `unimplemented!("Waiting for 1.21 to be stable")`
4029 - [`pub(restricted)` is now supported in the `thread_local!` macro.][43185]
4030 - [Upgrade to Unicode 10.0.0][42999]
4031 - [Reimplemented `{f32, f64}::{min, max}` in Rust instead of using CMath.][42430]
4032 - [Skip the main thread's manual stack guard on Linux][43072]
4033 - [Iterator::nth for `ops::{Range, RangeFrom}` is now done in O(1) time][43077]
4034 - [`#[repr(align(N))]` attribute max number is now 2^31 - 1.][43097] This was
4035   previously 2^15.
4036 - [`{OsStr, Path}::Display` now avoids allocations where possible][42613]
4037
4038 Stabilized APIs
4039 ---------------
4040
4041 - [`CStr::into_c_string`]
4042 - [`CString::as_c_str`]
4043 - [`CString::into_boxed_c_str`]
4044 - [`Chain::get_mut`]
4045 - [`Chain::get_ref`]
4046 - [`Chain::into_inner`]
4047 - [`Option::get_or_insert_with`]
4048 - [`Option::get_or_insert`]
4049 - [`OsStr::into_os_string`]
4050 - [`OsString::into_boxed_os_str`]
4051 - [`Take::get_mut`]
4052 - [`Take::get_ref`]
4053 - [`Utf8Error::error_len`]
4054 - [`char::EscapeDebug`]
4055 - [`char::escape_debug`]
4056 - [`compile_error!`]
4057 - [`f32::from_bits`]
4058 - [`f32::to_bits`]
4059 - [`f64::from_bits`]
4060 - [`f64::to_bits`]
4061 - [`mem::ManuallyDrop`]
4062 - [`slice::sort_unstable_by_key`]
4063 - [`slice::sort_unstable_by`]
4064 - [`slice::sort_unstable`]
4065 - [`str::from_boxed_utf8_unchecked`]
4066 - [`str::as_bytes_mut`]
4067 - [`str::as_bytes_mut`]
4068 - [`str::from_utf8_mut`]
4069 - [`str::from_utf8_unchecked_mut`]
4070 - [`str::get_mut`]
4071 - [`str::get_unchecked_mut`]
4072 - [`str::get_unchecked`]
4073 - [`str::get`]
4074 - [`str::into_boxed_bytes`]
4075
4076
4077 Cargo
4078 -----
4079 - [Cargo API token location moved from `~/.cargo/config` to
4080   `~/.cargo/credentials`.][cargo/3978]
4081 - [Cargo will now build `main.rs` binaries that are in sub-directories of
4082   `src/bin`.][cargo/4214] ie. Having `src/bin/server/main.rs` and
4083   `src/bin/client/main.rs` generates `target/debug/server` and `target/debug/client`
4084 - [You can now specify version of a binary when installed through
4085   `cargo install` using `--vers`.][cargo/4229]
4086 - [Added `--no-fail-fast` flag to cargo to run all benchmarks regardless of
4087   failure.][cargo/4248]
4088 - [Changed the convention around which file is the crate root.][cargo/4259]
4089 - [The `include`/`exclude` property in `Cargo.toml` now accepts gitignore paths
4090   instead of glob patterns][cargo/4270]. Glob patterns are now deprecated.
4091
4092 Compatibility Notes
4093 -------------------
4094
4095 - [Functions with `'static` in their return types will now not be as usable as
4096   if they were using lifetime parameters instead.][42417]
4097 - [The reimplementation of `{f32, f64}::is_sign_{negative, positive}` now
4098   takes the sign of NaN into account where previously didn't.][42430]
4099
4100 [42033]: https://github.com/rust-lang/rust/pull/42033
4101 [42155]: https://github.com/rust-lang/rust/pull/42155
4102 [42271]: https://github.com/rust-lang/rust/pull/42271
4103 [42397]: https://github.com/rust-lang/rust/pull/42397
4104 [42417]: https://github.com/rust-lang/rust/pull/42417
4105 [42430]: https://github.com/rust-lang/rust/pull/42430
4106 [42431]: https://github.com/rust-lang/rust/pull/42431
4107 [42533]: https://github.com/rust-lang/rust/pull/42533
4108 [42571]: https://github.com/rust-lang/rust/pull/42571
4109 [42613]: https://github.com/rust-lang/rust/pull/42613
4110 [42799]: https://github.com/rust-lang/rust/pull/42799
4111 [42807]: https://github.com/rust-lang/rust/pull/42807
4112 [42809]: https://github.com/rust-lang/rust/pull/42809
4113 [42822]: https://github.com/rust-lang/rust/pull/42822
4114 [42826]: https://github.com/rust-lang/rust/pull/42826
4115 [42854]: https://github.com/rust-lang/rust/pull/42854
4116 [42913]: https://github.com/rust-lang/rust/pull/42913
4117 [42999]: https://github.com/rust-lang/rust/pull/42999
4118 [43011]: https://github.com/rust-lang/rust/pull/43011
4119 [43015]: https://github.com/rust-lang/rust/pull/43015
4120 [43072]: https://github.com/rust-lang/rust/pull/43072
4121 [43077]: https://github.com/rust-lang/rust/pull/43077
4122 [43097]: https://github.com/rust-lang/rust/pull/43097
4123 [43099]: https://github.com/rust-lang/rust/pull/43099
4124 [43170]: https://github.com/rust-lang/rust/pull/43170
4125 [43178]: https://github.com/rust-lang/rust/pull/43178
4126 [43185]: https://github.com/rust-lang/rust/pull/43185
4127 [43228]: https://github.com/rust-lang/rust/pull/43228
4128 [cargo/3978]: https://github.com/rust-lang/cargo/pull/3978
4129 [cargo/4214]: https://github.com/rust-lang/cargo/pull/4214
4130 [cargo/4229]: https://github.com/rust-lang/cargo/pull/4229
4131 [cargo/4248]: https://github.com/rust-lang/cargo/pull/4248
4132 [cargo/4259]: https://github.com/rust-lang/cargo/pull/4259
4133 [cargo/4270]: https://github.com/rust-lang/cargo/pull/4270
4134 [`CStr::into_c_string`]: https://doc.rust-lang.org/std/ffi/struct.CStr.html#method.into_c_string
4135 [`CString::as_c_str`]: https://doc.rust-lang.org/std/ffi/struct.CString.html#method.as_c_str
4136 [`CString::into_boxed_c_str`]: https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str
4137 [`Chain::get_mut`]: https://doc.rust-lang.org/std/io/struct.Chain.html#method.get_mut
4138 [`Chain::get_ref`]: https://doc.rust-lang.org/std/io/struct.Chain.html#method.get_ref
4139 [`Chain::into_inner`]: https://doc.rust-lang.org/std/io/struct.Chain.html#method.into_inner
4140 [`Option::get_or_insert_with`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.get_or_insert_with
4141 [`Option::get_or_insert`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.get_or_insert
4142 [`OsStr::into_os_string`]: https://doc.rust-lang.org/std/ffi/struct.OsStr.html#method.into_os_string
4143 [`OsString::into_boxed_os_str`]: https://doc.rust-lang.org/std/ffi/struct.OsString.html#method.into_boxed_os_str
4144 [`Take::get_mut`]: https://doc.rust-lang.org/std/io/struct.Take.html#method.get_mut
4145 [`Take::get_ref`]: https://doc.rust-lang.org/std/io/struct.Take.html#method.get_ref
4146 [`Utf8Error::error_len`]: https://doc.rust-lang.org/std/str/struct.Utf8Error.html#method.error_len
4147 [`char::EscapeDebug`]: https://doc.rust-lang.org/std/char/struct.EscapeDebug.html
4148 [`char::escape_debug`]: https://doc.rust-lang.org/std/primitive.char.html#method.escape_debug
4149 [`compile_error!`]: https://doc.rust-lang.org/std/macro.compile_error.html
4150 [`f32::from_bits`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_bits
4151 [`f32::to_bits`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_bits
4152 [`f64::from_bits`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_bits
4153 [`f64::to_bits`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_bits
4154 [`mem::ManuallyDrop`]: https://doc.rust-lang.org/std/mem/union.ManuallyDrop.html
4155 [`slice::sort_unstable_by_key`]: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_unstable_by_key
4156 [`slice::sort_unstable_by`]: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_unstable_by
4157 [`slice::sort_unstable`]: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_unstable
4158 [`str::from_boxed_utf8_unchecked`]: https://doc.rust-lang.org/std/str/fn.from_boxed_utf8_unchecked.html
4159 [`str::as_bytes_mut`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_bytes_mut
4160 [`str::from_utf8_mut`]: https://doc.rust-lang.org/std/str/fn.from_utf8_mut.html
4161 [`str::from_utf8_unchecked_mut`]: https://doc.rust-lang.org/std/str/fn.from_utf8_unchecked_mut.html
4162 [`str::get_mut`]: https://doc.rust-lang.org/std/primitive.str.html#method.get_mut
4163 [`str::get_unchecked_mut`]: https://doc.rust-lang.org/std/primitive.str.html#method.get_unchecked_mut
4164 [`str::get_unchecked`]: https://doc.rust-lang.org/std/primitive.str.html#method.get_unchecked
4165 [`str::get`]: https://doc.rust-lang.org/std/primitive.str.html#method.get
4166 [`str::into_boxed_bytes`]: https://doc.rust-lang.org/std/primitive.str.html#method.into_boxed_bytes
4167
4168
4169 Version 1.19.0 (2017-07-20)
4170 ===========================
4171
4172 Language
4173 --------
4174
4175 - [Numeric fields can now be used for creating tuple structs.][41145] [RFC 1506]
4176   For example `struct Point(u32, u32); let x = Point { 0: 7, 1: 0 };`.
4177 - [Macro recursion limit increased to 1024 from 64.][41676]
4178 - [Added lint for detecting unused macros.][41907]
4179 - [`loop` can now return a value with `break`.][42016] [RFC 1624]
4180   For example: `let x = loop { break 7; };`
4181 - [C compatible `union`s are now available.][42068] [RFC 1444] They can only
4182   contain `Copy` types and cannot have a `Drop` implementation.
4183   Example: `union Foo { bar: u8, baz: usize }`
4184 - [Non capturing closures can now be coerced into `fn`s,][42162] [RFC 1558]
4185   Example: `let foo: fn(u8) -> u8 = |v: u8| { v };`
4186
4187 Compiler
4188 --------
4189
4190 - [Add support for bootstrapping the Rust compiler toolchain on Android.][41370]
4191 - [Change `arm-linux-androideabi` to correspond to the `armeabi`
4192   official ABI.][41656] If you wish to continue targeting the `armeabi-v7a` ABI
4193   you should use `--target armv7-linux-androideabi`.
4194 - [Fixed ICE when removing a source file between compilation sessions.][41873]
4195 - [Minor optimisation of string operations.][42037]
4196 - [Compiler error message is now `aborting due to previous error(s)` instead of
4197   `aborting due to N previous errors`][42150] This was previously inaccurate and
4198   would only count certain kinds of errors.
4199 - [The compiler now supports Visual Studio 2017][42225]
4200 - [The compiler is now built against LLVM 4.0.1 by default][42948]
4201 - [Added a lot][42264] of [new error codes][42302]
4202 - [Added `target-feature=+crt-static` option][37406] [RFC 1721] Which allows
4203   libraries with C Run-time Libraries(CRT) to be statically linked.
4204 - [Fixed various ARM codegen bugs][42740]
4205
4206 Libraries
4207 ---------
4208
4209 - [`String` now implements `FromIterator<Cow<'a, str>>` and
4210   `Extend<Cow<'a, str>>`][41449]
4211 - [`Vec` now implements `From<&mut [T]>`][41530]
4212 - [`Box<[u8]>` now implements `From<Box<str>>`][41258]
4213 - [`SplitWhitespace` now implements `Clone`][41659]
4214 - [`[u8]::reverse` is now 5x faster and `[u16]::reverse` is now
4215   1.5x faster][41764]
4216 - [`eprint!` and `eprintln!` macros added to prelude.][41192] Same as the `print!`
4217   macros, but for printing to stderr.
4218
4219 Stabilized APIs
4220 ---------------
4221
4222 - [`OsString::shrink_to_fit`]
4223 - [`cmp::Reverse`]
4224 - [`Command::envs`]
4225 - [`thread::ThreadId`]
4226
4227 Cargo
4228 -----
4229
4230 - [Build scripts can now add environment variables to the environment
4231   the crate is being compiled in.
4232   Example: `println!("cargo:rustc-env=FOO=bar");`][cargo/3929]
4233 - [Subcommands now replace the current process rather than spawning a new
4234   child process][cargo/3970]
4235 - [Workspace members can now accept glob file patterns][cargo/3979]
4236 - [Added `--all` flag to the `cargo bench` subcommand to run benchmarks of all
4237   the members in a given workspace.][cargo/3988]
4238 - [Updated `libssh2-sys` to 0.2.6][cargo/4008]
4239 - [Target directory path is now in the cargo metadata][cargo/4022]
4240 - [Cargo no longer checks out a local working directory for the
4241   crates.io index][cargo/4026] This should provide smaller file size for the
4242   registry, and improve cloning times, especially on Windows machines.
4243 - [Added an `--exclude` option for excluding certain packages when using the
4244   `--all` option][cargo/4031]
4245 - [Cargo will now automatically retry when receiving a 5xx error
4246   from crates.io][cargo/4032]
4247 - [The `--features` option now accepts multiple comma or space
4248   delimited values.][cargo/4084]
4249 - [Added support for custom target specific runners][cargo/3954]
4250
4251 Misc
4252 ----
4253
4254 - [Added `rust-windbg.cmd`][39983] for loading rust `.natvis` files in the
4255   Windows Debugger.
4256 - [Rust will now release XZ compressed packages][rust-installer/57]
4257 - [rustup will now prefer to download rust packages with
4258   XZ compression][rustup/1100] over GZip packages.
4259 - [Added the ability to escape `#` in rust documentation][41785] By adding
4260   additional `#`'s ie. `##` is now `#`
4261
4262 Compatibility Notes
4263 -------------------
4264
4265 - [`MutexGuard<T>` may only be `Sync` if `T` is `Sync`.][41624]
4266 - [`-Z` flags are now no longer allowed to be used on the stable
4267   compiler.][41751] This has been a warning for a year previous to this.
4268 - [As a result of the `-Z` flag change, the `cargo-check` plugin no
4269   longer works][42844]. Users should migrate to the built-in `check`
4270   command, which has been available since 1.16.
4271 - [Ending a float literal with `._` is now a hard error.
4272   Example: `42._` .][41946]
4273 - [Any use of a private `extern crate` outside of its module is now a
4274   hard error.][36886] This was previously a warning.
4275 - [`use ::self::foo;` is now a hard error.][36888] `self` paths are always
4276   relative while the `::` prefix makes a path absolute, but was ignored and the
4277   path was relative regardless.
4278 - [Floating point constants in match patterns is now a hard error][36890]
4279   This was previously a warning.
4280 - [Struct or enum constants that don't derive `PartialEq` & `Eq` used
4281   match patterns is now a hard error][36891] This was previously a warning.
4282 - [Lifetimes named `'_` are no longer allowed.][36892] This was previously
4283   a warning.
4284 - [From the pound escape, lines consisting of multiple `#`s are
4285   now visible][41785]
4286 - [It is an error to re-export private enum variants][42460]. This is
4287   known to break a number of crates that depend on an older version of
4288   mustache.
4289 - [On Windows, if `VCINSTALLDIR` is set incorrectly, `rustc` will try
4290   to use it to find the linker, and the build will fail where it did
4291   not previously][42607]
4292
4293 [36886]: https://github.com/rust-lang/rust/issues/36886
4294 [36888]: https://github.com/rust-lang/rust/issues/36888
4295 [36890]: https://github.com/rust-lang/rust/issues/36890
4296 [36891]: https://github.com/rust-lang/rust/issues/36891
4297 [36892]: https://github.com/rust-lang/rust/issues/36892
4298 [37406]: https://github.com/rust-lang/rust/issues/37406
4299 [39983]: https://github.com/rust-lang/rust/pull/39983
4300 [41145]: https://github.com/rust-lang/rust/pull/41145
4301 [41192]: https://github.com/rust-lang/rust/pull/41192
4302 [41258]: https://github.com/rust-lang/rust/pull/41258
4303 [41370]: https://github.com/rust-lang/rust/pull/41370
4304 [41449]: https://github.com/rust-lang/rust/pull/41449
4305 [41530]: https://github.com/rust-lang/rust/pull/41530
4306 [41624]: https://github.com/rust-lang/rust/pull/41624
4307 [41656]: https://github.com/rust-lang/rust/pull/41656
4308 [41659]: https://github.com/rust-lang/rust/pull/41659
4309 [41676]: https://github.com/rust-lang/rust/pull/41676
4310 [41751]: https://github.com/rust-lang/rust/pull/41751
4311 [41764]: https://github.com/rust-lang/rust/pull/41764
4312 [41785]: https://github.com/rust-lang/rust/pull/41785
4313 [41873]: https://github.com/rust-lang/rust/pull/41873
4314 [41907]: https://github.com/rust-lang/rust/pull/41907
4315 [41946]: https://github.com/rust-lang/rust/pull/41946
4316 [42016]: https://github.com/rust-lang/rust/pull/42016
4317 [42037]: https://github.com/rust-lang/rust/pull/42037
4318 [42068]: https://github.com/rust-lang/rust/pull/42068
4319 [42150]: https://github.com/rust-lang/rust/pull/42150
4320 [42162]: https://github.com/rust-lang/rust/pull/42162
4321 [42225]: https://github.com/rust-lang/rust/pull/42225
4322 [42264]: https://github.com/rust-lang/rust/pull/42264
4323 [42302]: https://github.com/rust-lang/rust/pull/42302
4324 [42460]: https://github.com/rust-lang/rust/issues/42460
4325 [42607]: https://github.com/rust-lang/rust/issues/42607
4326 [42740]: https://github.com/rust-lang/rust/pull/42740
4327 [42844]: https://github.com/rust-lang/rust/issues/42844
4328 [42948]: https://github.com/rust-lang/rust/pull/42948
4329 [RFC 1444]: https://github.com/rust-lang/rfcs/pull/1444
4330 [RFC 1506]: https://github.com/rust-lang/rfcs/pull/1506
4331 [RFC 1558]: https://github.com/rust-lang/rfcs/pull/1558
4332 [RFC 1624]: https://github.com/rust-lang/rfcs/pull/1624
4333 [RFC 1721]: https://github.com/rust-lang/rfcs/pull/1721
4334 [`Command::envs`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.envs
4335 [`OsString::shrink_to_fit`]: https://doc.rust-lang.org/std/ffi/struct.OsString.html#method.shrink_to_fit
4336 [`cmp::Reverse`]: https://doc.rust-lang.org/std/cmp/struct.Reverse.html
4337 [`thread::ThreadId`]: https://doc.rust-lang.org/std/thread/struct.ThreadId.html
4338 [cargo/3929]: https://github.com/rust-lang/cargo/pull/3929
4339 [cargo/3954]: https://github.com/rust-lang/cargo/pull/3954
4340 [cargo/3970]: https://github.com/rust-lang/cargo/pull/3970
4341 [cargo/3979]: https://github.com/rust-lang/cargo/pull/3979
4342 [cargo/3988]: https://github.com/rust-lang/cargo/pull/3988
4343 [cargo/4008]: https://github.com/rust-lang/cargo/pull/4008
4344 [cargo/4022]: https://github.com/rust-lang/cargo/pull/4022
4345 [cargo/4026]: https://github.com/rust-lang/cargo/pull/4026
4346 [cargo/4031]: https://github.com/rust-lang/cargo/pull/4031
4347 [cargo/4032]: https://github.com/rust-lang/cargo/pull/4032
4348 [cargo/4084]: https://github.com/rust-lang/cargo/pull/4084
4349 [rust-installer/57]: https://github.com/rust-lang/rust-installer/pull/57
4350 [rustup/1100]: https://github.com/rust-lang-nursery/rustup.rs/pull/1100
4351
4352
4353 Version 1.18.0 (2017-06-08)
4354 ===========================
4355
4356 Language
4357 --------
4358
4359 - [Stabilize pub(restricted)][40556] `pub` can now accept a module path to
4360   make the item visible to just that module tree. Also accepts the keyword
4361   `crate` to make something public to the whole crate but not users of the
4362   library. Example: `pub(crate) mod utils;`. [RFC 1422].
4363 - [Stabilize `#![windows_subsystem]` attribute][40870] conservative exposure of the
4364   `/SUBSYSTEM` linker flag on Windows platforms. [RFC 1665].
4365 - [Refactor of trait object type parsing][40043] Now `ty` in macros can accept
4366   types like `Write + Send`, trailing `+` are now supported in trait objects,
4367   and better error reporting for trait objects starting with `?Sized`.
4368 - [0e+10 is now a valid floating point literal][40589]
4369 - [Now warns if you bind a lifetime parameter to 'static][40734]
4370 - [Tuples, Enum variant fields, and structs with no `repr` attribute or with
4371   `#[repr(Rust)]` are reordered to minimize padding and produce a smaller
4372   representation in some cases.][40377]
4373
4374 Compiler
4375 --------
4376
4377 - [rustc can now emit mir with `--emit mir`][39891]
4378 - [Improved LLVM IR for trivial functions][40367]
4379 - [Added explanation for E0090(Wrong number of lifetimes are supplied)][40723]
4380 - [rustc compilation is now 15%-20% faster][41469] Thanks to optimisation
4381   opportunities found through profiling
4382 - [Improved backtrace formatting when panicking][38165]
4383
4384 Libraries
4385 ---------
4386
4387 - [Specialized `Vec::from_iter` being passed `vec::IntoIter`][40731] if the
4388   iterator hasn't been advanced the original `Vec` is reassembled with no actual
4389   iteration or reallocation.
4390 - [Simplified HashMap Bucket interface][40561] provides performance
4391   improvements for iterating and cloning.
4392 - [Specialize Vec::from_elem to use calloc][40409]
4393 - [Fixed Race condition in fs::create_dir_all][39799]
4394 - [No longer caching stdio on Windows][40516]
4395 - [Optimized insertion sort in slice][40807] insertion sort in some cases
4396   2.50%~ faster and in one case now 12.50% faster.
4397 - [Optimized `AtomicBool::fetch_nand`][41143]
4398
4399 Stabilized APIs
4400 ---------------
4401
4402 - [`Child::try_wait`]
4403 - [`HashMap::retain`]
4404 - [`HashSet::retain`]
4405 - [`PeekMut::pop`]
4406 - [`TcpStream::peek`]
4407 - [`UdpSocket::peek`]
4408 - [`UdpSocket::peek_from`]
4409
4410 Cargo
4411 -----
4412
4413 - [Added partial Pijul support][cargo/3842] Pijul is a version control system in Rust.
4414   You can now create new cargo projects with Pijul using `cargo new --vcs pijul`
4415 - [Now always emits build script warnings for crates that fail to build][cargo/3847]
4416 - [Added Android build support][cargo/3885]
4417 - [Added `--bins` and `--tests` flags][cargo/3901] now you can build all programs
4418   of a certain type, for example `cargo build --bins` will build all
4419   binaries.
4420 - [Added support for haiku][cargo/3952]
4421
4422 Misc
4423 ----
4424
4425 - [rustdoc can now use pulldown-cmark with the `--enable-commonmark` flag][40338]
4426 - [Added rust-windbg script for better debugging on Windows][39983]
4427 - [Rust now uses the official cross compiler for NetBSD][40612]
4428 - [rustdoc now accepts `#` at the start of files][40828]
4429 - [Fixed jemalloc support for musl][41168]
4430
4431 Compatibility Notes
4432 -------------------
4433
4434 - [Changes to how the `0` flag works in format!][40241] Padding zeroes are now
4435   always placed after the sign if it exists and before the digits. With the `#`
4436   flag the zeroes are placed after the prefix and before the digits.
4437 - [Due to the struct field optimisation][40377], using `transmute` on structs
4438   that have no `repr` attribute or `#[repr(Rust)]` will no longer work. This has
4439   always been undefined behavior, but is now more likely to break in practice.
4440 - [The refactor of trait object type parsing][40043] fixed a bug where `+` was
4441   receiving the wrong priority parsing things like `&for<'a> Tr<'a> + Send` as
4442   `&(for<'a> Tr<'a> + Send)` instead of `(&for<'a> Tr<'a>) + Send`
4443 - [Overlapping inherent `impl`s are now a hard error][40728]
4444 - [`PartialOrd` and `Ord` must agree on the ordering.][41270]
4445 - [`rustc main.rs -o out --emit=asm,llvm-ir`][41085] Now will output
4446   `out.asm` and `out.ll` instead of only one of the filetypes.
4447 - [ calling a function that returns `Self` will no longer work][41805] when
4448   the size of `Self` cannot be statically determined.
4449 - [rustc now builds with a "pthreads" flavour of MinGW for Windows GNU][40805]
4450   this has caused a few regressions namely:
4451
4452   - Changed the link order of local static/dynamic libraries (respecting the
4453     order on given rather than having the compiler reorder).
4454   - Changed how MinGW is linked, native code linked to dynamic libraries
4455     may require manually linking to the gcc support library (for the native
4456     code itself)
4457
4458 [38165]: https://github.com/rust-lang/rust/pull/38165
4459 [39799]: https://github.com/rust-lang/rust/pull/39799
4460 [39891]: https://github.com/rust-lang/rust/pull/39891
4461 [39983]: https://github.com/rust-lang/rust/pull/39983
4462 [40043]: https://github.com/rust-lang/rust/pull/40043
4463 [40241]: https://github.com/rust-lang/rust/pull/40241
4464 [40338]: https://github.com/rust-lang/rust/pull/40338
4465 [40367]: https://github.com/rust-lang/rust/pull/40367
4466 [40377]: https://github.com/rust-lang/rust/pull/40377
4467 [40409]: https://github.com/rust-lang/rust/pull/40409
4468 [40516]: https://github.com/rust-lang/rust/pull/40516
4469 [40556]: https://github.com/rust-lang/rust/pull/40556
4470 [40561]: https://github.com/rust-lang/rust/pull/40561
4471 [40589]: https://github.com/rust-lang/rust/pull/40589
4472 [40612]: https://github.com/rust-lang/rust/pull/40612
4473 [40723]: https://github.com/rust-lang/rust/pull/40723
4474 [40728]: https://github.com/rust-lang/rust/pull/40728
4475 [40731]: https://github.com/rust-lang/rust/pull/40731
4476 [40734]: https://github.com/rust-lang/rust/pull/40734
4477 [40805]: https://github.com/rust-lang/rust/pull/40805
4478 [40807]: https://github.com/rust-lang/rust/pull/40807
4479 [40828]: https://github.com/rust-lang/rust/pull/40828
4480 [40870]: https://github.com/rust-lang/rust/pull/40870
4481 [41085]: https://github.com/rust-lang/rust/pull/41085
4482 [41143]: https://github.com/rust-lang/rust/pull/41143
4483 [41168]: https://github.com/rust-lang/rust/pull/41168
4484 [41270]: https://github.com/rust-lang/rust/issues/41270
4485 [41469]: https://github.com/rust-lang/rust/pull/41469
4486 [41805]: https://github.com/rust-lang/rust/issues/41805
4487 [RFC 1422]: https://github.com/rust-lang/rfcs/blob/master/text/1422-pub-restricted.md
4488 [RFC 1665]: https://github.com/rust-lang/rfcs/blob/master/text/1665-windows-subsystem.md
4489 [`Child::try_wait`]: https://doc.rust-lang.org/std/process/struct.Child.html#method.try_wait
4490 [`HashMap::retain`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.retain
4491 [`HashSet::retain`]: https://doc.rust-lang.org/std/collections/struct.HashSet.html#method.retain
4492 [`PeekMut::pop`]: https://doc.rust-lang.org/std/collections/binary_heap/struct.PeekMut.html#method.pop
4493 [`TcpStream::peek`]: https://doc.rust-lang.org/std/net/struct.TcpStream.html#method.peek
4494 [`UdpSocket::peek_from`]: https://doc.rust-lang.org/std/net/struct.UdpSocket.html#method.peek_from
4495 [`UdpSocket::peek`]: https://doc.rust-lang.org/std/net/struct.UdpSocket.html#method.peek
4496 [cargo/3842]: https://github.com/rust-lang/cargo/pull/3842
4497 [cargo/3847]: https://github.com/rust-lang/cargo/pull/3847
4498 [cargo/3885]: https://github.com/rust-lang/cargo/pull/3885
4499 [cargo/3901]: https://github.com/rust-lang/cargo/pull/3901
4500 [cargo/3952]: https://github.com/rust-lang/cargo/pull/3952
4501
4502
4503 Version 1.17.0 (2017-04-27)
4504 ===========================
4505
4506 Language
4507 --------
4508
4509 * [The lifetime of statics and consts defaults to `'static`][39265]. [RFC 1623]
4510 * [Fields of structs may be initialized without duplicating the field/variable
4511   names][39761]. [RFC 1682]
4512 * [`Self` may be included in the `where` clause of `impls`][38864]. [RFC 1647]
4513 * [When coercing to an unsized type lifetimes must be equal][40319]. That is,
4514   there is no subtyping between `T` and `U` when `T: Unsize<U>`. For example,
4515   coercing `&mut [&'a X; N]` to `&mut [&'b X]` requires `'a` be equal to
4516   `'b`. Soundness fix.
4517 * [Values passed to the indexing operator, `[]`, automatically coerce][40166]
4518 * [Static variables may contain references to other statics][40027]
4519
4520 Compiler
4521 --------
4522
4523 * [Exit quickly on only `--emit dep-info`][40336]
4524 * [Make `-C relocation-model` more correctly determine whether the linker
4525   creates a position-independent executable][40245]
4526 * [Add `-C overflow-checks` to directly control whether integer overflow
4527   panics][40037]
4528 * [The rustc type checker now checks items on demand instead of in a single
4529   in-order pass][40008]. This is mostly an internal refactoring in support of
4530   future work, including incremental type checking, but also resolves [RFC
4531   1647], allowing `Self` to appear in `impl` `where` clauses.
4532 * [Optimize vtable loads][39995]
4533 * [Turn off vectorization for Emscripten targets][39990]
4534 * [Provide suggestions for unknown macros imported with `use`][39953]
4535 * [Fix ICEs in path resolution][39939]
4536 * [Strip exception handling code on Emscripten when `panic=abort`][39193]
4537 * [Add clearer error message using `&str + &str`][39116]
4538
4539 Stabilized APIs
4540 ---------------
4541
4542 * [`Arc::into_raw`]
4543 * [`Arc::from_raw`]
4544 * [`Arc::ptr_eq`]
4545 * [`Rc::into_raw`]
4546 * [`Rc::from_raw`]
4547 * [`Rc::ptr_eq`]
4548 * [`Ordering::then`]
4549 * [`Ordering::then_with`]
4550 * [`BTreeMap::range`]
4551 * [`BTreeMap::range_mut`]
4552 * [`collections::Bound`]
4553 * [`process::abort`]
4554 * [`ptr::read_unaligned`]
4555 * [`ptr::write_unaligned`]
4556 * [`Result::expect_err`]
4557 * [`Cell::swap`]
4558 * [`Cell::replace`]
4559 * [`Cell::into_inner`]
4560 * [`Cell::take`]
4561
4562 Libraries
4563 ---------
4564
4565 * [`BTreeMap` and `BTreeSet` can iterate over ranges][27787]
4566 * [`Cell` can store non-`Copy` types][39793]. [RFC 1651]
4567 * [`String` implements `FromIterator<&char>`][40028]
4568 * `Box` [implements][40009] a number of new conversions:
4569   `From<Box<str>> for String`,
4570   `From<Box<[T]>> for Vec<T>`,
4571   `From<Box<CStr>> for CString`,
4572   `From<Box<OsStr>> for OsString`,
4573   `From<Box<Path>> for PathBuf`,
4574   `Into<Box<str>> for String`,
4575   `Into<Box<[T]>> for Vec<T>`,
4576   `Into<Box<CStr>> for CString`,
4577   `Into<Box<OsStr>> for OsString`,
4578   `Into<Box<Path>> for PathBuf`,
4579   `Default for Box<str>`,
4580   `Default for Box<CStr>`,
4581   `Default for Box<OsStr>`,
4582   `From<&CStr> for Box<CStr>`,
4583   `From<&OsStr> for Box<OsStr>`,
4584   `From<&Path> for Box<Path>`
4585 * [`ffi::FromBytesWithNulError` implements `Error` and `Display`][39960]
4586 * [Specialize `PartialOrd<A> for [A] where A: Ord`][39642]
4587 * [Slightly optimize `slice::sort`][39538]
4588 * [Add `ToString` trait specialization for `Cow<'a, str>` and `String`][39440]
4589 * [`Box<[T]>` implements `From<&[T]> where T: Copy`,
4590   `Box<str>` implements `From<&str>`][39438]
4591 * [`IpAddr` implements `From` for various arrays. `SocketAddr` implements
4592   `From<(I, u16)> where I: Into<IpAddr>`][39372]
4593 * [`format!` estimates the needed capacity before writing a string][39356]
4594 * [Support unprivileged symlink creation in Windows][38921]
4595 * [`PathBuf` implements `Default`][38764]
4596 * [Implement `PartialEq<[A]>` for `VecDeque<A>`][38661]
4597 * [`HashMap` resizes adaptively][38368] to guard against DOS attacks
4598   and poor hash functions.
4599
4600 Cargo
4601 -----
4602
4603 * [Add `cargo check --all`][cargo/3731]
4604 * [Add an option to ignore SSL revocation checking][cargo/3699]
4605 * [Add `cargo run --package`][cargo/3691]
4606 * [Add `required_features`][cargo/3667]
4607 * [Assume `build.rs` is a build script][cargo/3664]
4608 * [Find workspace via `workspace_root` link in containing member][cargo/3562]
4609
4610 Misc
4611 ----
4612
4613 * [Documentation is rendered with mdbook instead of the obsolete, in-tree
4614   `rustbook`][39633]
4615 * [The "Unstable Book" documents nightly-only features][ubook]
4616 * [Improve the style of the sidebar in rustdoc output][40265]
4617 * [Configure build correctly on 64-bit CPU's with the armhf ABI][40261]
4618 * [Fix MSP430 breakage due to `i128`][40257]
4619 * [Preliminary Solaris/SPARCv9 support][39903]
4620 * [`rustc` is linked statically on Windows MSVC targets][39837], allowing it to
4621   run without installing the MSVC runtime.
4622 * [`rustdoc --test` includes file names in test names][39788]
4623 * This release includes builds of `std` for `sparc64-unknown-linux-gnu`,
4624   `aarch64-unknown-linux-fuchsia`, and `x86_64-unknown-linux-fuchsia`.
4625 * [Initial support for `aarch64-unknown-freebsd`][39491]
4626 * [Initial support for `i686-unknown-netbsd`][39426]
4627 * [This release no longer includes the old makefile build system][39431]. Rust
4628   is built with a custom build system, written in Rust, and with Cargo.
4629 * [Add Debug implementations for libcollection structs][39002]
4630 * [`TypeId` implements `PartialOrd` and `Ord`][38981]
4631 * [`--test-threads=0` produces an error][38945]
4632 * [`rustup` installs documentation by default][40526]
4633 * [The Rust source includes NatVis visualizations][39843]. These can be used by
4634   WinDbg and Visual Studio to improve the debugging experience.
4635
4636 Compatibility Notes
4637 -------------------
4638
4639 * [Rust 1.17 does not correctly detect the MSVC 2017 linker][38584]. As a
4640   workaround, either use MSVC 2015 or run vcvars.bat.
4641 * [When coercing to an unsized type lifetimes must be equal][40319]. That is,
4642   disallow subtyping between `T` and `U` when `T: Unsize<U>`, e.g. coercing
4643   `&mut [&'a X; N]` to `&mut [&'b X]` requires `'a` be equal to `'b`. Soundness
4644   fix.
4645 * [`format!` and `Display::to_string` panic if an underlying formatting
4646   implementation returns an error][40117]. Previously the error was silently
4647   ignored. It is incorrect for `write_fmt` to return an error when writing
4648   to a string.
4649 * [In-tree crates are verified to be unstable][39851]. Previously, some minor
4650   crates were marked stable and could be accessed from the stable toolchain.
4651 * [Rust git source no longer includes vendored crates][39728]. Those that need
4652   to build with vendored crates should build from release tarballs.
4653 * [Fix inert attributes from `proc_macro_derives`][39572]
4654 * [During crate resolution, rustc prefers a crate in the sysroot if two crates
4655   are otherwise identical][39518]. Unlikely to be encountered outside the Rust
4656   build system.
4657 * [Fixed bugs around how type inference interacts with dead-code][39485]. The
4658   existing code generally ignores the type of dead-code unless a type-hint is
4659   provided; this can cause surprising inference interactions particularly around
4660   defaulting. The new code uniformly ignores the result type of dead-code.
4661 * [Tuple-struct constructors with private fields are no longer visible][38932]
4662 * [Lifetime parameters that do not appear in the arguments are now considered
4663   early-bound][38897], resolving a soundness bug (#[32330]). The
4664   `hr_lifetime_in_assoc_type` future-compatibility lint has been in effect since
4665   April of 2016.
4666 * [rustdoc: fix doctests with non-feature crate attributes][38161]
4667 * [Make transmuting from fn item types to pointer-sized types a hard
4668   error][34198]
4669
4670 [27787]: https://github.com/rust-lang/rust/issues/27787
4671 [32330]: https://github.com/rust-lang/rust/issues/32330
4672 [34198]: https://github.com/rust-lang/rust/pull/34198
4673 [38161]: https://github.com/rust-lang/rust/pull/38161
4674 [38368]: https://github.com/rust-lang/rust/pull/38368
4675 [38584]: https://github.com/rust-lang/rust/issues/38584
4676 [38661]: https://github.com/rust-lang/rust/pull/38661
4677 [38764]: https://github.com/rust-lang/rust/pull/38764
4678 [38864]: https://github.com/rust-lang/rust/issues/38864
4679 [38897]: https://github.com/rust-lang/rust/pull/38897
4680 [38921]: https://github.com/rust-lang/rust/pull/38921
4681 [38932]: https://github.com/rust-lang/rust/pull/38932
4682 [38945]: https://github.com/rust-lang/rust/pull/38945
4683 [38981]: https://github.com/rust-lang/rust/pull/38981
4684 [39002]: https://github.com/rust-lang/rust/pull/39002
4685 [39116]: https://github.com/rust-lang/rust/pull/39116
4686 [39193]: https://github.com/rust-lang/rust/pull/39193
4687 [39265]: https://github.com/rust-lang/rust/pull/39265
4688 [39356]: https://github.com/rust-lang/rust/pull/39356
4689 [39372]: https://github.com/rust-lang/rust/pull/39372
4690 [39426]: https://github.com/rust-lang/rust/pull/39426
4691 [39431]: https://github.com/rust-lang/rust/pull/39431
4692 [39438]: https://github.com/rust-lang/rust/pull/39438
4693 [39440]: https://github.com/rust-lang/rust/pull/39440
4694 [39485]: https://github.com/rust-lang/rust/pull/39485
4695 [39491]: https://github.com/rust-lang/rust/pull/39491
4696 [39518]: https://github.com/rust-lang/rust/pull/39518
4697 [39538]: https://github.com/rust-lang/rust/pull/39538
4698 [39572]: https://github.com/rust-lang/rust/pull/39572
4699 [39633]: https://github.com/rust-lang/rust/pull/39633
4700 [39642]: https://github.com/rust-lang/rust/pull/39642
4701 [39728]: https://github.com/rust-lang/rust/pull/39728
4702 [39761]: https://github.com/rust-lang/rust/pull/39761
4703 [39788]: https://github.com/rust-lang/rust/pull/39788
4704 [39793]: https://github.com/rust-lang/rust/pull/39793
4705 [39837]: https://github.com/rust-lang/rust/pull/39837
4706 [39843]: https://github.com/rust-lang/rust/pull/39843
4707 [39851]: https://github.com/rust-lang/rust/pull/39851
4708 [39903]: https://github.com/rust-lang/rust/pull/39903
4709 [39939]: https://github.com/rust-lang/rust/pull/39939
4710 [39953]: https://github.com/rust-lang/rust/pull/39953
4711 [39960]: https://github.com/rust-lang/rust/pull/39960
4712 [39990]: https://github.com/rust-lang/rust/pull/39990
4713 [39995]: https://github.com/rust-lang/rust/pull/39995
4714 [40008]: https://github.com/rust-lang/rust/pull/40008
4715 [40009]: https://github.com/rust-lang/rust/pull/40009
4716 [40027]: https://github.com/rust-lang/rust/pull/40027
4717 [40028]: https://github.com/rust-lang/rust/pull/40028
4718 [40037]: https://github.com/rust-lang/rust/pull/40037
4719 [40117]: https://github.com/rust-lang/rust/pull/40117
4720 [40166]: https://github.com/rust-lang/rust/pull/40166
4721 [40245]: https://github.com/rust-lang/rust/pull/40245
4722 [40257]: https://github.com/rust-lang/rust/pull/40257
4723 [40261]: https://github.com/rust-lang/rust/pull/40261
4724 [40265]: https://github.com/rust-lang/rust/pull/40265
4725 [40319]: https://github.com/rust-lang/rust/pull/40319
4726 [40336]: https://github.com/rust-lang/rust/pull/40336
4727 [40526]: https://github.com/rust-lang/rust/pull/40526
4728 [RFC 1623]: https://github.com/rust-lang/rfcs/blob/master/text/1623-static.md
4729 [RFC 1647]: https://github.com/rust-lang/rfcs/blob/master/text/1647-allow-self-in-where-clauses.md
4730 [RFC 1651]: https://github.com/rust-lang/rfcs/blob/master/text/1651-movecell.md
4731 [RFC 1682]: https://github.com/rust-lang/rfcs/blob/master/text/1682-field-init-shorthand.md
4732 [`Arc::from_raw`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.from_raw
4733 [`Arc::into_raw`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.into_raw
4734 [`Arc::ptr_eq`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.ptr_eq
4735 [`BTreeMap::range_mut`]: https://doc.rust-lang.org/std/collections/btree_map/struct.BTreeMap.html#method.range_mut
4736 [`BTreeMap::range`]: https://doc.rust-lang.org/std/collections/btree_map/struct.BTreeMap.html#method.range
4737 [`Cell::into_inner`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.into_inner
4738 [`Cell::replace`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.replace
4739 [`Cell::swap`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.swap
4740 [`Cell::take`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.take
4741 [`Ordering::then_with`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.then_with
4742 [`Ordering::then`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.then
4743 [`Rc::from_raw`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.from_raw
4744 [`Rc::into_raw`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.into_raw
4745 [`Rc::ptr_eq`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.ptr_eq
4746 [`Result::expect_err`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.expect_err
4747 [`collections::Bound`]: https://doc.rust-lang.org/std/collections/enum.Bound.html
4748 [`process::abort`]: https://doc.rust-lang.org/std/process/fn.abort.html
4749 [`ptr::read_unaligned`]: https://doc.rust-lang.org/std/ptr/fn.read_unaligned.html
4750 [`ptr::write_unaligned`]: https://doc.rust-lang.org/std/ptr/fn.write_unaligned.html
4751 [cargo/3562]: https://github.com/rust-lang/cargo/pull/3562
4752 [cargo/3664]: https://github.com/rust-lang/cargo/pull/3664
4753 [cargo/3667]: https://github.com/rust-lang/cargo/pull/3667
4754 [cargo/3691]: https://github.com/rust-lang/cargo/pull/3691
4755 [cargo/3699]: https://github.com/rust-lang/cargo/pull/3699
4756 [cargo/3731]: https://github.com/rust-lang/cargo/pull/3731
4757 [mdbook]: https://crates.io/crates/mdbook
4758 [ubook]: https://doc.rust-lang.org/unstable-book/
4759
4760
4761 Version 1.16.0 (2017-03-16)
4762 ===========================
4763
4764 Language
4765 --------
4766
4767 * [The compiler's `dead_code` lint now accounts for type aliases][38051].
4768 * [Uninhabitable enums (those without any variants) no longer permit wildcard
4769   match patterns][38069]
4770 * [Clean up semantics of `self` in an import list][38313]
4771 * [`Self` may appear in `impl` headers][38920]
4772 * [`Self` may appear in struct expressions][39282]
4773
4774 Compiler
4775 --------
4776
4777 * [`rustc` now supports `--emit=metadata`, which causes rustc to emit
4778   a `.rmeta` file containing only crate metadata][38571]. This can be
4779   used by tools like the Rust Language Service to perform
4780   metadata-only builds.
4781 * [Levenshtein based typo suggestions now work in most places, while
4782   previously they worked only for fields and sometimes for local
4783   variables][38927]. Together with the overhaul of "no
4784   resolution"/"unexpected resolution" errors (#[38154]) they result in
4785   large and systematic improvement in resolution diagnostics.
4786 * [Fix `transmute::<T, U>` where `T` requires a bigger alignment than
4787   `U`][38670]
4788 * [rustc: use -Xlinker when specifying an rpath with ',' in it][38798]
4789 * [`rustc` no longer attempts to provide "consider using an explicit
4790   lifetime" suggestions][37057]. They were inaccurate.
4791
4792 Stabilized APIs
4793 ---------------
4794
4795 * [`VecDeque::truncate`]
4796 * [`VecDeque::resize`]
4797 * [`String::insert_str`]
4798 * [`Duration::checked_add`]
4799 * [`Duration::checked_sub`]
4800 * [`Duration::checked_div`]
4801 * [`Duration::checked_mul`]
4802 * [`str::replacen`]
4803 * [`str::repeat`]
4804 * [`SocketAddr::is_ipv4`]
4805 * [`SocketAddr::is_ipv6`]
4806 * [`IpAddr::is_ipv4`]
4807 * [`IpAddr::is_ipv6`]
4808 * [`Vec::dedup_by`]
4809 * [`Vec::dedup_by_key`]
4810 * [`Result::unwrap_or_default`]
4811 * [`<*const T>::wrapping_offset`]
4812 * [`<*mut T>::wrapping_offset`]
4813 * `CommandExt::creation_flags`
4814 * [`File::set_permissions`]
4815 * [`String::split_off`]
4816
4817 Libraries
4818 ---------
4819
4820 * [`[T]::binary_search` and `[T]::binary_search_by_key` now take
4821   their argument by `Borrow` parameter][37761]
4822 * [All public types in std implement `Debug`][38006]
4823 * [`IpAddr` implements `From<Ipv4Addr>` and `From<Ipv6Addr>`][38327]
4824 * [`Ipv6Addr` implements `From<[u16; 8]>`][38131]
4825 * [Ctrl-Z returns from `Stdin.read()` when reading from the console on
4826   Windows][38274]
4827 * [std: Fix partial writes in `LineWriter`][38062]
4828 * [std: Clamp max read/write sizes on Unix][38062]
4829 * [Use more specific panic message for `&str` slicing errors][38066]
4830 * [`TcpListener::set_only_v6` is deprecated][38304]. This
4831   functionality cannot be achieved in std currently.
4832 * [`writeln!`, like `println!`, now accepts a form with no string
4833   or formatting arguments, to just print a newline][38469]
4834 * [Implement `iter::Sum` and `iter::Product` for `Result`][38580]
4835 * [Reduce the size of static data in `std_unicode::tables`][38781]
4836 * [`char::EscapeDebug`, `EscapeDefault`, `EscapeUnicode`,
4837   `CaseMappingIter`, `ToLowercase`, `ToUppercase`, implement
4838   `Display`][38909]
4839 * [`Duration` implements `Sum`][38712]
4840 * [`String` implements `ToSocketAddrs`][39048]
4841
4842 Cargo
4843 -----
4844
4845 * [The `cargo check` command does a type check of a project without
4846   building it][cargo/3296]
4847 * [crates.io will display CI badges from Travis and AppVeyor, if
4848   specified in Cargo.toml][cargo/3546]
4849 * [crates.io will display categories listed in Cargo.toml][cargo/3301]
4850 * [Compilation profiles accept integer values for `debug`, in addition
4851   to `true` and `false`. These are passed to `rustc` as the value to
4852   `-C debuginfo`][cargo/3534]
4853 * [Implement `cargo --version --verbose`][cargo/3604]
4854 * [All builds now output 'dep-info' build dependencies compatible with
4855   make and ninja][cargo/3557]
4856 * [Build all workspace members with `build --all`][cargo/3511]
4857 * [Document all workspace members with `doc --all`][cargo/3515]
4858 * [Path deps outside workspace are not members][cargo/3443]
4859
4860 Misc
4861 ----
4862
4863 * [`rustdoc` has a `--sysroot` argument that, like `rustc`, specifies
4864   the path to the Rust implementation][38589]
4865 * [The `armv7-linux-androideabi` target no longer enables NEON
4866   extensions, per Google's ABI guide][38413]
4867 * [The stock standard library can be compiled for Redox OS][38401]
4868 * [Rust has initial SPARC support][38726]. Tier 3. No builds
4869   available.
4870 * [Rust has experimental support for Nvidia PTX][38559]. Tier 3. No
4871   builds available.
4872 * [Fix backtraces on i686-pc-windows-gnu by disabling FPO][39379]
4873
4874 Compatibility Notes
4875 -------------------
4876
4877 * [Uninhabitable enums (those without any variants) no longer permit wildcard
4878   match patterns][38069]
4879 * In this release, references to uninhabited types can not be
4880   pattern-matched. This was accidentally allowed in 1.15.
4881 * [The compiler's `dead_code` lint now accounts for type aliases][38051].
4882 * [Ctrl-Z returns from `Stdin.read()` when reading from the console on
4883   Windows][38274]
4884 * [Clean up semantics of `self` in an import list][38313]
4885 * Reimplemented lifetime elision. This change was almost entirely compatible
4886   with existing code, but it did close a number of small bugs and loopholes,
4887   as well as being more accepting in some other [cases][41105].
4888
4889 [37057]: https://github.com/rust-lang/rust/pull/37057
4890 [37761]: https://github.com/rust-lang/rust/pull/37761
4891 [38006]: https://github.com/rust-lang/rust/pull/38006
4892 [38051]: https://github.com/rust-lang/rust/pull/38051
4893 [38062]: https://github.com/rust-lang/rust/pull/38062
4894 [38062]: https://github.com/rust-lang/rust/pull/38622
4895 [38066]: https://github.com/rust-lang/rust/pull/38066
4896 [38069]: https://github.com/rust-lang/rust/pull/38069
4897 [38131]: https://github.com/rust-lang/rust/pull/38131
4898 [38154]: https://github.com/rust-lang/rust/pull/38154
4899 [38274]: https://github.com/rust-lang/rust/pull/38274
4900 [38304]: https://github.com/rust-lang/rust/pull/38304
4901 [38313]: https://github.com/rust-lang/rust/pull/38313
4902 [38314]: https://github.com/rust-lang/rust/pull/38314
4903 [38327]: https://github.com/rust-lang/rust/pull/38327
4904 [38401]: https://github.com/rust-lang/rust/pull/38401
4905 [38413]: https://github.com/rust-lang/rust/pull/38413
4906 [38469]: https://github.com/rust-lang/rust/pull/38469
4907 [38559]: https://github.com/rust-lang/rust/pull/38559
4908 [38571]: https://github.com/rust-lang/rust/pull/38571
4909 [38580]: https://github.com/rust-lang/rust/pull/38580
4910 [38589]: https://github.com/rust-lang/rust/pull/38589
4911 [38670]: https://github.com/rust-lang/rust/pull/38670
4912 [38712]: https://github.com/rust-lang/rust/pull/38712
4913 [38726]: https://github.com/rust-lang/rust/pull/38726
4914 [38781]: https://github.com/rust-lang/rust/pull/38781
4915 [38798]: https://github.com/rust-lang/rust/pull/38798
4916 [38909]: https://github.com/rust-lang/rust/pull/38909
4917 [38920]: https://github.com/rust-lang/rust/pull/38920
4918 [38927]: https://github.com/rust-lang/rust/pull/38927
4919 [39048]: https://github.com/rust-lang/rust/pull/39048
4920 [39282]: https://github.com/rust-lang/rust/pull/39282
4921 [39379]: https://github.com/rust-lang/rust/pull/39379
4922 [41105]: https://github.com/rust-lang/rust/issues/41105
4923 [`<*const T>::wrapping_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_offset
4924 [`<*mut T>::wrapping_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_offset
4925 [`Duration::checked_add`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_add
4926 [`Duration::checked_div`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_div
4927 [`Duration::checked_mul`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_mul
4928 [`Duration::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_sub
4929 [`File::set_permissions`]: https://doc.rust-lang.org/std/fs/struct.File.html#method.set_permissions
4930 [`IpAddr::is_ipv4`]: https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_ipv4
4931 [`IpAddr::is_ipv6`]: https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_ipv6
4932 [`Result::unwrap_or_default`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap_or_default
4933 [`SocketAddr::is_ipv4`]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html#method.is_ipv4
4934 [`SocketAddr::is_ipv6`]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html#method.is_ipv6
4935 [`String::insert_str`]: https://doc.rust-lang.org/std/string/struct.String.html#method.insert_str
4936 [`String::split_off`]: https://doc.rust-lang.org/std/string/struct.String.html#method.split_off
4937 [`Vec::dedup_by_key`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.dedup_by_key
4938 [`Vec::dedup_by`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.dedup_by
4939 [`VecDeque::resize`]:  https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.resize
4940 [`VecDeque::truncate`]: https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.truncate
4941 [`str::repeat`]: https://doc.rust-lang.org/std/primitive.str.html#method.repeat
4942 [`str::replacen`]: https://doc.rust-lang.org/std/primitive.str.html#method.replacen
4943 [cargo/3296]: https://github.com/rust-lang/cargo/pull/3296
4944 [cargo/3301]: https://github.com/rust-lang/cargo/pull/3301
4945 [cargo/3443]: https://github.com/rust-lang/cargo/pull/3443
4946 [cargo/3511]: https://github.com/rust-lang/cargo/pull/3511
4947 [cargo/3515]: https://github.com/rust-lang/cargo/pull/3515
4948 [cargo/3534]: https://github.com/rust-lang/cargo/pull/3534
4949 [cargo/3546]: https://github.com/rust-lang/cargo/pull/3546
4950 [cargo/3557]: https://github.com/rust-lang/cargo/pull/3557
4951 [cargo/3604]: https://github.com/rust-lang/cargo/pull/3604
4952 [RFC 1623]: https://github.com/rust-lang/rfcs/blob/master/text/1623-static.md
4953
4954
4955 Version 1.15.1 (2017-02-09)
4956 ===========================
4957
4958 * [Fix IntoIter::as_mut_slice's signature][39466]
4959 * [Compile compiler builtins with `-fPIC` on 32-bit platforms][39523]
4960
4961 [39466]: https://github.com/rust-lang/rust/pull/39466
4962 [39523]: https://github.com/rust-lang/rust/pull/39523
4963
4964
4965 Version 1.15.0 (2017-02-02)
4966 ===========================
4967
4968 Language
4969 --------
4970
4971 * Basic procedural macros allowing custom `#[derive]`, aka "macros 1.1", are
4972   stable. This allows popular code-generating crates like Serde and Diesel to
4973   work ergonomically. [RFC 1681].
4974 * [Tuple structs may be empty. Unary and empty tuple structs may be instantiated
4975   with curly braces][36868]. Part of [RFC 1506].
4976 * [A number of minor changes to name resolution have been activated][37127].
4977   They add up to more consistent semantics, allowing for future evolution of
4978   Rust macros. Specified in [RFC 1560], see its section on ["changes"] for
4979   details of what is different. The breaking changes here have been transitioned
4980   through the [`legacy_imports`] lint since 1.14, with no known regressions.
4981 * [In `macro_rules`, `path` fragments can now be parsed as type parameter
4982   bounds][38279]
4983 * [`?Sized` can be used in `where` clauses][37791]
4984 * [There is now a limit on the size of monomorphized types and it can be
4985   modified with the `#![type_size_limit]` crate attribute, similarly to
4986   the `#![recursion_limit]` attribute][37789]
4987
4988 Compiler
4989 --------
4990
4991 * [On Windows, the compiler will apply dllimport attributes when linking to
4992   extern functions][37973]. Additional attributes and flags can control which
4993   library kind is linked and its name. [RFC 1717].
4994 * [Rust-ABI symbols are no longer exported from cdylibs][38117]
4995 * [The `--test` flag works with procedural macro crates][38107]
4996 * [Fix `extern "aapcs" fn` ABI][37814]
4997 * [The `-C no-stack-check` flag is deprecated][37636]. It does nothing.
4998 * [The `format!` expander recognizes incorrect `printf` and shell-style
4999   formatting directives and suggests the correct format][37613].
5000 * [Only report one error for all unused imports in an import list][37456]
5001
5002 Compiler Performance
5003 --------------------
5004
5005 * [Avoid unnecessary `mk_ty` calls in `Ty::super_fold_with`][37705]
5006 * [Avoid more unnecessary `mk_ty` calls in `Ty::super_fold_with`][37979]
5007 * [Don't clone in `UnificationTable::probe`][37848]
5008 * [Remove `scope_auxiliary` to cut RSS by 10%][37764]
5009 * [Use small vectors in type walker][37760]
5010 * [Macro expansion performance was improved][37701]
5011 * [Change `HirVec<P<T>>` to `HirVec<T>` in `hir::Expr`][37642]
5012 * [Replace FNV with a faster hash function][37229]
5013
5014 Stabilized APIs
5015 ---------------
5016
5017 * [`std::iter::Iterator::min_by`]
5018 * [`std::iter::Iterator::max_by`]
5019 * [`std::os::*::fs::FileExt`]
5020 * [`std::sync::atomic::Atomic*::get_mut`]
5021 * [`std::sync::atomic::Atomic*::into_inner`]
5022 * [`std::vec::IntoIter::as_slice`]
5023 * [`std::vec::IntoIter::as_mut_slice`]
5024 * [`std::sync::mpsc::Receiver::try_iter`]
5025 * [`std::os::unix::process::CommandExt::before_exec`]
5026 * [`std::rc::Rc::strong_count`]
5027 * [`std::rc::Rc::weak_count`]
5028 * [`std::sync::Arc::strong_count`]
5029 * [`std::sync::Arc::weak_count`]
5030 * [`std::char::encode_utf8`]
5031 * [`std::char::encode_utf16`]
5032 * [`std::cell::Ref::clone`]
5033 * [`std::io::Take::into_inner`]
5034
5035 Libraries
5036 ---------
5037
5038 * [The standard sorting algorithm has been rewritten for dramatic performance
5039   improvements][38192]. It is a hybrid merge sort, drawing influences from
5040   Timsort. Previously it was a naive merge sort.
5041 * [`Iterator::nth` no longer has a `Sized` bound][38134]
5042 * [`Extend<&T>` is specialized for `Vec` where `T: Copy`][38182] to improve
5043   performance.
5044 * [`chars().count()` is much faster][37888] and so are [`chars().last()`
5045   and `char_indices().last()`][37882]
5046 * [Fix ARM Objective-C ABI in `std::env::args`][38146]
5047 * [Chinese characters display correctly in `fmt::Debug`][37855]
5048 * [Derive `Default` for `Duration`][37699]
5049 * [Support creation of anonymous pipes on WinXP/2k][37677]
5050 * [`mpsc::RecvTimeoutError` implements `Error`][37527]
5051 * [Don't pass overlapped handles to processes][38835]
5052
5053 Cargo
5054 -----
5055
5056 * [In this release, Cargo build scripts no longer have access to the `OUT_DIR`
5057   environment variable at build time via `env!("OUT_DIR")`][cargo/3368]. They
5058   should instead check the variable at runtime with `std::env`. That the value
5059   was set at build time was a bug, and incorrect when cross-compiling. This
5060   change is known to cause breakage.
5061 * [Add `--all` flag to `cargo test`][cargo/3221]
5062 * [Compile statically against the MSVC CRT][cargo/3363]
5063 * [Mix feature flags into fingerprint/metadata shorthash][cargo/3102]
5064 * [Link OpenSSL statically on OSX][cargo/3311]
5065 * [Apply new fingerprinting to build dir outputs][cargo/3310]
5066 * [Test for bad path overrides with summaries][cargo/3336]
5067 * [Require `cargo install --vers` to take a semver version][cargo/3338]
5068 * [Fix retrying crate downloads for network errors][cargo/3348]
5069 * [Implement string lookup for `build.rustflags` config key][cargo/3356]
5070 * [Emit more info on --message-format=json][cargo/3319]
5071 * [Assume `build.rs` in the same directory as `Cargo.toml` is a build script][cargo/3361]
5072 * [Don't ignore errors in workspace manifest][cargo/3409]
5073 * [Fix `--message-format JSON` when rustc emits non-JSON warnings][cargo/3410]
5074
5075 Tooling
5076 -------
5077
5078 * [Test runners (binaries built with `--test`) now support a `--list` argument
5079   that lists the tests it contains][38185]
5080 * [Test runners now support a `--exact` argument that makes the test filter
5081   match exactly, instead of matching only a substring of the test name][38181]
5082 * [rustdoc supports a `--playground-url` flag][37763]
5083 * [rustdoc provides more details about `#[should_panic]` errors][37749]
5084
5085 Misc
5086 ----
5087
5088 * [The Rust build system is now written in Rust][37817]. The Makefiles may
5089   continue to be used in this release by passing `--disable-rustbuild` to the
5090   configure script, but they will be deleted soon. Note that the new build
5091   system uses a different on-disk layout that will likely affect any scripts
5092   building Rust.
5093 * [Rust supports i686-unknown-openbsd][38086]. Tier 3 support. No testing or
5094   releases.
5095 * [Rust supports the MSP430][37627]. Tier 3 support. No testing or releases.
5096 * [Rust supports the ARMv5TE architecture][37615]. Tier 3 support. No testing or
5097   releases.
5098
5099 Compatibility Notes
5100 -------------------
5101
5102 * [A number of minor changes to name resolution have been activated][37127].
5103   They add up to more consistent semantics, allowing for future evolution of
5104   Rust macros. Specified in [RFC 1560], see its section on ["changes"] for
5105   details of what is different. The breaking changes here have been transitioned
5106   through the [`legacy_imports`] lint since 1.14, with no known regressions.
5107 * [In this release, Cargo build scripts no longer have access to the `OUT_DIR`
5108   environment variable at build time via `env!("OUT_DIR")`][cargo/3368]. They
5109   should instead check the variable at runtime with `std::env`. That the value
5110   was set at build time was a bug, and incorrect when cross-compiling. This
5111   change is known to cause breakage.
5112 * [Higher-ranked lifetimes are no longer allowed to appear _only_ in associated
5113   types][33685]. The [`hr_lifetime_in_assoc_type` lint] has been a warning since
5114   1.10 and is now an error by default. It will become a hard error in the near
5115   future.
5116 * [The semantics relating modules to file system directories are changing in
5117   minor ways][37602]. This is captured in the new `legacy_directory_ownership`
5118   lint, which is a warning in this release, and will become a hard error in the
5119   future.
5120 * [Rust-ABI symbols are no longer exported from cdylibs][38117]
5121 * [Once `Peekable` peeks a `None` it will return that `None` without re-querying
5122   the underlying iterator][37834]
5123
5124 ["changes"]: https://github.com/rust-lang/rfcs/blob/master/text/1560-name-resolution.md#changes-to-name-resolution-rules
5125 [33685]: https://github.com/rust-lang/rust/issues/33685
5126 [36868]: https://github.com/rust-lang/rust/pull/36868
5127 [37127]: https://github.com/rust-lang/rust/pull/37127
5128 [37229]: https://github.com/rust-lang/rust/pull/37229
5129 [37456]: https://github.com/rust-lang/rust/pull/37456
5130 [37527]: https://github.com/rust-lang/rust/pull/37527
5131 [37602]: https://github.com/rust-lang/rust/pull/37602
5132 [37613]: https://github.com/rust-lang/rust/pull/37613
5133 [37615]: https://github.com/rust-lang/rust/pull/37615
5134 [37636]: https://github.com/rust-lang/rust/pull/37636
5135 [37627]: https://github.com/rust-lang/rust/pull/37627
5136 [37642]: https://github.com/rust-lang/rust/pull/37642
5137 [37677]: https://github.com/rust-lang/rust/pull/37677
5138 [37699]: https://github.com/rust-lang/rust/pull/37699
5139 [37701]: https://github.com/rust-lang/rust/pull/37701
5140 [37705]: https://github.com/rust-lang/rust/pull/37705
5141 [37749]: https://github.com/rust-lang/rust/pull/37749
5142 [37760]: https://github.com/rust-lang/rust/pull/37760
5143 [37763]: https://github.com/rust-lang/rust/pull/37763
5144 [37764]: https://github.com/rust-lang/rust/pull/37764
5145 [37789]: https://github.com/rust-lang/rust/pull/37789
5146 [37791]: https://github.com/rust-lang/rust/pull/37791
5147 [37814]: https://github.com/rust-lang/rust/pull/37814
5148 [37817]: https://github.com/rust-lang/rust/pull/37817
5149 [37834]: https://github.com/rust-lang/rust/pull/37834
5150 [37848]: https://github.com/rust-lang/rust/pull/37848
5151 [37855]: https://github.com/rust-lang/rust/pull/37855
5152 [37882]: https://github.com/rust-lang/rust/pull/37882
5153 [37888]: https://github.com/rust-lang/rust/pull/37888
5154 [37973]: https://github.com/rust-lang/rust/pull/37973
5155 [37979]: https://github.com/rust-lang/rust/pull/37979
5156 [38086]: https://github.com/rust-lang/rust/pull/38086
5157 [38107]: https://github.com/rust-lang/rust/pull/38107
5158 [38117]: https://github.com/rust-lang/rust/pull/38117
5159 [38134]: https://github.com/rust-lang/rust/pull/38134
5160 [38146]: https://github.com/rust-lang/rust/pull/38146
5161 [38181]: https://github.com/rust-lang/rust/pull/38181
5162 [38182]: https://github.com/rust-lang/rust/pull/38182
5163 [38185]: https://github.com/rust-lang/rust/pull/38185
5164 [38192]: https://github.com/rust-lang/rust/pull/38192
5165 [38279]: https://github.com/rust-lang/rust/pull/38279
5166 [38835]: https://github.com/rust-lang/rust/pull/38835
5167 [RFC 1492]: https://github.com/rust-lang/rfcs/blob/master/text/1492-dotdot-in-patterns.md
5168 [RFC 1506]: https://github.com/rust-lang/rfcs/blob/master/text/1506-adt-kinds.md
5169 [RFC 1560]: https://github.com/rust-lang/rfcs/blob/master/text/1560-name-resolution.md
5170 [RFC 1681]: https://github.com/rust-lang/rfcs/blob/master/text/1681-macros-1.1.md
5171 [RFC 1717]: https://github.com/rust-lang/rfcs/blob/master/text/1717-dllimport.md
5172 [`hr_lifetime_in_assoc_type` lint]: https://github.com/rust-lang/rust/issues/33685
5173 [`legacy_imports`]: https://github.com/rust-lang/rust/pull/38271
5174 [cargo/3102]: https://github.com/rust-lang/cargo/pull/3102
5175 [cargo/3221]: https://github.com/rust-lang/cargo/pull/3221
5176 [cargo/3310]: https://github.com/rust-lang/cargo/pull/3310
5177 [cargo/3311]: https://github.com/rust-lang/cargo/pull/3311
5178 [cargo/3319]: https://github.com/rust-lang/cargo/pull/3319
5179 [cargo/3336]: https://github.com/rust-lang/cargo/pull/3336
5180 [cargo/3338]: https://github.com/rust-lang/cargo/pull/3338
5181 [cargo/3348]: https://github.com/rust-lang/cargo/pull/3348
5182 [cargo/3356]: https://github.com/rust-lang/cargo/pull/3356
5183 [cargo/3361]: https://github.com/rust-lang/cargo/pull/3361
5184 [cargo/3363]: https://github.com/rust-lang/cargo/pull/3363
5185 [cargo/3368]: https://github.com/rust-lang/cargo/issues/3368
5186 [cargo/3409]: https://github.com/rust-lang/cargo/pull/3409
5187 [cargo/3410]: https://github.com/rust-lang/cargo/pull/3410
5188 [`std::iter::Iterator::min_by`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.min_by
5189 [`std::iter::Iterator::max_by`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.max_by
5190 [`std::os::*::fs::FileExt`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html
5191 [`std::sync::atomic::Atomic*::get_mut`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU8.html#method.get_mut
5192 [`std::sync::atomic::Atomic*::into_inner`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU8.html#method.into_inner
5193 [`std::vec::IntoIter::as_slice`]: https://doc.rust-lang.org/std/vec/struct.IntoIter.html#method.as_slice
5194 [`std::vec::IntoIter::as_mut_slice`]: https://doc.rust-lang.org/std/vec/struct.IntoIter.html#method.as_mut_slice
5195 [`std::sync::mpsc::Receiver::try_iter`]: https://doc.rust-lang.org/std/sync/mpsc/struct.Receiver.html#method.try_iter
5196 [`std::os::unix::process::CommandExt::before_exec`]: https://doc.rust-lang.org/std/os/unix/process/trait.CommandExt.html#tymethod.before_exec
5197 [`std::rc::Rc::strong_count`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.strong_count
5198 [`std::rc::Rc::weak_count`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.weak_count
5199 [`std::sync::Arc::strong_count`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.strong_count
5200 [`std::sync::Arc::weak_count`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.weak_count
5201 [`std::char::encode_utf8`]: https://doc.rust-lang.org/std/primitive.char.html#method.encode_utf8
5202 [`std::char::encode_utf16`]: https://doc.rust-lang.org/std/primitive.char.html#method.encode_utf16
5203 [`std::cell::Ref::clone`]: https://doc.rust-lang.org/std/cell/struct.Ref.html#method.clone
5204 [`std::io::Take::into_inner`]: https://doc.rust-lang.org/std/io/struct.Take.html#method.into_inner
5205
5206
5207 Version 1.14.0 (2016-12-22)
5208 ===========================
5209
5210 Language
5211 --------
5212
5213 * [`..` matches multiple tuple fields in enum variants, structs
5214   and tuples][36843]. [RFC 1492].
5215 * [Safe `fn` items can be coerced to `unsafe fn` pointers][37389]
5216 * [`use *` and `use ::*` both glob-import from the crate root][37367]
5217 * [It's now possible to call a `Vec<Box<Fn()>>` without explicit
5218   dereferencing][36822]
5219
5220 Compiler
5221 --------
5222
5223 * [Mark enums with non-zero discriminant as non-zero][37224]
5224 * [Lower-case `static mut` names are linted like other
5225   statics and consts][37162]
5226 * [Fix ICE on some macros in const integer positions
5227    (e.g. `[u8; m!()]`)][36819]
5228 * [Improve error message and snippet for "did you mean `x`"][36798]
5229 * [Add a panic-strategy field to the target specification][36794]
5230 * [Include LLVM version in `--version --verbose`][37200]
5231
5232 Compile-time Optimizations
5233 --------------------------
5234
5235 * [Improve macro expansion performance][37569]
5236 * [Shrink `Expr_::ExprInlineAsm`][37445]
5237 * [Replace all uses of SHA-256 with BLAKE2b][37439]
5238 * [Reduce the number of bytes hashed by `IchHasher`][37427]
5239 * [Avoid more allocations when compiling html5ever][37373]
5240 * [Use `SmallVector` in `CombineFields::instantiate`][37322]
5241 * [Avoid some allocations in the macro parser][37318]
5242 * [Use a faster deflate setting][37298]
5243 * [Add `ArrayVec` and `AccumulateVec` to reduce heap allocations
5244   during interning of slices][37270]
5245 * [Optimize `write_metadata`][37267]
5246 * [Don't process obligation forest cycles when stalled][37231]
5247 * [Avoid many `CrateConfig` clones][37161]
5248 * [Optimize `Substs::super_fold_with`][37108]
5249 * [Optimize `ObligationForest`'s `NodeState` handling][36993]
5250 * [Speed up `plug_leaks`][36917]
5251
5252 Libraries
5253 ---------
5254
5255 * [`println!()`, with no arguments, prints newline][36825].
5256   Previously, an empty string was required to achieve the same.
5257 * [`Wrapping` impls standard binary and unary operators, as well as
5258    the `Sum` and `Product` iterators][37356]
5259 * [Implement `From<Cow<str>> for String` and `From<Cow<[T]>> for
5260   Vec<T>`][37326]
5261 * [Improve `fold` performance for `chain`, `cloned`, `map`, and
5262   `VecDeque` iterators][37315]
5263 * [Improve `SipHasher` performance on small values][37312]
5264 * [Add Iterator trait TrustedLen to enable better FromIterator /
5265   Extend][37306]
5266 * [Expand `.zip()` specialization to `.map()` and `.cloned()`][37230]
5267 * [`ReadDir` implements `Debug`][37221]
5268 * [Implement `RefUnwindSafe` for atomic types][37178]
5269 * [Specialize `Vec::extend` to `Vec::extend_from_slice`][37094]
5270 * [Avoid allocations in `Decoder::read_str`][37064]
5271 * [`io::Error` implements `From<io::ErrorKind>`][37037]
5272 * [Impl `Debug` for raw pointers to unsized data][36880]
5273 * [Don't reuse `HashMap` random seeds][37470]
5274 * [The internal memory layout of `HashMap` is more cache-friendly, for
5275   significant improvements in some operations][36692]
5276 * [`HashMap` uses less memory on 32-bit architectures][36595]
5277 * [Impl `Add<{str, Cow<str>}>` for `Cow<str>`][36430]
5278
5279 Cargo
5280 -----
5281
5282 * [Expose rustc cfg values to build scripts][cargo/3243]
5283 * [Allow cargo to work with read-only `CARGO_HOME`][cargo/3259]
5284 * [Fix passing --features when testing multiple packages][cargo/3280]
5285 * [Use a single profile set per workspace][cargo/3249]
5286 * [Load `replace` sections from lock files][cargo/3220]
5287 * [Ignore `panic` configuration for test/bench profiles][cargo/3175]
5288
5289 Tooling
5290 -------
5291
5292 * [rustup is the recommended Rust installation method][1.14rustup]
5293 * This release includes host (rustc) builds for Linux on MIPS, PowerPC, and
5294   S390x. These are [tier 2] platforms and may have major defects. Follow the
5295   instructions on the website to install, or add the targets to an existing
5296   installation with `rustup target add`. The new target triples are:
5297   - `mips-unknown-linux-gnu`
5298   - `mipsel-unknown-linux-gnu`
5299   - `mips64-unknown-linux-gnuabi64`
5300   - `mips64el-unknown-linux-gnuabi64 `
5301   - `powerpc-unknown-linux-gnu`
5302   - `powerpc64-unknown-linux-gnu`
5303   - `powerpc64le-unknown-linux-gnu`
5304   - `s390x-unknown-linux-gnu `
5305 * This release includes target (std) builds for ARM Linux running MUSL
5306   libc. These are [tier 2] platforms and may have major defects. Add the
5307   following triples to an existing rustup installation with `rustup target add`:
5308   - `arm-unknown-linux-musleabi`
5309   - `arm-unknown-linux-musleabihf`
5310   - `armv7-unknown-linux-musleabihf`
5311 * This release includes [experimental support for WebAssembly][1.14wasm], via
5312   the `wasm32-unknown-emscripten` target. This target is known to have major
5313   defects. Please test, report, and fix.
5314 * rustup no longer installs documentation by default. Run `rustup
5315   component add rust-docs` to install.
5316 * [Fix line stepping in debugger][37310]
5317 * [Enable line number debuginfo in releases][37280]
5318
5319 Misc
5320 ----
5321
5322 * [Disable jemalloc on aarch64/powerpc/mips][37392]
5323 * [Add support for Fuchsia OS][37313]
5324 * [Detect local-rebuild by only MAJOR.MINOR version][37273]
5325
5326 Compatibility Notes
5327 -------------------
5328
5329 * [A number of forward-compatibility lints used by the compiler
5330   to gradually introduce language changes have been converted
5331   to deny by default][36894]:
5332   - ["use of inaccessible extern crate erroneously allowed"][36886]
5333   - ["type parameter default erroneously allowed in invalid location"][36887]
5334   - ["detects super or self keywords at the beginning of global path"][36888]
5335   - ["two overlapping inherent impls define an item with the same name
5336     were erroneously allowed"][36889]
5337   - ["floating-point constants cannot be used in patterns"][36890]
5338   - ["constants of struct or enum type can only be used in a pattern if
5339      the struct or enum has `#[derive(PartialEq, Eq)]`"][36891]
5340   - ["lifetimes or labels named `'_` were erroneously allowed"][36892]
5341 * [Prohibit patterns in trait methods without bodies][37378]
5342 * [The atomic `Ordering` enum may not be matched exhaustively][37351]
5343 * [Future-proofing `#[no_link]` breaks some obscure cases][37247]
5344 * [The `$crate` macro variable is accepted in fewer locations][37213]
5345 * [Impls specifying extra region requirements beyond the trait
5346   they implement are rejected][37167]
5347 * [Enums may not be unsized][37111]. Unsized enums are intended to
5348   work but never have. For now they are forbidden.
5349 * [Enforce the shadowing restrictions from RFC 1560 for today's macros][36767]
5350
5351 [tier 2]: https://forge.rust-lang.org/platform-support.html
5352 [1.14rustup]: https://internals.rust-lang.org/t/beta-testing-rustup-rs/3316/204
5353 [1.14wasm]: https://users.rust-lang.org/t/compiling-to-the-web-with-rust-and-emscripten/7627
5354 [36430]: https://github.com/rust-lang/rust/pull/36430
5355 [36595]: https://github.com/rust-lang/rust/pull/36595
5356 [36595]: https://github.com/rust-lang/rust/pull/36595
5357 [36692]: https://github.com/rust-lang/rust/pull/36692
5358 [36767]: https://github.com/rust-lang/rust/pull/36767
5359 [36794]: https://github.com/rust-lang/rust/pull/36794
5360 [36798]: https://github.com/rust-lang/rust/pull/36798
5361 [36819]: https://github.com/rust-lang/rust/pull/36819
5362 [36822]: https://github.com/rust-lang/rust/pull/36822
5363 [36825]: https://github.com/rust-lang/rust/pull/36825
5364 [36843]: https://github.com/rust-lang/rust/pull/36843
5365 [36880]: https://github.com/rust-lang/rust/pull/36880
5366 [36886]: https://github.com/rust-lang/rust/issues/36886
5367 [36887]: https://github.com/rust-lang/rust/issues/36887
5368 [36888]: https://github.com/rust-lang/rust/issues/36888
5369 [36889]: https://github.com/rust-lang/rust/issues/36889
5370 [36890]: https://github.com/rust-lang/rust/issues/36890
5371 [36891]: https://github.com/rust-lang/rust/issues/36891
5372 [36892]: https://github.com/rust-lang/rust/issues/36892
5373 [36894]: https://github.com/rust-lang/rust/pull/36894
5374 [36917]: https://github.com/rust-lang/rust/pull/36917
5375 [36993]: https://github.com/rust-lang/rust/pull/36993
5376 [37037]: https://github.com/rust-lang/rust/pull/37037
5377 [37064]: https://github.com/rust-lang/rust/pull/37064
5378 [37094]: https://github.com/rust-lang/rust/pull/37094
5379 [37108]: https://github.com/rust-lang/rust/pull/37108
5380 [37111]: https://github.com/rust-lang/rust/pull/37111
5381 [37161]: https://github.com/rust-lang/rust/pull/37161
5382 [37162]: https://github.com/rust-lang/rust/pull/37162
5383 [37167]: https://github.com/rust-lang/rust/pull/37167
5384 [37178]: https://github.com/rust-lang/rust/pull/37178
5385 [37200]: https://github.com/rust-lang/rust/pull/37200
5386 [37213]: https://github.com/rust-lang/rust/pull/37213
5387 [37221]: https://github.com/rust-lang/rust/pull/37221
5388 [37224]: https://github.com/rust-lang/rust/pull/37224
5389 [37230]: https://github.com/rust-lang/rust/pull/37230
5390 [37231]: https://github.com/rust-lang/rust/pull/37231
5391 [37247]: https://github.com/rust-lang/rust/pull/37247
5392 [37267]: https://github.com/rust-lang/rust/pull/37267
5393 [37270]: https://github.com/rust-lang/rust/pull/37270
5394 [37273]: https://github.com/rust-lang/rust/pull/37273
5395 [37280]: https://github.com/rust-lang/rust/pull/37280
5396 [37298]: https://github.com/rust-lang/rust/pull/37298
5397 [37306]: https://github.com/rust-lang/rust/pull/37306
5398 [37310]: https://github.com/rust-lang/rust/pull/37310
5399 [37312]: https://github.com/rust-lang/rust/pull/37312
5400 [37313]: https://github.com/rust-lang/rust/pull/37313
5401 [37315]: https://github.com/rust-lang/rust/pull/37315
5402 [37318]: https://github.com/rust-lang/rust/pull/37318
5403 [37322]: https://github.com/rust-lang/rust/pull/37322
5404 [37326]: https://github.com/rust-lang/rust/pull/37326
5405 [37351]: https://github.com/rust-lang/rust/pull/37351
5406 [37356]: https://github.com/rust-lang/rust/pull/37356
5407 [37367]: https://github.com/rust-lang/rust/pull/37367
5408 [37373]: https://github.com/rust-lang/rust/pull/37373
5409 [37378]: https://github.com/rust-lang/rust/pull/37378
5410 [37389]: https://github.com/rust-lang/rust/pull/37389
5411 [37392]: https://github.com/rust-lang/rust/pull/37392
5412 [37427]: https://github.com/rust-lang/rust/pull/37427
5413 [37439]: https://github.com/rust-lang/rust/pull/37439
5414 [37445]: https://github.com/rust-lang/rust/pull/37445
5415 [37470]: https://github.com/rust-lang/rust/pull/37470
5416 [37569]: https://github.com/rust-lang/rust/pull/37569
5417 [RFC 1492]: https://github.com/rust-lang/rfcs/blob/master/text/1492-dotdot-in-patterns.md
5418 [cargo/3175]: https://github.com/rust-lang/cargo/pull/3175
5419 [cargo/3220]: https://github.com/rust-lang/cargo/pull/3220
5420 [cargo/3243]: https://github.com/rust-lang/cargo/pull/3243
5421 [cargo/3249]: https://github.com/rust-lang/cargo/pull/3249
5422 [cargo/3259]: https://github.com/rust-lang/cargo/pull/3259
5423 [cargo/3280]: https://github.com/rust-lang/cargo/pull/3280
5424
5425
5426 Version 1.13.0 (2016-11-10)
5427 ===========================
5428
5429 Language
5430 --------
5431
5432 * [Stabilize the `?` operator][36995]. `?` is a simple way to propagate
5433   errors, like the `try!` macro, described in [RFC 0243].
5434 * [Stabilize macros in type position][36014]. Described in [RFC 873].
5435 * [Stabilize attributes on statements][36995]. Described in [RFC 0016].
5436 * [Fix `#[derive]` for empty tuple structs/variants][35728]
5437 * [Fix lifetime rules for 'if' conditions][36029]
5438 * [Avoid loading and parsing unconfigured non-inline modules][36482]
5439
5440 Compiler
5441 --------
5442
5443 * [Add the `-C link-arg` argument][36574]
5444 * [Remove the old AST-based backend from rustc_trans][35764]
5445 * [Don't enable NEON by default on armv7 Linux][35814]
5446 * [Fix debug line number info for macro expansions][35238]
5447 * [Do not emit "class method" debuginfo for types that are not
5448   DICompositeType][36008]
5449 * [Warn about multiple conflicting #[repr] hints][34623]
5450 * [When sizing DST, don't double-count nested struct prefixes][36351]
5451 * [Default RUST_MIN_STACK to 16MiB for now][36505]
5452 * [Improve rlib metadata format][36551]. Reduces rlib size significantly.
5453 * [Reject macros with empty repetitions to avoid infinite loop][36721]
5454 * [Expand macros without recursing to avoid stack overflows][36214]
5455
5456 Diagnostics
5457 -----------
5458
5459 * [Replace macro backtraces with labeled local uses][35702]
5460 * [Improve error message for misplaced doc comments][33922]
5461 * [Buffer unix and lock windows to prevent message interleaving][35975]
5462 * [Update lifetime errors to specifically note temporaries][36171]
5463 * [Special case a few colors for Windows][36178]
5464 * [Suggest `use self` when such an import resolves][36289]
5465 * [Be more specific when type parameter shadows primitive type][36338]
5466 * Many minor improvements
5467
5468 Compile-time Optimizations
5469 --------------------------
5470
5471 * [Compute and cache HIR hashes at beginning][35854]
5472 * [Don't hash types in loan paths][36004]
5473 * [Cache projections in trans][35761]
5474 * [Optimize the parser's last token handling][36527]
5475 * [Only instantiate #[inline] functions in codegen units referencing
5476   them][36524]. This leads to big improvements in cases where crates export
5477   define many inline functions without using them directly.
5478 * [Lazily allocate TypedArena's first chunk][36592]
5479 * [Don't allocate during default HashSet creation][36734]
5480
5481 Stabilized APIs
5482 ---------------
5483
5484 * [`checked_abs`]
5485 * [`wrapping_abs`]
5486 * [`overflowing_abs`]
5487 * [`RefCell::try_borrow`]
5488 * [`RefCell::try_borrow_mut`]
5489
5490 Libraries
5491 ---------
5492
5493 * [Add `assert_ne!` and `debug_assert_ne!`][35074]
5494 * [Make `vec_deque::Drain`, `hash_map::Drain`, and `hash_set::Drain`
5495   covariant][35354]
5496 * [Implement `AsRef<[T]>` for `std::slice::Iter`][35559]
5497 * [Implement `Debug` for `std::vec::IntoIter`][35707]
5498 * [`CString`: avoid excessive growth just to 0-terminate][35871]
5499 * [Implement `CoerceUnsized` for `{Cell, RefCell, UnsafeCell}`][35627]
5500 * [Use arc4rand on FreeBSD][35884]
5501 * [memrchr: Correct aligned offset computation][35969]
5502 * [Improve Demangling of Rust Symbols][36059]
5503 * [Use monotonic time in condition variables][35048]
5504 * [Implement `Debug` for `std::path::{Components,Iter}`][36101]
5505 * [Implement conversion traits for `char`][35755]
5506 * [Fix illegal instruction caused by overflow in channel cloning][36104]
5507 * [Zero first byte of CString on drop][36264]
5508 * [Inherit overflow checks for sum and product][36372]
5509 * [Add missing Eq implementations][36423]
5510 * [Implement `Debug` for `DirEntry`][36631]
5511 * [When `getaddrinfo` returns `EAI_SYSTEM` retrieve actual error from
5512   `errno`][36754]
5513 * [`SipHasher`] is deprecated. Use [`DefaultHasher`].
5514 * [Implement more traits for `std::io::ErrorKind`][35911]
5515 * [Optimize BinaryHeap bounds checking][36072]
5516 * [Work around pointer aliasing issue in `Vec::extend_from_slice`,
5517   `extend_with_element`][36355]
5518 * [Fix overflow checking in unsigned pow()][34942]
5519
5520 Cargo
5521 -----
5522
5523 * This release includes security fixes to both curl and OpenSSL.
5524 * [Fix transitive doctests when panic=abort][cargo/3021]
5525 * [Add --all-features flag to cargo][cargo/3038]
5526 * [Reject path-based dependencies in `cargo package`][cargo/3060]
5527 * [Don't parse the home directory more than once][cargo/3078]
5528 * [Don't try to generate Cargo.lock on empty workspaces][cargo/3092]
5529 * [Update OpenSSL to 1.0.2j][cargo/3121]
5530 * [Add license and license_file to cargo metadata output][cargo/3110]
5531 * [Make crates-io registry URL optional in config; ignore all changes to
5532   source.crates-io][cargo/3089]
5533 * [Don't download dependencies from other platforms][cargo/3123]
5534 * [Build transitive dev-dependencies when needed][cargo/3125]
5535 * [Add support for per-target rustflags in .cargo/config][cargo/3157]
5536 * [Avoid updating registry when adding existing deps][cargo/3144]
5537 * [Warn about path overrides that won't work][cargo/3136]
5538 * [Use workspaces during `cargo install`][cargo/3146]
5539 * [Leak mspdbsrv.exe processes on Windows][cargo/3162]
5540 * [Add --message-format flag][cargo/3000]
5541 * [Pass target environment for rustdoc][cargo/3205]
5542 * [Use `CommandExt::exec` for `cargo run` on Unix][cargo/2818]
5543 * [Update curl and curl-sys][cargo/3241]
5544 * [Call rustdoc test with the correct cfg flags of a package][cargo/3242]
5545
5546 Tooling
5547 -------
5548
5549 * [rustdoc: Add the `--sysroot` argument][36586]
5550 * [rustdoc: Fix a couple of issues with the search results][35655]
5551 * [rustdoc: remove the `!` from macro URLs and titles][35234]
5552 * [gdb: Fix pretty-printing special-cased Rust types][35585]
5553 * [rustdoc: Filter more incorrect methods inherited through Deref][36266]
5554
5555 Misc
5556 ----
5557
5558 * [Remove unmaintained style guide][35124]
5559 * [Add s390x support][36369]
5560 * [Initial work at Haiku OS support][36727]
5561 * [Add mips-uclibc targets][35734]
5562 * [Crate-ify compiler-rt into compiler-builtins][35021]
5563 * [Add rustc version info (git hash + date) to dist tarball][36213]
5564 * Many documentation improvements
5565
5566 Compatibility Notes
5567 -------------------
5568
5569 * [`SipHasher`] is deprecated. Use [`DefaultHasher`].
5570 * [Deny (by default) transmuting from fn item types to pointer-sized
5571   types][34923]. Continuing the long transition to zero-sized fn items,
5572   per [RFC 401].
5573 * [Fix `#[derive]` for empty tuple structs/variants][35728].
5574   Part of [RFC 1506].
5575 * [Issue deprecation warnings for safe accesses to extern statics][36173]
5576 * [Fix lifetime rules for 'if' conditions][36029].
5577 * [Inherit overflow checks for sum and product][36372].
5578 * [Forbid user-defined macros named "macro_rules"][36730].
5579
5580 [33922]: https://github.com/rust-lang/rust/pull/33922
5581 [34623]: https://github.com/rust-lang/rust/pull/34623
5582 [34923]: https://github.com/rust-lang/rust/pull/34923
5583 [34942]: https://github.com/rust-lang/rust/pull/34942
5584 [34982]: https://github.com/rust-lang/rust/pull/34982
5585 [35021]: https://github.com/rust-lang/rust/pull/35021
5586 [35048]: https://github.com/rust-lang/rust/pull/35048
5587 [35074]: https://github.com/rust-lang/rust/pull/35074
5588 [35124]: https://github.com/rust-lang/rust/pull/35124
5589 [35234]: https://github.com/rust-lang/rust/pull/35234
5590 [35238]: https://github.com/rust-lang/rust/pull/35238
5591 [35354]: https://github.com/rust-lang/rust/pull/35354
5592 [35559]: https://github.com/rust-lang/rust/pull/35559
5593 [35585]: https://github.com/rust-lang/rust/pull/35585
5594 [35627]: https://github.com/rust-lang/rust/pull/35627
5595 [35655]: https://github.com/rust-lang/rust/pull/35655
5596 [35702]: https://github.com/rust-lang/rust/pull/35702
5597 [35707]: https://github.com/rust-lang/rust/pull/35707
5598 [35728]: https://github.com/rust-lang/rust/pull/35728
5599 [35734]: https://github.com/rust-lang/rust/pull/35734
5600 [35755]: https://github.com/rust-lang/rust/pull/35755
5601 [35761]: https://github.com/rust-lang/rust/pull/35761
5602 [35764]: https://github.com/rust-lang/rust/pull/35764
5603 [35814]: https://github.com/rust-lang/rust/pull/35814
5604 [35854]: https://github.com/rust-lang/rust/pull/35854
5605 [35871]: https://github.com/rust-lang/rust/pull/35871
5606 [35884]: https://github.com/rust-lang/rust/pull/35884
5607 [35911]: https://github.com/rust-lang/rust/pull/35911
5608 [35969]: https://github.com/rust-lang/rust/pull/35969
5609 [35975]: https://github.com/rust-lang/rust/pull/35975
5610 [36004]: https://github.com/rust-lang/rust/pull/36004
5611 [36008]: https://github.com/rust-lang/rust/pull/36008
5612 [36014]: https://github.com/rust-lang/rust/pull/36014
5613 [36029]: https://github.com/rust-lang/rust/pull/36029
5614 [36059]: https://github.com/rust-lang/rust/pull/36059
5615 [36072]: https://github.com/rust-lang/rust/pull/36072
5616 [36101]: https://github.com/rust-lang/rust/pull/36101
5617 [36104]: https://github.com/rust-lang/rust/pull/36104
5618 [36171]: https://github.com/rust-lang/rust/pull/36171
5619 [36173]: https://github.com/rust-lang/rust/pull/36173
5620 [36178]: https://github.com/rust-lang/rust/pull/36178
5621 [36213]: https://github.com/rust-lang/rust/pull/36213
5622 [36214]: https://github.com/rust-lang/rust/pull/36214
5623 [36264]: https://github.com/rust-lang/rust/pull/36264
5624 [36266]: https://github.com/rust-lang/rust/pull/36266
5625 [36289]: https://github.com/rust-lang/rust/pull/36289
5626 [36338]: https://github.com/rust-lang/rust/pull/36338
5627 [36351]: https://github.com/rust-lang/rust/pull/36351
5628 [36355]: https://github.com/rust-lang/rust/pull/36355
5629 [36369]: https://github.com/rust-lang/rust/pull/36369
5630 [36372]: https://github.com/rust-lang/rust/pull/36372
5631 [36423]: https://github.com/rust-lang/rust/pull/36423
5632 [36482]: https://github.com/rust-lang/rust/pull/36482
5633 [36505]: https://github.com/rust-lang/rust/pull/36505
5634 [36524]: https://github.com/rust-lang/rust/pull/36524
5635 [36527]: https://github.com/rust-lang/rust/pull/36527
5636 [36551]: https://github.com/rust-lang/rust/pull/36551
5637 [36574]: https://github.com/rust-lang/rust/pull/36574
5638 [36586]: https://github.com/rust-lang/rust/pull/36586
5639 [36592]: https://github.com/rust-lang/rust/pull/36592
5640 [36631]: https://github.com/rust-lang/rust/pull/36631
5641 [36639]: https://github.com/rust-lang/rust/pull/36639
5642 [36721]: https://github.com/rust-lang/rust/pull/36721
5643 [36727]: https://github.com/rust-lang/rust/pull/36727
5644 [36730]: https://github.com/rust-lang/rust/pull/36730
5645 [36734]: https://github.com/rust-lang/rust/pull/36734
5646 [36754]: https://github.com/rust-lang/rust/pull/36754
5647 [36995]: https://github.com/rust-lang/rust/pull/36995
5648 [RFC 0016]: https://github.com/rust-lang/rfcs/blob/master/text/0016-more-attributes.md
5649 [RFC 0243]: https://github.com/rust-lang/rfcs/blob/master/text/0243-trait-based-exception-handling.md
5650 [RFC 1506]: https://github.com/rust-lang/rfcs/blob/master/text/1506-adt-kinds.md
5651 [RFC 401]: https://github.com/rust-lang/rfcs/blob/master/text/0401-coercions.md
5652 [RFC 873]: https://github.com/rust-lang/rfcs/blob/master/text/0873-type-macros.md
5653 [cargo/2818]: https://github.com/rust-lang/cargo/pull/2818
5654 [cargo/3000]: https://github.com/rust-lang/cargo/pull/3000
5655 [cargo/3021]: https://github.com/rust-lang/cargo/pull/3021
5656 [cargo/3038]: https://github.com/rust-lang/cargo/pull/3038
5657 [cargo/3060]: https://github.com/rust-lang/cargo/pull/3060
5658 [cargo/3078]: https://github.com/rust-lang/cargo/pull/3078
5659 [cargo/3089]: https://github.com/rust-lang/cargo/pull/3089
5660 [cargo/3092]: https://github.com/rust-lang/cargo/pull/3092
5661 [cargo/3110]: https://github.com/rust-lang/cargo/pull/3110
5662 [cargo/3121]: https://github.com/rust-lang/cargo/pull/3121
5663 [cargo/3123]: https://github.com/rust-lang/cargo/pull/3123
5664 [cargo/3125]: https://github.com/rust-lang/cargo/pull/3125
5665 [cargo/3136]: https://github.com/rust-lang/cargo/pull/3136
5666 [cargo/3144]: https://github.com/rust-lang/cargo/pull/3144
5667 [cargo/3146]: https://github.com/rust-lang/cargo/pull/3146
5668 [cargo/3157]: https://github.com/rust-lang/cargo/pull/3157
5669 [cargo/3162]: https://github.com/rust-lang/cargo/pull/3162
5670 [cargo/3205]: https://github.com/rust-lang/cargo/pull/3205
5671 [cargo/3241]: https://github.com/rust-lang/cargo/pull/3241
5672 [cargo/3242]: https://github.com/rust-lang/cargo/pull/3242
5673 [rustup]: https://www.rustup.rs
5674 [`checked_abs`]: https://doc.rust-lang.org/std/primitive.i32.html#method.checked_abs
5675 [`wrapping_abs`]: https://doc.rust-lang.org/std/primitive.i32.html#method.wrapping_abs
5676 [`overflowing_abs`]: https://doc.rust-lang.org/std/primitive.i32.html#method.overflowing_abs
5677 [`RefCell::try_borrow`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.try_borrow
5678 [`RefCell::try_borrow_mut`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.try_borrow_mut
5679 [`SipHasher`]: https://doc.rust-lang.org/std/hash/struct.SipHasher.html
5680 [`DefaultHasher`]: https://doc.rust-lang.org/std/collections/hash_map/struct.DefaultHasher.html
5681
5682
5683 Version 1.12.1 (2016-10-20)
5684 ===========================
5685
5686 Regression Fixes
5687 ----------------
5688
5689 * [ICE: 'rustc' panicked at 'assertion failed: concrete_substs.is_normalized_for_trans()' #36381][36381]
5690 * [Confusion with double negation and booleans][36856]
5691 * [rustc 1.12.0 fails with SIGSEGV in release mode (syn crate 0.8.0)][36875]
5692 * [Rustc 1.12.0 Windows build of `ethcore` crate fails with LLVM error][36924]
5693 * [1.12.0: High memory usage when linking in release mode with debug info][36926]
5694 * [Corrupted memory after updated to 1.12][36936]
5695 * ["Let NullaryConstructor = something;" causes internal compiler error: "tried to overwrite interned AdtDef"][37026]
5696 * [Fix ICE: inject bitcast if types mismatch for invokes/calls/stores][37112]
5697 * [debuginfo: Handle spread_arg case in MIR-trans in a more stable way.][37153]
5698
5699 [36381]: https://github.com/rust-lang/rust/issues/36381
5700 [36856]: https://github.com/rust-lang/rust/issues/36856
5701 [36875]: https://github.com/rust-lang/rust/issues/36875
5702 [36924]: https://github.com/rust-lang/rust/issues/36924
5703 [36926]: https://github.com/rust-lang/rust/issues/36926
5704 [36936]: https://github.com/rust-lang/rust/issues/36936
5705 [37026]: https://github.com/rust-lang/rust/issues/37026
5706 [37112]: https://github.com/rust-lang/rust/issues/37112
5707 [37153]: https://github.com/rust-lang/rust/issues/37153
5708
5709
5710 Version 1.12.0 (2016-09-29)
5711 ===========================
5712
5713 Highlights
5714 ----------
5715
5716 * [`rustc` translates code to LLVM IR via its own "middle" IR (MIR)](https://github.com/rust-lang/rust/pull/34096).
5717   This translation pass is far simpler than the previous AST->LLVM pass, and
5718   creates opportunities to perform new optimizations directly on the MIR. It
5719   was previously described [on the Rust blog](https://blog.rust-lang.org/2016/04/19/MIR.html).
5720 * [`rustc` presents a new, more readable error format, along with
5721   machine-readable JSON error output for use by IDEs](https://github.com/rust-lang/rust/pull/35401).
5722   Most common editors supporting Rust have been updated to work with it. It was
5723   previously described [on the Rust blog](https://blog.rust-lang.org/2016/08/10/Shape-of-errors-to-come.html).
5724
5725 Compiler
5726 --------
5727
5728 * [`rustc` translates code to LLVM IR via its own "middle" IR (MIR)](https://github.com/rust-lang/rust/pull/34096).
5729   This translation pass is far simpler than the previous AST->LLVM pass, and
5730   creates opportunities to perform new optimizations directly on the MIR. It
5731   was previously described [on the Rust blog](https://blog.rust-lang.org/2016/04/19/MIR.html).
5732 * [Print the Rust target name, not the LLVM target name, with
5733   `--print target-list`](https://github.com/rust-lang/rust/pull/35489)
5734 * [The computation of `TypeId` is correct in some cases where it was previously
5735   producing inconsistent results](https://github.com/rust-lang/rust/pull/35267)
5736 * [The `mips-unknown-linux-gnu` target uses hardware floating point by default](https://github.com/rust-lang/rust/pull/34910)
5737 * [The `rustc` arguments, `--print target-cpus`, `--print target-features`,
5738   `--print relocation-models`, and `--print code-models` print the available
5739   options to the `-C target-cpu`, `-C target-feature`, `-C relocation-model` and
5740   `-C code-model` code generation arguments](https://github.com/rust-lang/rust/pull/34845)
5741 * [`rustc` supports three new MUSL targets on ARM: `arm-unknown-linux-musleabi`,
5742   `arm-unknown-linux-musleabihf`, and `armv7-unknown-linux-musleabihf`](https://github.com/rust-lang/rust/pull/35060).
5743   These targets produce statically-linked binaries. There are no binary release
5744   builds yet though.
5745
5746 Diagnostics
5747 -----------
5748
5749 * [`rustc` presents a new, more readable error format, along with
5750   machine-readable JSON error output for use by IDEs](https://github.com/rust-lang/rust/pull/35401).
5751   Most common editors supporting Rust have been updated to work with it. It was
5752   previously described [on the Rust blog](https://blog.rust-lang.org/2016/08/10/Shape-of-errors-to-come.html).
5753 * [In error descriptions, references are now described in plain English,
5754   instead of as "&-ptr"](https://github.com/rust-lang/rust/pull/35611)
5755 * [In error type descriptions, unknown numeric types are named `{integer}` or
5756   `{float}` instead of `_`](https://github.com/rust-lang/rust/pull/35080)
5757 * [`rustc` emits a clearer error when inner attributes follow a doc comment](https://github.com/rust-lang/rust/pull/34676)
5758
5759 Language
5760 --------
5761
5762 * [`macro_rules!` invocations can be made within `macro_rules!` invocations](https://github.com/rust-lang/rust/pull/34925)
5763 * [`macro_rules!` meta-variables are hygienic](https://github.com/rust-lang/rust/pull/35453)
5764 * [`macro_rules!` `tt` matchers can be reparsed correctly, making them much more
5765   useful](https://github.com/rust-lang/rust/pull/34908)
5766 * [`macro_rules!` `stmt` matchers correctly consume the entire contents when
5767   inside non-braces invocations](https://github.com/rust-lang/rust/pull/34886)
5768 * [Semicolons are properly required as statement delimiters inside
5769   `macro_rules!` invocations](https://github.com/rust-lang/rust/pull/34660)
5770 * [`cfg_attr` works on `path` attributes](https://github.com/rust-lang/rust/pull/34546)
5771
5772 Stabilized APIs
5773 ---------------
5774
5775 * [`Cell::as_ptr`](https://doc.rust-lang.org/std/cell/struct.Cell.html#method.as_ptr)
5776 * [`RefCell::as_ptr`](https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.as_ptr)
5777 * [`IpAddr::is_unspecified`](https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_unspecified)
5778 * [`IpAddr::is_loopback`](https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_loopback)
5779 * [`IpAddr::is_multicast`](https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_multicast)
5780 * [`Ipv4Addr::is_unspecified`](https://doc.rust-lang.org/std/net/struct.Ipv4Addr.html#method.is_unspecified)
5781 * [`Ipv6Addr::octets`](https://doc.rust-lang.org/std/net/struct.Ipv6Addr.html#method.octets)
5782 * [`LinkedList::contains`](https://doc.rust-lang.org/std/collections/linked_list/struct.LinkedList.html#method.contains)
5783 * [`VecDeque::contains`](https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.contains)
5784 * [`ExitStatusExt::from_raw`](https://doc.rust-lang.org/std/os/unix/process/trait.ExitStatusExt.html#tymethod.from_raw).
5785   Both on Unix and Windows.
5786 * [`Receiver::recv_timeout`](https://doc.rust-lang.org/std/sync/mpsc/struct.Receiver.html#method.recv_timeout)
5787 * [`RecvTimeoutError`](https://doc.rust-lang.org/std/sync/mpsc/enum.RecvTimeoutError.html)
5788 * [`BinaryHeap::peek_mut`](https://doc.rust-lang.org/std/collections/binary_heap/struct.BinaryHeap.html#method.peek_mut)
5789 * [`PeekMut`](https://doc.rust-lang.org/std/collections/binary_heap/struct.PeekMut.html)
5790 * [`iter::Product`](https://doc.rust-lang.org/std/iter/trait.Product.html)
5791 * [`iter::Sum`](https://doc.rust-lang.org/std/iter/trait.Sum.html)
5792 * [`OccupiedEntry::remove_entry`](https://doc.rust-lang.org/std/collections/btree_map/struct.OccupiedEntry.html#method.remove_entry)
5793 * [`VacantEntry::into_key`](https://doc.rust-lang.org/std/collections/btree_map/struct.VacantEntry.html#method.into_key)
5794
5795 Libraries
5796 ---------
5797
5798 * [The `format!` macro and friends now allow a single argument to be formatted
5799   in multiple styles](https://github.com/rust-lang/rust/pull/33642)
5800 * [The lifetime bounds on `[T]::binary_search_by` and
5801   `[T]::binary_search_by_key` have been adjusted to be more flexible](https://github.com/rust-lang/rust/pull/34762)
5802 * [`Option` implements `From` for its contained type](https://github.com/rust-lang/rust/pull/34828)
5803 * [`Cell`, `RefCell` and `UnsafeCell` implement `From` for their contained type](https://github.com/rust-lang/rust/pull/35392)
5804 * [`RwLock` panics if the reader count overflows](https://github.com/rust-lang/rust/pull/35378)
5805 * [`vec_deque::Drain`, `hash_map::Drain` and `hash_set::Drain` are covariant](https://github.com/rust-lang/rust/pull/35354)
5806 * [`vec::Drain` and `binary_heap::Drain` are covariant](https://github.com/rust-lang/rust/pull/34951)
5807 * [`Cow<str>` implements `FromIterator` for `char`, `&str` and `String`](https://github.com/rust-lang/rust/pull/35064)
5808 * [Sockets on Linux are correctly closed in subprocesses via `SOCK_CLOEXEC`](https://github.com/rust-lang/rust/pull/34946)
5809 * [`hash_map::Entry`, `hash_map::VacantEntry` and `hash_map::OccupiedEntry`
5810   implement `Debug`](https://github.com/rust-lang/rust/pull/34937)
5811 * [`btree_map::Entry`, `btree_map::VacantEntry` and `btree_map::OccupiedEntry`
5812   implement `Debug`](https://github.com/rust-lang/rust/pull/34885)
5813 * [`String` implements `AddAssign`](https://github.com/rust-lang/rust/pull/34890)
5814 * [Variadic `extern fn` pointers implement the `Clone`, `PartialEq`, `Eq`,
5815   `PartialOrd`, `Ord`, `Hash`, `fmt::Pointer`, and `fmt::Debug` traits](https://github.com/rust-lang/rust/pull/34879)
5816 * [`FileType` implements `Debug`](https://github.com/rust-lang/rust/pull/34757)
5817 * [References to `Mutex` and `RwLock` are unwind-safe](https://github.com/rust-lang/rust/pull/34756)
5818 * [`mpsc::sync_channel` `Receiver`s return any available message before
5819   reporting a disconnect](https://github.com/rust-lang/rust/pull/34731)
5820 * [Unicode definitions have been updated to 9.0](https://github.com/rust-lang/rust/pull/34599)
5821 * [`env` iterators implement `DoubleEndedIterator`](https://github.com/rust-lang/rust/pull/33312)
5822
5823 Cargo
5824 -----
5825
5826 * [Support local mirrors of registries](https://github.com/rust-lang/cargo/pull/2857)
5827 * [Add support for command aliases](https://github.com/rust-lang/cargo/pull/2679)
5828 * [Allow `opt-level="s"` / `opt-level="z"` in profile overrides](https://github.com/rust-lang/cargo/pull/3007)
5829 * [Make `cargo doc --open --target` work as expected](https://github.com/rust-lang/cargo/pull/2988)
5830 * [Speed up noop registry updates](https://github.com/rust-lang/cargo/pull/2974)
5831 * [Update OpenSSL](https://github.com/rust-lang/cargo/pull/2971)
5832 * [Fix `--panic=abort` with plugins](https://github.com/rust-lang/cargo/pull/2954)
5833 * [Always pass `-C metadata` to the compiler](https://github.com/rust-lang/cargo/pull/2946)
5834 * [Fix depending on git repos with workspaces](https://github.com/rust-lang/cargo/pull/2938)
5835 * [Add a `--lib` flag to `cargo new`](https://github.com/rust-lang/cargo/pull/2921)
5836 * [Add `http.cainfo` for custom certs](https://github.com/rust-lang/cargo/pull/2917)
5837 * [Indicate the compilation profile after compiling](https://github.com/rust-lang/cargo/pull/2909)
5838 * [Allow enabling features for dependencies with `--features`](https://github.com/rust-lang/cargo/pull/2876)
5839 * [Add `--jobs` flag to `cargo package`](https://github.com/rust-lang/cargo/pull/2867)
5840 * [Add `--dry-run` to `cargo publish`](https://github.com/rust-lang/cargo/pull/2849)
5841 * [Add support for `RUSTDOCFLAGS`](https://github.com/rust-lang/cargo/pull/2794)
5842
5843 Performance
5844 -----------
5845
5846 * [`panic::catch_unwind` is more optimized](https://github.com/rust-lang/rust/pull/35444)
5847 * [`panic::catch_unwind` no longer accesses thread-local storage on entry](https://github.com/rust-lang/rust/pull/34866)
5848
5849 Tooling
5850 -------
5851
5852 * [Test binaries now support a `--test-threads` argument to specify the number
5853   of threads used to run tests, and which acts the same as the
5854   `RUST_TEST_THREADS` environment variable](https://github.com/rust-lang/rust/pull/35414)
5855 * [The test runner now emits a warning when tests run over 60 seconds](https://github.com/rust-lang/rust/pull/35405)
5856 * [rustdoc: Fix methods in search results](https://github.com/rust-lang/rust/pull/34752)
5857 * [`rust-lldb` warns about unsupported versions of LLDB](https://github.com/rust-lang/rust/pull/34646)
5858 * [Rust releases now come with source packages that can be installed by rustup
5859   via `rustup component add rust-src`](https://github.com/rust-lang/rust/pull/34366).
5860   The resulting source code can be used by tools and IDES, located in the
5861   sysroot under `lib/rustlib/src`.
5862
5863 Misc
5864 ----
5865
5866 * [The compiler can now be built against LLVM 3.9](https://github.com/rust-lang/rust/pull/35594)
5867 * Many minor improvements to the documentation.
5868 * [The Rust exception handling "personality" routine is now written in Rust](https://github.com/rust-lang/rust/pull/34832)
5869
5870 Compatibility Notes
5871 -------------------
5872
5873 * [When printing Windows `OsStr`s, unpaired surrogate codepoints are escaped
5874   with the lowercase format instead of the uppercase](https://github.com/rust-lang/rust/pull/35084)
5875 * [When formatting strings, if "precision" is specified, the "fill",
5876   "align" and "width" specifiers are no longer ignored](https://github.com/rust-lang/rust/pull/34544)
5877 * [The `Debug` impl for strings no longer escapes all non-ASCII characters](https://github.com/rust-lang/rust/pull/34485)
5878
5879
5880 Version 1.11.0 (2016-08-18)
5881 ===========================
5882
5883 Language
5884 --------
5885
5886 * [Support nested `cfg_attr` attributes](https://github.com/rust-lang/rust/pull/34216)
5887 * [Allow statement-generating braced macro invocations at the end of blocks](https://github.com/rust-lang/rust/pull/34436)
5888 * [Macros can be expanded inside of trait definitions](https://github.com/rust-lang/rust/pull/34213)
5889 * [`#[macro_use]` works properly when it is itself expanded from a macro](https://github.com/rust-lang/rust/pull/34032)
5890
5891 Stabilized APIs
5892 ---------------
5893
5894 * [`BinaryHeap::append`](https://doc.rust-lang.org/std/collections/binary_heap/struct.BinaryHeap.html#method.append)
5895 * [`BTreeMap::append`](https://doc.rust-lang.org/std/collections/btree_map/struct.BTreeMap.html#method.append)
5896 * [`BTreeMap::split_off`](https://doc.rust-lang.org/std/collections/btree_map/struct.BTreeMap.html#method.split_off)
5897 * [`BTreeSet::append`](https://doc.rust-lang.org/std/collections/btree_set/struct.BTreeSet.html#method.append)
5898 * [`BTreeSet::split_off`](https://doc.rust-lang.org/std/collections/btree_set/struct.BTreeSet.html#method.split_off)
5899 * [`f32::to_degrees`](https://doc.rust-lang.org/std/primitive.f32.html#method.to_degrees)
5900   (in libcore - previously stabilized in libstd)
5901 * [`f32::to_radians`](https://doc.rust-lang.org/std/primitive.f32.html#method.to_radians)
5902   (in libcore - previously stabilized in libstd)
5903 * [`f64::to_degrees`](https://doc.rust-lang.org/std/primitive.f64.html#method.to_degrees)
5904   (in libcore - previously stabilized in libstd)
5905 * [`f64::to_radians`](https://doc.rust-lang.org/std/primitive.f64.html#method.to_radians)
5906   (in libcore - previously stabilized in libstd)
5907 * [`Iterator::sum`](https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.sum)
5908 * [`Iterator::product`](https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.sum)
5909 * [`Cell::get_mut`](https://doc.rust-lang.org/std/cell/struct.Cell.html#method.get_mut)
5910 * [`RefCell::get_mut`](https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.get_mut)
5911
5912 Libraries
5913 ---------
5914
5915 * [The `thread_local!` macro supports multiple definitions in a single
5916    invocation, and can apply attributes](https://github.com/rust-lang/rust/pull/34077)
5917 * [`Cow` implements `Default`](https://github.com/rust-lang/rust/pull/34305)
5918 * [`Wrapping` implements binary, octal, lower-hex and upper-hex
5919   `Display` formatting](https://github.com/rust-lang/rust/pull/34190)
5920 * [The range types implement `Hash`](https://github.com/rust-lang/rust/pull/34180)
5921 * [`lookup_host` ignores unknown address types](https://github.com/rust-lang/rust/pull/34067)
5922 * [`assert_eq!` accepts a custom error message, like `assert!` does](https://github.com/rust-lang/rust/pull/33976)
5923 * [The main thread is now called "main" instead of "&lt;main&gt;"](https://github.com/rust-lang/rust/pull/33803)
5924
5925 Cargo
5926 -----
5927
5928 * [Disallow specifying features of transitive deps](https://github.com/rust-lang/cargo/pull/2821)
5929 * [Add color support for Windows consoles](https://github.com/rust-lang/cargo/pull/2804)
5930 * [Fix `harness = false` on `[lib]` sections](https://github.com/rust-lang/cargo/pull/2795)
5931 * [Don't panic when `links` contains a '.'](https://github.com/rust-lang/cargo/pull/2787)
5932 * [Build scripts can emit warnings](https://github.com/rust-lang/cargo/pull/2630),
5933   and `-vv` prints warnings for all crates.
5934 * [Ignore file locks on OS X NFS mounts](https://github.com/rust-lang/cargo/pull/2720)
5935 * [Don't warn about `package.metadata` keys](https://github.com/rust-lang/cargo/pull/2668).
5936   This provides room for expansion by arbitrary tools.
5937 * [Add support for cdylib crate types](https://github.com/rust-lang/cargo/pull/2741)
5938 * [Prevent publishing crates when files are dirty](https://github.com/rust-lang/cargo/pull/2781)
5939 * [Don't fetch all crates on clean](https://github.com/rust-lang/cargo/pull/2704)
5940 * [Propagate --color option to rustc](https://github.com/rust-lang/cargo/pull/2779)
5941 * [Fix `cargo doc --open` on Windows](https://github.com/rust-lang/cargo/pull/2780)
5942 * [Improve autocompletion](https://github.com/rust-lang/cargo/pull/2772)
5943 * [Configure colors of stderr as well as stdout](https://github.com/rust-lang/cargo/pull/2739)
5944
5945 Performance
5946 -----------
5947
5948 * [Caching projections speeds up type check dramatically for some
5949   workloads](https://github.com/rust-lang/rust/pull/33816)
5950 * [The default `HashMap` hasher is SipHash 1-3 instead of SipHash 2-4](https://github.com/rust-lang/rust/pull/33940)
5951   This hasher is faster, but is believed to provide sufficient
5952   protection from collision attacks.
5953 * [Comparison of `Ipv4Addr` is 10x faster](https://github.com/rust-lang/rust/pull/33891)
5954
5955 Rustdoc
5956 -------
5957
5958 * [Fix empty implementation section on some module pages](https://github.com/rust-lang/rust/pull/34536)
5959 * [Fix inlined renamed re-exports in import lists](https://github.com/rust-lang/rust/pull/34479)
5960 * [Fix search result layout for enum variants and struct fields](https://github.com/rust-lang/rust/pull/34477)
5961 * [Fix issues with source links to external crates](https://github.com/rust-lang/rust/pull/34387)
5962 * [Fix redirect pages for renamed re-exports](https://github.com/rust-lang/rust/pull/34245)
5963
5964 Tooling
5965 -------
5966
5967 * [rustc is better at finding the MSVC toolchain](https://github.com/rust-lang/rust/pull/34492)
5968 * [When emitting debug info, rustc emits frame pointers for closures,
5969   shims and glue, as it does for all other functions](https://github.com/rust-lang/rust/pull/33909)
5970 * [rust-lldb warns about unsupported versions of LLDB](https://github.com/rust-lang/rust/pull/34646)
5971 * Many more errors have been given error codes and extended
5972   explanations
5973 * API documentation continues to be improved, with many new examples
5974
5975 Misc
5976 ----
5977
5978 * [rustc no longer hangs when dependencies recursively re-export
5979   submodules](https://github.com/rust-lang/rust/pull/34542)
5980 * [rustc requires LLVM 3.7+](https://github.com/rust-lang/rust/pull/34104)
5981 * [The 'How Safe and Unsafe Interact' chapter of The Rustonomicon was
5982   rewritten](https://github.com/rust-lang/rust/pull/33895)
5983 * [rustc support 16-bit pointer sizes](https://github.com/rust-lang/rust/pull/33460).
5984   No targets use this yet, but it works toward AVR support.
5985
5986 Compatibility Notes
5987 -------------------
5988
5989 * [`const`s and `static`s may not have unsized types](https://github.com/rust-lang/rust/pull/34443)
5990 * [The new follow-set rules that place restrictions on `macro_rules!`
5991   in order to ensure syntax forward-compatibility have been enabled](https://github.com/rust-lang/rust/pull/33982)
5992   This was an [amendment to RFC 550](https://github.com/rust-lang/rfcs/pull/1384),
5993   and has been a warning since 1.10.
5994 * [`cfg` attribute process has been refactored to fix various bugs](https://github.com/rust-lang/rust/pull/33706).
5995   This causes breakage in some corner cases.
5996
5997
5998 Version 1.10.0 (2016-07-07)
5999 ===========================
6000
6001 Language
6002 --------
6003
6004 * [`Copy` types are required to have a trivial implementation of `Clone`](https://github.com/rust-lang/rust/pull/33420).
6005   [RFC 1521](https://github.com/rust-lang/rfcs/blob/master/text/1521-copy-clone-semantics.md).
6006 * [Single-variant enums support the `#[repr(..)]` attribute](https://github.com/rust-lang/rust/pull/33355).
6007 * [Fix `#[derive(RustcEncodable)]` in the presence of other `encode` methods](https://github.com/rust-lang/rust/pull/32908).
6008 * [`panic!` can be converted to a runtime abort with the
6009   `-C panic=abort` flag](https://github.com/rust-lang/rust/pull/32900).
6010   [RFC 1513](https://github.com/rust-lang/rfcs/blob/master/text/1513-less-unwinding.md).
6011 * [Add a new crate type, 'cdylib'](https://github.com/rust-lang/rust/pull/33553).
6012   cdylibs are dynamic libraries suitable for loading by non-Rust hosts.
6013   [RFC 1510](https://github.com/rust-lang/rfcs/blob/master/text/1510-cdylib.md).
6014   Note that Cargo does not yet directly support cdylibs.
6015
6016 Stabilized APIs
6017 ---------------
6018
6019 * `os::windows::fs::OpenOptionsExt::access_mode`
6020 * `os::windows::fs::OpenOptionsExt::share_mode`
6021 * `os::windows::fs::OpenOptionsExt::custom_flags`
6022 * `os::windows::fs::OpenOptionsExt::attributes`
6023 * `os::windows::fs::OpenOptionsExt::security_qos_flags`
6024 * `os::unix::fs::OpenOptionsExt::custom_flags`
6025 * [`sync::Weak::new`](http://doc.rust-lang.org/alloc/arc/struct.Weak.html#method.new)
6026 * `Default for sync::Weak`
6027 * [`panic::set_hook`](http://doc.rust-lang.org/std/panic/fn.set_hook.html)
6028 * [`panic::take_hook`](http://doc.rust-lang.org/std/panic/fn.take_hook.html)
6029 * [`panic::PanicInfo`](http://doc.rust-lang.org/std/panic/struct.PanicInfo.html)
6030 * [`panic::PanicInfo::payload`](http://doc.rust-lang.org/std/panic/struct.PanicInfo.html#method.payload)
6031 * [`panic::PanicInfo::location`](http://doc.rust-lang.org/std/panic/struct.PanicInfo.html#method.location)
6032 * [`panic::Location`](http://doc.rust-lang.org/std/panic/struct.Location.html)
6033 * [`panic::Location::file`](http://doc.rust-lang.org/std/panic/struct.Location.html#method.file)
6034 * [`panic::Location::line`](http://doc.rust-lang.org/std/panic/struct.Location.html#method.line)
6035 * [`ffi::CStr::from_bytes_with_nul`](http://doc.rust-lang.org/std/ffi/struct.CStr.html#method.from_bytes_with_nul)
6036 * [`ffi::CStr::from_bytes_with_nul_unchecked`](http://doc.rust-lang.org/std/ffi/struct.CStr.html#method.from_bytes_with_nul_unchecked)
6037 * [`ffi::FromBytesWithNulError`](http://doc.rust-lang.org/std/ffi/struct.FromBytesWithNulError.html)
6038 * [`fs::Metadata::modified`](http://doc.rust-lang.org/std/fs/struct.Metadata.html#method.modified)
6039 * [`fs::Metadata::accessed`](http://doc.rust-lang.org/std/fs/struct.Metadata.html#method.accessed)
6040 * [`fs::Metadata::created`](http://doc.rust-lang.org/std/fs/struct.Metadata.html#method.created)
6041 * `sync::atomic::Atomic{Usize,Isize,Bool,Ptr}::compare_exchange`
6042 * `sync::atomic::Atomic{Usize,Isize,Bool,Ptr}::compare_exchange_weak`
6043 * `collections::{btree,hash}_map::{Occupied,Vacant,}Entry::key`
6044 * `os::unix::net::{UnixStream, UnixListener, UnixDatagram, SocketAddr}`
6045 * [`SocketAddr::is_unnamed`](http://doc.rust-lang.org/std/os/unix/net/struct.SocketAddr.html#method.is_unnamed)
6046 * [`SocketAddr::as_pathname`](http://doc.rust-lang.org/std/os/unix/net/struct.SocketAddr.html#method.as_pathname)
6047 * [`UnixStream::connect`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.connect)
6048 * [`UnixStream::pair`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.pair)
6049 * [`UnixStream::try_clone`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.try_clone)
6050 * [`UnixStream::local_addr`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.local_addr)
6051 * [`UnixStream::peer_addr`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.peer_addr)
6052 * [`UnixStream::set_read_timeout`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.read_timeout)
6053 * [`UnixStream::set_write_timeout`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.write_timeout)
6054 * [`UnixStream::read_timeout`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.read_timeout)
6055 * [`UnixStream::write_timeout`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.write_timeout)
6056 * [`UnixStream::set_nonblocking`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.set_nonblocking)
6057 * [`UnixStream::take_error`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.take_error)
6058 * [`UnixStream::shutdown`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html#method.shutdown)
6059 * Read/Write/RawFd impls for `UnixStream`
6060 * [`UnixListener::bind`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixListener.html#method.bind)
6061 * [`UnixListener::accept`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixListener.html#method.accept)
6062 * [`UnixListener::try_clone`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixListener.html#method.try_clone)
6063 * [`UnixListener::local_addr`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixListener.html#method.local_addr)
6064 * [`UnixListener::set_nonblocking`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixListener.html#method.set_nonblocking)
6065 * [`UnixListener::take_error`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixListener.html#method.take_error)
6066 * [`UnixListener::incoming`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixListener.html#method.incoming)
6067 * RawFd impls for `UnixListener`
6068 * [`UnixDatagram::bind`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.bind)
6069 * [`UnixDatagram::unbound`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.unbound)
6070 * [`UnixDatagram::pair`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.pair)
6071 * [`UnixDatagram::connect`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.connect)
6072 * [`UnixDatagram::try_clone`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.try_clone)
6073 * [`UnixDatagram::local_addr`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.local_addr)
6074 * [`UnixDatagram::peer_addr`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.peer_addr)
6075 * [`UnixDatagram::recv_from`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.recv_from)
6076 * [`UnixDatagram::recv`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.recv)
6077 * [`UnixDatagram::send_to`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.send_to)
6078 * [`UnixDatagram::send`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.send)
6079 * [`UnixDatagram::set_read_timeout`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.set_read_timeout)
6080 * [`UnixDatagram::set_write_timeout`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.set_write_timeout)
6081 * [`UnixDatagram::read_timeout`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.read_timeout)
6082 * [`UnixDatagram::write_timeout`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.write_timeout)
6083 * [`UnixDatagram::set_nonblocking`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.set_nonblocking)
6084 * [`UnixDatagram::take_error`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.take_error)
6085 * [`UnixDatagram::shutdown`](http://doc.rust-lang.org/std/os/unix/net/struct.UnixDatagram.html#method.shutdown)
6086 * RawFd impls for `UnixDatagram`
6087 * `{BTree,Hash}Map::values_mut`
6088 * [`<[_]>::binary_search_by_key`](http://doc.rust-lang.org/std/primitive.slice.html#method.binary_search_by_key)
6089
6090 Libraries
6091 ---------
6092
6093 * [The `abs_sub` method of floats is deprecated](https://github.com/rust-lang/rust/pull/33664).
6094   The semantics of this minor method are subtle and probably not what
6095   most people want.
6096 * [Add implementation of Ord for Cell<T> and RefCell<T> where T: Ord](https://github.com/rust-lang/rust/pull/33306).
6097 * [On Linux, if `HashMap`s can't be initialized with `getrandom` they
6098   will fall back to `/dev/urandom` temporarily to avoid blocking
6099   during early boot](https://github.com/rust-lang/rust/pull/33086).
6100 * [Implemented negation for wrapping numerals](https://github.com/rust-lang/rust/pull/33067).
6101 * [Implement `Clone` for `binary_heap::IntoIter`](https://github.com/rust-lang/rust/pull/33050).
6102 * [Implement `Display` and `Hash` for `std::num::Wrapping`](https://github.com/rust-lang/rust/pull/33023).
6103 * [Add `Default` implementation for `&CStr`, `CString`](https://github.com/rust-lang/rust/pull/32990).
6104 * [Implement `From<Vec<T>>` and `Into<Vec<T>>` for `VecDeque<T>`](https://github.com/rust-lang/rust/pull/32866).
6105 * [Implement `Default` for `UnsafeCell`, `fmt::Error`, `Condvar`,
6106   `Mutex`, `RwLock`](https://github.com/rust-lang/rust/pull/32785).
6107
6108 Cargo
6109 -----
6110 * [Cargo.toml supports the `profile.*.panic` option](https://github.com/rust-lang/cargo/pull/2687).
6111   This controls the runtime behavior of the `panic!` macro
6112   and can be either "unwind" (the default), or "abort".
6113   [RFC 1513](https://github.com/rust-lang/rfcs/blob/master/text/1513-less-unwinding.md).
6114 * [Don't throw away errors with `-p` arguments](https://github.com/rust-lang/cargo/pull/2723).
6115 * [Report status to stderr instead of stdout](https://github.com/rust-lang/cargo/pull/2693).
6116 * [Build scripts are passed a `CARGO_MANIFEST_LINKS` environment
6117   variable that corresponds to the `links` field of the manifest](https://github.com/rust-lang/cargo/pull/2710).
6118 * [Ban keywords from crate names](https://github.com/rust-lang/cargo/pull/2707).
6119 * [Canonicalize `CARGO_HOME` on Windows](https://github.com/rust-lang/cargo/pull/2604).
6120 * [Retry network requests](https://github.com/rust-lang/cargo/pull/2396).
6121   By default they are retried twice, which can be customized with the
6122   `net.retry` value in `.cargo/config`.
6123 * [Don't print extra error info for failing subcommands](https://github.com/rust-lang/cargo/pull/2674).
6124 * [Add `--force` flag to `cargo install`](https://github.com/rust-lang/cargo/pull/2405).
6125 * [Don't use `flock` on NFS mounts](https://github.com/rust-lang/cargo/pull/2623).
6126 * [Prefer building `cargo install` artifacts in temporary directories](https://github.com/rust-lang/cargo/pull/2610).
6127   Makes it possible to install multiple crates in parallel.
6128 * [Add `cargo test --doc`](https://github.com/rust-lang/cargo/pull/2578).
6129 * [Add `cargo --explain`](https://github.com/rust-lang/cargo/pull/2551).
6130 * [Don't print warnings when `-q` is passed](https://github.com/rust-lang/cargo/pull/2576).
6131 * [Add `cargo doc --lib` and `--bin`](https://github.com/rust-lang/cargo/pull/2577).
6132 * [Don't require build script output to be UTF-8](https://github.com/rust-lang/cargo/pull/2560).
6133 * [Correctly attempt multiple git usernames](https://github.com/rust-lang/cargo/pull/2584).
6134
6135 Performance
6136 -----------
6137
6138 * [rustc memory usage was reduced by refactoring the context used for
6139   type checking](https://github.com/rust-lang/rust/pull/33425).
6140 * [Speed up creation of `HashMap`s by caching the random keys used
6141   to initialize the hash state](https://github.com/rust-lang/rust/pull/33318).
6142 * [The `find` implementation for `Chain` iterators is 2x faster](https://github.com/rust-lang/rust/pull/33289).
6143 * [Trait selection optimizations speed up type checking by 15%](https://github.com/rust-lang/rust/pull/33138).
6144 * [Efficient trie lookup for boolean Unicode properties](https://github.com/rust-lang/rust/pull/33098).
6145   10x faster than the previous lookup tables.
6146 * [Special case `#[derive(Copy, Clone)]` to avoid bloat](https://github.com/rust-lang/rust/pull/31414).
6147
6148 Usability
6149 ---------
6150
6151 * Many incremental improvements to documentation and rustdoc.
6152 * [rustdoc: List blanket trait impls](https://github.com/rust-lang/rust/pull/33514).
6153 * [rustdoc: Clean up ABI rendering](https://github.com/rust-lang/rust/pull/33151).
6154 * [Indexing with the wrong type produces a more informative error](https://github.com/rust-lang/rust/pull/33401).
6155 * [Improve diagnostics for constants being used in irrefutable patterns](https://github.com/rust-lang/rust/pull/33406).
6156 * [When many method candidates are in scope limit the suggestions to 10](https://github.com/rust-lang/rust/pull/33338).
6157 * [Remove confusing suggestion when calling a `fn` type](https://github.com/rust-lang/rust/pull/33325).
6158 * [Do not suggest changing `&mut self` to `&mut mut self`](https://github.com/rust-lang/rust/pull/33319).
6159
6160 Misc
6161 ----
6162
6163 * [Update i686-linux-android features to match Android ABI](https://github.com/rust-lang/rust/pull/33651).
6164 * [Update aarch64-linux-android features to match Android ABI](https://github.com/rust-lang/rust/pull/33500).
6165 * [`std` no longer prints backtraces on platforms where the running
6166   module must be loaded with `env::current_exe`, which can't be relied
6167   on](https://github.com/rust-lang/rust/pull/33554).
6168 * This release includes std binaries for the i586-unknown-linux-gnu,
6169   i686-unknown-linux-musl, and armv7-linux-androideabi targets. The
6170   i586 target is for old x86 hardware without SSE2, and the armv7
6171   target is for Android running on modern ARM architectures.
6172 * [The `rust-gdb` and `rust-lldb` scripts are distributed on all
6173   Unix platforms](https://github.com/rust-lang/rust/pull/32835).
6174 * [On Unix the runtime aborts by calling `libc::abort` instead of
6175   generating an illegal instruction](https://github.com/rust-lang/rust/pull/31457).
6176 * [Rust is now bootstrapped from the previous release of Rust,
6177   instead of a snapshot from an arbitrary commit](https://github.com/rust-lang/rust/pull/32942).
6178
6179 Compatibility Notes
6180 -------------------
6181
6182 * [`AtomicBool` is now bool-sized, not word-sized](https://github.com/rust-lang/rust/pull/33579).
6183 * [`target_env` for Linux ARM targets is just `gnu`, not
6184   `gnueabihf`, `gnueabi`, etc](https://github.com/rust-lang/rust/pull/33403).
6185 * [Consistently panic on overflow in `Duration::new`](https://github.com/rust-lang/rust/pull/33072).
6186 * [Change `String::truncate` to panic less](https://github.com/rust-lang/rust/pull/32977).
6187 * [Add `:block` to the follow set for `:ty` and `:path`](https://github.com/rust-lang/rust/pull/32945).
6188   Affects how macros are parsed.
6189 * [Fix macro hygiene bug](https://github.com/rust-lang/rust/pull/32923).
6190 * [Feature-gated attributes on macro-generated macro invocations are
6191   now rejected](https://github.com/rust-lang/rust/pull/32791).
6192 * [Suppress fallback and ambiguity errors during type inference](https://github.com/rust-lang/rust/pull/32258).
6193   This caused some minor changes to type inference.
6194
6195
6196 Version 1.9.0 (2016-05-26)
6197 ==========================
6198
6199 Language
6200 --------
6201
6202 * The `#[deprecated]` attribute when applied to an API will generate
6203   warnings when used. The warnings may be suppressed with
6204   `#[allow(deprecated)]`. [RFC 1270].
6205 * [`fn` item types are zero sized, and each `fn` names a unique
6206   type][1.9fn]. This will break code that transmutes `fn`s, so calling
6207   `transmute` on a `fn` type will generate a warning for a few cycles,
6208   then will be converted to an error.
6209 * [Field and method resolution understand visibility, so private
6210   fields and methods cannot prevent the proper use of public fields
6211   and methods][1.9fv].
6212 * [The parser considers unicode codepoints in the
6213   `PATTERN_WHITE_SPACE` category to be whitespace][1.9ws].
6214
6215 Stabilized APIs
6216 ---------------
6217
6218 * [`std::panic`]
6219 * [`std::panic::catch_unwind`] (renamed from `recover`)
6220 * [`std::panic::resume_unwind`] (renamed from `propagate`)
6221 * [`std::panic::AssertUnwindSafe`] (renamed from `AssertRecoverSafe`)
6222 * [`std::panic::UnwindSafe`] (renamed from `RecoverSafe`)
6223 * [`str::is_char_boundary`]
6224 * [`<*const T>::as_ref`]
6225 * [`<*mut T>::as_ref`]
6226 * [`<*mut T>::as_mut`]
6227 * [`AsciiExt::make_ascii_uppercase`]
6228 * [`AsciiExt::make_ascii_lowercase`]
6229 * [`char::decode_utf16`]
6230 * [`char::DecodeUtf16`]
6231 * [`char::DecodeUtf16Error`]
6232 * [`char::DecodeUtf16Error::unpaired_surrogate`]
6233 * [`BTreeSet::take`]
6234 * [`BTreeSet::replace`]
6235 * [`BTreeSet::get`]
6236 * [`HashSet::take`]
6237 * [`HashSet::replace`]
6238 * [`HashSet::get`]
6239 * [`OsString::with_capacity`]
6240 * [`OsString::clear`]
6241 * [`OsString::capacity`]
6242 * [`OsString::reserve`]
6243 * [`OsString::reserve_exact`]
6244 * [`OsStr::is_empty`]
6245 * [`OsStr::len`]
6246 * [`std::os::unix::thread`]
6247 * [`RawPthread`]
6248 * [`JoinHandleExt`]
6249 * [`JoinHandleExt::as_pthread_t`]
6250 * [`JoinHandleExt::into_pthread_t`]
6251 * [`HashSet::hasher`]
6252 * [`HashMap::hasher`]
6253 * [`CommandExt::exec`]
6254 * [`File::try_clone`]
6255 * [`SocketAddr::set_ip`]
6256 * [`SocketAddr::set_port`]
6257 * [`SocketAddrV4::set_ip`]
6258 * [`SocketAddrV4::set_port`]
6259 * [`SocketAddrV6::set_ip`]
6260 * [`SocketAddrV6::set_port`]
6261 * [`SocketAddrV6::set_flowinfo`]
6262 * [`SocketAddrV6::set_scope_id`]
6263 * [`slice::copy_from_slice`]
6264 * [`ptr::read_volatile`]
6265 * [`ptr::write_volatile`]
6266 * [`OpenOptions::create_new`]
6267 * [`TcpStream::set_nodelay`]
6268 * [`TcpStream::nodelay`]
6269 * [`TcpStream::set_ttl`]
6270 * [`TcpStream::ttl`]
6271 * [`TcpStream::set_only_v6`]
6272 * [`TcpStream::only_v6`]
6273 * [`TcpStream::take_error`]
6274 * [`TcpStream::set_nonblocking`]
6275 * [`TcpListener::set_ttl`]
6276 * [`TcpListener::ttl`]
6277 * [`TcpListener::set_only_v6`]
6278 * [`TcpListener::only_v6`]
6279 * [`TcpListener::take_error`]
6280 * [`TcpListener::set_nonblocking`]
6281 * [`UdpSocket::set_broadcast`]
6282 * [`UdpSocket::broadcast`]
6283 * [`UdpSocket::set_multicast_loop_v4`]
6284 * [`UdpSocket::multicast_loop_v4`]
6285 * [`UdpSocket::set_multicast_ttl_v4`]
6286 * [`UdpSocket::multicast_ttl_v4`]
6287 * [`UdpSocket::set_multicast_loop_v6`]
6288 * [`UdpSocket::multicast_loop_v6`]
6289 * [`UdpSocket::set_multicast_ttl_v6`]
6290 * [`UdpSocket::multicast_ttl_v6`]
6291 * [`UdpSocket::set_ttl`]
6292 * [`UdpSocket::ttl`]
6293 * [`UdpSocket::set_only_v6`]
6294 * [`UdpSocket::only_v6`]
6295 * [`UdpSocket::join_multicast_v4`]
6296 * [`UdpSocket::join_multicast_v6`]
6297 * [`UdpSocket::leave_multicast_v4`]
6298 * [`UdpSocket::leave_multicast_v6`]
6299 * [`UdpSocket::take_error`]
6300 * [`UdpSocket::connect`]
6301 * [`UdpSocket::send`]
6302 * [`UdpSocket::recv`]
6303 * [`UdpSocket::set_nonblocking`]
6304
6305 Libraries
6306 ---------
6307
6308 * [`std::sync::Once` is poisoned if its initialization function
6309   fails][1.9o].
6310 * [`cell::Ref` and `cell::RefMut` can contain unsized types][1.9cu].
6311 * [Most types implement `fmt::Debug`][1.9db].
6312 * [The default buffer size used by `BufReader` and `BufWriter` was
6313   reduced to 8K, from 64K][1.9bf]. This is in line with the buffer size
6314   used by other languages.
6315 * [`Instant`, `SystemTime` and `Duration` implement `+=` and `-=`.
6316   `Duration` additionally implements `*=` and `/=`][1.9ta].
6317 * [`Skip` is a `DoubleEndedIterator`][1.9sk].
6318 * [`From<[u8; 4]>` is implemented for `Ipv4Addr`][1.9fi].
6319 * [`Chain` implements `BufRead`][1.9ch].
6320 * [`HashMap`, `HashSet` and iterators are covariant][1.9hc].
6321
6322 Cargo
6323 -----
6324
6325 * [Cargo can now run concurrently][1.9cc].
6326 * [Top-level overrides allow specific revisions of crates to be
6327   overridden through the entire crate graph][1.9ct].  This is intended
6328   to make upgrades easier for large projects, by allowing crates to be
6329   forked temporarily until they've been upgraded and republished.
6330 * [Cargo exports a `CARGO_PKG_AUTHORS` environment variable][1.9cp].
6331 * [Cargo will pass the contents of the `RUSTFLAGS` variable to `rustc`
6332   on the commandline][1.9cf]. `rustc` arguments can also be specified
6333   in the `build.rustflags` configuration key.
6334
6335 Performance
6336 -----------
6337
6338 * [The time complexity of comparing variables for equivalence during type
6339   unification is reduced from _O_(_n_!) to _O_(_n_)][1.9tu]. This leads
6340   to major compilation time improvement in some scenarios.
6341 * [`ToString` is specialized for `str`, giving it the same performance
6342   as `to_owned`][1.9ts].
6343 * [Spawning processes with `Command::output` no longer creates extra
6344   threads][1.9sp].
6345 * [`#[derive(PartialEq)]` and `#[derive(PartialOrd)]` emit less code
6346   for C-like enums][1.9cl].
6347
6348 Misc
6349 ----
6350
6351 * [Passing the `--quiet` flag to a test runner will produce
6352   much-abbreviated output][1.9q].
6353 * The Rust Project now publishes std binaries for the
6354   `mips-unknown-linux-musl`, `mipsel-unknown-linux-musl`, and
6355   `i586-pc-windows-msvc` targets.
6356
6357 Compatibility Notes
6358 -------------------
6359
6360 * [`std::sync::Once` is poisoned if its initialization function
6361   fails][1.9o].
6362 * [It is illegal to define methods with the same name in overlapping
6363   inherent `impl` blocks][1.9sn].
6364 * [`fn` item types are zero sized, and each `fn` names a unique
6365   type][1.9fn]. This will break code that transmutes `fn`s, so calling
6366   `transmute` on a `fn` type will generate a warning for a few cycles,
6367   then will be converted to an error.
6368 * [Improvements to const evaluation may trigger new errors when integer
6369   literals are out of range][1.9ce].
6370
6371
6372 [1.9bf]: https://github.com/rust-lang/rust/pull/32695
6373 [1.9cc]: https://github.com/rust-lang/cargo/pull/2486
6374 [1.9ce]: https://github.com/rust-lang/rust/pull/30587
6375 [1.9cf]: https://github.com/rust-lang/cargo/pull/2241
6376 [1.9ch]: https://github.com/rust-lang/rust/pull/32541
6377 [1.9cl]: https://github.com/rust-lang/rust/pull/31977
6378 [1.9cp]: https://github.com/rust-lang/cargo/pull/2465
6379 [1.9ct]: https://github.com/rust-lang/cargo/pull/2385
6380 [1.9cu]: https://github.com/rust-lang/rust/pull/32652
6381 [1.9db]: https://github.com/rust-lang/rust/pull/32054
6382 [1.9fi]: https://github.com/rust-lang/rust/pull/32050
6383 [1.9fn]: https://github.com/rust-lang/rust/pull/31710
6384 [1.9fv]: https://github.com/rust-lang/rust/pull/31938
6385 [1.9hc]: https://github.com/rust-lang/rust/pull/32635
6386 [1.9o]: https://github.com/rust-lang/rust/pull/32325
6387 [1.9q]: https://github.com/rust-lang/rust/pull/31887
6388 [1.9sk]: https://github.com/rust-lang/rust/pull/31700
6389 [1.9sn]: https://github.com/rust-lang/rust/pull/31925
6390 [1.9sp]: https://github.com/rust-lang/rust/pull/31618
6391 [1.9ta]: https://github.com/rust-lang/rust/pull/32448
6392 [1.9ts]: https://github.com/rust-lang/rust/pull/32586
6393 [1.9tu]: https://github.com/rust-lang/rust/pull/32062
6394 [1.9ws]: https://github.com/rust-lang/rust/pull/29734
6395 [RFC 1270]: https://github.com/rust-lang/rfcs/blob/master/text/1270-deprecation.md
6396 [`<*const T>::as_ref`]: http://doc.rust-lang.org/nightly/std/primitive.pointer.html#method.as_ref
6397 [`<*mut T>::as_mut`]: http://doc.rust-lang.org/nightly/std/primitive.pointer.html#method.as_mut
6398 [`<*mut T>::as_ref`]: http://doc.rust-lang.org/nightly/std/primitive.pointer.html#method.as_ref
6399 [`slice::copy_from_slice`]: http://doc.rust-lang.org/nightly/std/primitive.slice.html#method.copy_from_slice
6400 [`AsciiExt::make_ascii_lowercase`]: http://doc.rust-lang.org/nightly/std/ascii/trait.AsciiExt.html#tymethod.make_ascii_lowercase
6401 [`AsciiExt::make_ascii_uppercase`]: http://doc.rust-lang.org/nightly/std/ascii/trait.AsciiExt.html#tymethod.make_ascii_uppercase
6402 [`BTreeSet::get`]: http://doc.rust-lang.org/nightly/collections/btree/set/struct.BTreeSet.html#method.get
6403 [`BTreeSet::replace`]: http://doc.rust-lang.org/nightly/collections/btree/set/struct.BTreeSet.html#method.replace
6404 [`BTreeSet::take`]: http://doc.rust-lang.org/nightly/collections/btree/set/struct.BTreeSet.html#method.take
6405 [`CommandExt::exec`]: http://doc.rust-lang.org/nightly/std/os/unix/process/trait.CommandExt.html#tymethod.exec
6406 [`File::try_clone`]: http://doc.rust-lang.org/nightly/std/fs/struct.File.html#method.try_clone
6407 [`HashMap::hasher`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashMap.html#method.hasher
6408 [`HashSet::get`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashSet.html#method.get
6409 [`HashSet::hasher`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashSet.html#method.hasher
6410 [`HashSet::replace`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashSet.html#method.replace
6411 [`HashSet::take`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashSet.html#method.take
6412 [`JoinHandleExt::as_pthread_t`]: http://doc.rust-lang.org/nightly/std/os/unix/thread/trait.JoinHandleExt.html#tymethod.as_pthread_t
6413 [`JoinHandleExt::into_pthread_t`]: http://doc.rust-lang.org/nightly/std/os/unix/thread/trait.JoinHandleExt.html#tymethod.into_pthread_t
6414 [`JoinHandleExt`]: http://doc.rust-lang.org/nightly/std/os/unix/thread/trait.JoinHandleExt.html
6415 [`OpenOptions::create_new`]: http://doc.rust-lang.org/nightly/std/fs/struct.OpenOptions.html#method.create_new
6416 [`OsStr::is_empty`]: http://doc.rust-lang.org/nightly/std/ffi/struct.OsStr.html#method.is_empty
6417 [`OsStr::len`]: http://doc.rust-lang.org/nightly/std/ffi/struct.OsStr.html#method.len
6418 [`OsString::capacity`]: http://doc.rust-lang.org/nightly/std/ffi/struct.OsString.html#method.capacity
6419 [`OsString::clear`]: http://doc.rust-lang.org/nightly/std/ffi/struct.OsString.html#method.clear
6420 [`OsString::reserve_exact`]: http://doc.rust-lang.org/nightly/std/ffi/struct.OsString.html#method.reserve_exact
6421 [`OsString::reserve`]: http://doc.rust-lang.org/nightly/std/ffi/struct.OsString.html#method.reserve
6422 [`OsString::with_capacity`]: http://doc.rust-lang.org/nightly/std/ffi/struct.OsString.html#method.with_capacity
6423 [`RawPthread`]: http://doc.rust-lang.org/nightly/std/os/unix/thread/type.RawPthread.html
6424 [`SocketAddr::set_ip`]: http://doc.rust-lang.org/nightly/std/net/enum.SocketAddr.html#method.set_ip
6425 [`SocketAddr::set_port`]: http://doc.rust-lang.org/nightly/std/net/enum.SocketAddr.html#method.set_port
6426 [`SocketAddrV4::set_ip`]: http://doc.rust-lang.org/nightly/std/net/struct.SocketAddrV4.html#method.set_ip
6427 [`SocketAddrV4::set_port`]: http://doc.rust-lang.org/nightly/std/net/struct.SocketAddrV4.html#method.set_port
6428 [`SocketAddrV6::set_flowinfo`]: http://doc.rust-lang.org/nightly/std/net/struct.SocketAddrV6.html#method.set_flowinfo
6429 [`SocketAddrV6::set_ip`]: http://doc.rust-lang.org/nightly/std/net/struct.SocketAddrV6.html#method.set_ip
6430 [`SocketAddrV6::set_port`]: http://doc.rust-lang.org/nightly/std/net/struct.SocketAddrV6.html#method.set_port
6431 [`SocketAddrV6::set_scope_id`]: http://doc.rust-lang.org/nightly/std/net/struct.SocketAddrV6.html#method.set_scope_id
6432 [`TcpListener::only_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.only_v6
6433 [`TcpListener::set_nonblocking`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_nonblocking
6434 [`TcpListener::set_only_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_only_v6
6435 [`TcpListener::set_ttl`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_ttl
6436 [`TcpListener::take_error`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.take_error
6437 [`TcpListener::ttl`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.ttl
6438 [`TcpStream::nodelay`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.nodelay
6439 [`TcpStream::only_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.only_v6
6440 [`TcpStream::set_nodelay`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_nodelay
6441 [`TcpStream::set_nonblocking`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_nonblocking
6442 [`TcpStream::set_only_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_only_v6
6443 [`TcpStream::set_ttl`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_ttl
6444 [`TcpStream::take_error`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.take_error
6445 [`TcpStream::ttl`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.ttl
6446 [`UdpSocket::broadcast`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.broadcast
6447 [`UdpSocket::connect`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.connect
6448 [`UdpSocket::join_multicast_v4`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.join_multicast_v4
6449 [`UdpSocket::join_multicast_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.join_multicast_v6
6450 [`UdpSocket::leave_multicast_v4`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.leave_multicast_v4
6451 [`UdpSocket::leave_multicast_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.leave_multicast_v6
6452 [`UdpSocket::multicast_loop_v4`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.multicast_loop_v4
6453 [`UdpSocket::multicast_loop_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.multicast_loop_v6
6454 [`UdpSocket::multicast_ttl_v4`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.multicast_ttl_v4
6455 [`UdpSocket::multicast_ttl_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.multicast_ttl_v6
6456 [`UdpSocket::only_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.only_v6
6457 [`UdpSocket::recv`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.recv
6458 [`UdpSocket::send`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.send
6459 [`UdpSocket::set_broadcast`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.set_broadcast
6460 [`UdpSocket::set_multicast_loop_v4`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.set_multicast_loop_v4
6461 [`UdpSocket::set_multicast_loop_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.set_multicast_loop_v6
6462 [`UdpSocket::set_multicast_ttl_v4`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.set_multicast_ttl_v4
6463 [`UdpSocket::set_multicast_ttl_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.set_multicast_ttl_v6
6464 [`UdpSocket::set_nonblocking`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.set_nonblocking
6465 [`UdpSocket::set_only_v6`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.set_only_v6
6466 [`UdpSocket::set_ttl`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.set_ttl
6467 [`UdpSocket::take_error`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.take_error
6468 [`UdpSocket::ttl`]: http://doc.rust-lang.org/nightly/std/net/struct.UdpSocket.html#method.ttl
6469 [`char::DecodeUtf16Error::unpaired_surrogate`]: http://doc.rust-lang.org/nightly/std/char/struct.DecodeUtf16Error.html#method.unpaired_surrogate
6470 [`char::DecodeUtf16Error`]: http://doc.rust-lang.org/nightly/std/char/struct.DecodeUtf16Error.html
6471 [`char::DecodeUtf16`]: http://doc.rust-lang.org/nightly/std/char/struct.DecodeUtf16.html
6472 [`char::decode_utf16`]: http://doc.rust-lang.org/nightly/std/char/fn.decode_utf16.html
6473 [`ptr::read_volatile`]: http://doc.rust-lang.org/nightly/std/ptr/fn.read_volatile.html
6474 [`ptr::write_volatile`]: http://doc.rust-lang.org/nightly/std/ptr/fn.write_volatile.html
6475 [`std::os::unix::thread`]: http://doc.rust-lang.org/nightly/std/os/unix/thread/index.html
6476 [`std::panic::AssertUnwindSafe`]: http://doc.rust-lang.org/nightly/std/panic/struct.AssertUnwindSafe.html
6477 [`std::panic::UnwindSafe`]: http://doc.rust-lang.org/nightly/std/panic/trait.UnwindSafe.html
6478 [`std::panic::catch_unwind`]: http://doc.rust-lang.org/nightly/std/panic/fn.catch_unwind.html
6479 [`std::panic::resume_unwind`]: http://doc.rust-lang.org/nightly/std/panic/fn.resume_unwind.html
6480 [`std::panic`]: http://doc.rust-lang.org/nightly/std/panic/index.html
6481 [`str::is_char_boundary`]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.is_char_boundary
6482
6483
6484 Version 1.8.0 (2016-04-14)
6485 ==========================
6486
6487 Language
6488 --------
6489
6490 * Rust supports overloading of compound assignment statements like
6491   `+=` by implementing the [`AddAssign`], [`SubAssign`],
6492   [`MulAssign`], [`DivAssign`], [`RemAssign`], [`BitAndAssign`],
6493   [`BitOrAssign`], [`BitXorAssign`], [`ShlAssign`], or [`ShrAssign`]
6494   traits. [RFC 953].
6495 * Empty structs can be defined with braces, as in `struct Foo { }`, in
6496   addition to the non-braced form, `struct Foo;`. [RFC 218].
6497
6498 Libraries
6499 ---------
6500
6501 * Stabilized APIs:
6502   * [`str::encode_utf16`] (renamed from `utf16_units`)
6503   * [`str::EncodeUtf16`] (renamed from `Utf16Units`)
6504   * [`Ref::map`]
6505   * [`RefMut::map`]
6506   * [`ptr::drop_in_place`]
6507   * [`time::Instant`]
6508   * [`time::SystemTime`]
6509   * [`Instant::now`]
6510   * [`Instant::duration_since`] (renamed from `duration_from_earlier`)
6511   * [`Instant::elapsed`]
6512   * [`SystemTime::now`]
6513   * [`SystemTime::duration_since`] (renamed from `duration_from_earlier`)
6514   * [`SystemTime::elapsed`]
6515   * Various `Add`/`Sub` impls for `Time` and `SystemTime`
6516   * [`SystemTimeError`]
6517   * [`SystemTimeError::duration`]
6518   * Various impls for `SystemTimeError`
6519   * [`UNIX_EPOCH`]
6520   * [`AddAssign`], [`SubAssign`], [`MulAssign`], [`DivAssign`],
6521     [`RemAssign`], [`BitAndAssign`], [`BitOrAssign`],
6522     [`BitXorAssign`], [`ShlAssign`], [`ShrAssign`].
6523 * [The `write!` and `writeln!` macros correctly emit errors if any of
6524   their arguments can't be formatted][1.8w].
6525 * [Various I/O functions support large files on 32-bit Linux][1.8l].
6526 * [The Unix-specific `raw` modules, which contain a number of
6527   redefined C types are deprecated][1.8r], including `os::raw::unix`,
6528   `os::raw::macos`, and `os::raw::linux`. These modules defined types
6529   such as `ino_t` and `dev_t`. The inconsistency of these definitions
6530   across platforms was making it difficult to implement `std`
6531   correctly. Those that need these definitions should use the `libc`
6532   crate. [RFC 1415].
6533 * The Unix-specific `MetadataExt` traits, including
6534   `os::unix::fs::MetadataExt`, which expose values such as inode
6535   numbers [no longer return platform-specific types][1.8r], but
6536   instead return widened integers. [RFC 1415].
6537 * [`btree_set::{IntoIter, Iter, Range}` are covariant][1.8cv].
6538 * [Atomic loads and stores are not volatile][1.8a].
6539 * [All types in `sync::mpsc` implement `fmt::Debug`][1.8mp].
6540
6541 Performance
6542 -----------
6543
6544 * [Inlining hash functions lead to a 3% compile-time improvement in
6545   some workloads][1.8h].
6546 * When using jemalloc, its symbols are [unprefixed so that it
6547   overrides the libc malloc implementation][1.8h]. This means that for
6548   rustc, LLVM is now using jemalloc, which results in a 6%
6549   compile-time improvement on a specific workload.
6550 * [Avoid quadratic growth in function size due to cleanups][1.8cu].
6551
6552 Misc
6553 ----
6554
6555 * [32-bit MSVC builds finally implement unwinding][1.8ms].
6556   i686-pc-windows-msvc is now considered a tier-1 platform.
6557 * [The `--print targets` flag prints a list of supported targets][1.8t].
6558 * [The `--print cfg` flag prints the `cfg`s defined for the current
6559   target][1.8cf].
6560 * [`rustc` can be built with an new Cargo-based build system, written
6561   in Rust][1.8b].  It will eventually replace Rust's Makefile-based
6562   build system. To enable it configure with `configure --rustbuild`.
6563 * [Errors for non-exhaustive `match` patterns now list up to 3 missing
6564   variants while also indicating the total number of missing variants
6565   if more than 3][1.8m].
6566 * [Executable stacks are disabled on Linux and BSD][1.8nx].
6567 * The Rust Project now publishes binary releases of the standard
6568   library for a number of tier-2 targets:
6569   `armv7-unknown-linux-gnueabihf`, `powerpc-unknown-linux-gnu`,
6570   `powerpc64-unknown-linux-gnu`, `powerpc64le-unknown-linux-gnu`
6571   `x86_64-rumprun-netbsd`. These can be installed with
6572   tools such as [multirust][1.8mr].
6573
6574 Cargo
6575 -----
6576
6577 * [`cargo init` creates a new Cargo project in the current
6578   directory][1.8ci].  It is otherwise like `cargo new`.
6579 * [Cargo has configuration keys for `-v` and
6580   `--color`][1.8cc]. `verbose` and `color`, respectively, go in the
6581   `[term]` section of `.cargo/config`.
6582 * [Configuration keys that evaluate to strings or integers can be set
6583   via environment variables][1.8ce]. For example the `build.jobs` key
6584   can be set via `CARGO_BUILD_JOBS`. Environment variables take
6585   precedence over config files.
6586 * [Target-specific dependencies support Rust `cfg` syntax for
6587   describing targets][1.8cfg] so that dependencies for multiple
6588   targets can be specified together. [RFC 1361].
6589 * [The environment variables `CARGO_TARGET_ROOT`, `RUSTC`, and
6590   `RUSTDOC` take precedence over the `build.target-dir`,
6591   `build.rustc`, and `build.rustdoc` configuration values][1.8cv].
6592 * [The child process tree is killed on Windows when Cargo is
6593   killed][1.8ck].
6594 * [The `build.target` configuration value sets the target platform,
6595   like `--target`][1.8ct].
6596
6597 Compatibility Notes
6598 -------------------
6599
6600 * [Unstable compiler flags have been further restricted][1.8u]. Since
6601   1.0 `-Z` flags have been considered unstable, and other flags that
6602   were considered unstable additionally required passing `-Z
6603   unstable-options` to access. Unlike unstable language and library
6604   features though, these options have been accessible on the stable
6605   release channel. Going forward, *new unstable flags will not be
6606   available on the stable release channel*, and old unstable flags
6607   will warn about their usage. In the future, all unstable flags will
6608   be unavailable on the stable release channel.
6609 * [It is no longer possible to `match` on empty enum variants using
6610   the `Variant(..)` syntax][1.8v]. This has been a warning since 1.6.
6611 * The Unix-specific `MetadataExt` traits, including
6612   `os::unix::fs::MetadataExt`, which expose values such as inode
6613   numbers [no longer return platform-specific types][1.8r], but
6614   instead return widened integers. [RFC 1415].
6615 * [Modules sourced from the filesystem cannot appear within arbitrary
6616   blocks, but only within other modules][1.8mf].
6617 * [`--cfg` compiler flags are parsed strictly as identifiers][1.8c].
6618 * On Unix, [stack overflow triggers a runtime abort instead of a
6619   SIGSEGV][1.8so].
6620 * [`Command::spawn` and its equivalents return an error if any of
6621   its command-line arguments contain interior `NUL`s][1.8n].
6622 * [Tuple and unit enum variants from other crates are in the type
6623   namespace][1.8tn].
6624 * [On Windows `rustc` emits `.lib` files for the `staticlib` library
6625   type instead of `.a` files][1.8st]. Additionally, for the MSVC
6626   toolchain, `rustc` emits import libraries named `foo.dll.lib`
6627   instead of `foo.lib`.
6628
6629
6630 [1.8a]: https://github.com/rust-lang/rust/pull/30962
6631 [1.8b]: https://github.com/rust-lang/rust/pull/31123
6632 [1.8c]: https://github.com/rust-lang/rust/pull/31530
6633 [1.8cc]: https://github.com/rust-lang/cargo/pull/2397
6634 [1.8ce]: https://github.com/rust-lang/cargo/pull/2398
6635 [1.8cf]: https://github.com/rust-lang/rust/pull/31278
6636 [1.8cfg]: https://github.com/rust-lang/cargo/pull/2328
6637 [1.8ci]: https://github.com/rust-lang/cargo/pull/2081
6638 [1.8ck]: https://github.com/rust-lang/cargo/pull/2370
6639 [1.8ct]: https://github.com/rust-lang/cargo/pull/2335
6640 [1.8cu]: https://github.com/rust-lang/rust/pull/31390
6641 [1.8cv]: https://github.com/rust-lang/cargo/issues/2365
6642 [1.8cv]: https://github.com/rust-lang/rust/pull/30998
6643 [1.8h]: https://github.com/rust-lang/rust/pull/31460
6644 [1.8l]: https://github.com/rust-lang/rust/pull/31668
6645 [1.8m]: https://github.com/rust-lang/rust/pull/31020
6646 [1.8mf]: https://github.com/rust-lang/rust/pull/31534
6647 [1.8mp]: https://github.com/rust-lang/rust/pull/30894
6648 [1.8mr]: https://users.rust-lang.org/t/multirust-0-8-with-cross-std-installation/4901
6649 [1.8ms]: https://github.com/rust-lang/rust/pull/30448
6650 [1.8n]: https://github.com/rust-lang/rust/pull/31056
6651 [1.8nx]: https://github.com/rust-lang/rust/pull/30859
6652 [1.8r]: https://github.com/rust-lang/rust/pull/31551
6653 [1.8so]: https://github.com/rust-lang/rust/pull/31333
6654 [1.8st]: https://github.com/rust-lang/rust/pull/29520
6655 [1.8t]: https://github.com/rust-lang/rust/pull/31358
6656 [1.8tn]: https://github.com/rust-lang/rust/pull/30882
6657 [1.8u]: https://github.com/rust-lang/rust/pull/31793
6658 [1.8v]: https://github.com/rust-lang/rust/pull/31757
6659 [1.8w]: https://github.com/rust-lang/rust/pull/31904
6660 [RFC 1361]: https://github.com/rust-lang/rfcs/blob/master/text/1361-cargo-cfg-dependencies.md
6661 [RFC 1415]: https://github.com/rust-lang/rfcs/blob/master/text/1415-trim-std-os.md
6662 [RFC 218]: https://github.com/rust-lang/rfcs/blob/master/text/0218-empty-struct-with-braces.md
6663 [RFC 953]: https://github.com/rust-lang/rfcs/blob/master/text/0953-op-assign.md
6664 [`AddAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.AddAssign.html
6665 [`BitAndAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.BitAndAssign.html
6666 [`BitOrAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.BitOrAssign.html
6667 [`BitXorAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.BitXorAssign.html
6668 [`DivAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.DivAssign.html
6669 [`Instant::duration_since`]: http://doc.rust-lang.org/nightly/std/time/struct.Instant.html#method.duration_since
6670 [`Instant::elapsed`]: http://doc.rust-lang.org/nightly/std/time/struct.Instant.html#method.elapsed
6671 [`Instant::now`]: http://doc.rust-lang.org/nightly/std/time/struct.Instant.html#method.now
6672 [`MulAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.MulAssign.html
6673 [`Ref::map`]: http://doc.rust-lang.org/nightly/std/cell/struct.Ref.html#method.map
6674 [`RefMut::map`]: http://doc.rust-lang.org/nightly/std/cell/struct.RefMut.html#method.map
6675 [`RemAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.RemAssign.html
6676 [`ShlAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.ShlAssign.html
6677 [`ShrAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.ShrAssign.html
6678 [`SubAssign`]: http://doc.rust-lang.org/nightly/std/ops/trait.SubAssign.html
6679 [`SystemTime::duration_since`]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTime.html#method.duration_since
6680 [`SystemTime::elapsed`]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTime.html#method.elapsed
6681 [`SystemTime::now`]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTime.html#method.now
6682 [`SystemTimeError::duration`]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTimeError.html#method.duration
6683 [`SystemTimeError`]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTimeError.html
6684 [`UNIX_EPOCH`]: http://doc.rust-lang.org/nightly/std/time/constant.UNIX_EPOCH.html
6685 [`ptr::drop_in_place`]: http://doc.rust-lang.org/nightly/std/ptr/fn.drop_in_place.html
6686 [`str::EncodeUtf16`]: http://doc.rust-lang.org/nightly/std/str/struct.EncodeUtf16.html
6687 [`str::encode_utf16`]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.encode_utf16
6688 [`time::Instant`]: http://doc.rust-lang.org/nightly/std/time/struct.Instant.html
6689 [`time::SystemTime`]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTime.html
6690
6691
6692 Version 1.7.0 (2016-03-03)
6693 ==========================
6694
6695 Libraries
6696 ---------
6697
6698 * Stabilized APIs
6699   * `Path`
6700     * [`Path::strip_prefix`] (renamed from relative_from)
6701     * [`path::StripPrefixError`] (new error type returned from strip_prefix)
6702   * `Ipv4Addr`
6703     * [`Ipv4Addr::is_loopback`]
6704     * [`Ipv4Addr::is_private`]
6705     * [`Ipv4Addr::is_link_local`]
6706     * [`Ipv4Addr::is_multicast`]
6707     * [`Ipv4Addr::is_broadcast`]
6708     * [`Ipv4Addr::is_documentation`]
6709   * `Ipv6Addr`
6710     * [`Ipv6Addr::is_unspecified`]
6711     * [`Ipv6Addr::is_loopback`]
6712     * [`Ipv6Addr::is_multicast`]
6713   * `Vec`
6714     * [`Vec::as_slice`]
6715     * [`Vec::as_mut_slice`]
6716   * `String`
6717     * [`String::as_str`]
6718     * [`String::as_mut_str`]
6719   * Slices
6720     * `<[T]>::`[`clone_from_slice`], which now requires the two slices to
6721     be the same length
6722     * `<[T]>::`[`sort_by_key`]
6723   * checked, saturated, and overflowing operations
6724     * [`i32::checked_rem`], [`i32::checked_neg`], [`i32::checked_shl`], [`i32::checked_shr`]
6725     * [`i32::saturating_mul`]
6726     * [`i32::overflowing_add`], [`i32::overflowing_sub`], [`i32::overflowing_mul`], [`i32::overflowing_div`]
6727     * [`i32::overflowing_rem`], [`i32::overflowing_neg`], [`i32::overflowing_shl`], [`i32::overflowing_shr`]
6728     * [`u32::checked_rem`], [`u32::checked_neg`], [`u32::checked_shl`], [`u32::checked_shl`]
6729     * [`u32::saturating_mul`]
6730     * [`u32::overflowing_add`], [`u32::overflowing_sub`], [`u32::overflowing_mul`], [`u32::overflowing_div`]
6731     * [`u32::overflowing_rem`], [`u32::overflowing_neg`], [`u32::overflowing_shl`], [`u32::overflowing_shr`]
6732     * and checked, saturated, and overflowing operations for other primitive types
6733   * FFI
6734     * [`ffi::IntoStringError`]
6735     * [`CString::into_string`]
6736     * [`CString::into_bytes`]
6737     * [`CString::into_bytes_with_nul`]
6738     * `From<CString> for Vec<u8>`
6739   * `IntoStringError`
6740     * [`IntoStringError::into_cstring`]
6741     * [`IntoStringError::utf8_error`]
6742     * `Error for IntoStringError`
6743   * Hashing
6744     * [`std::hash::BuildHasher`]
6745     * [`BuildHasher::Hasher`]
6746     * [`BuildHasher::build_hasher`]
6747     * [`std::hash::BuildHasherDefault`]
6748     * [`HashMap::with_hasher`]
6749     * [`HashMap::with_capacity_and_hasher`]
6750     * [`HashSet::with_hasher`]
6751     * [`HashSet::with_capacity_and_hasher`]
6752     * [`std::collections::hash_map::RandomState`]
6753     * [`RandomState::new`]
6754 * [Validating UTF-8 is faster by a factor of between 7 and 14x for
6755   ASCII input][1.7utf8]. This means that creating `String`s and `str`s
6756   from bytes is faster.
6757 * [The performance of `LineWriter` (and thus `io::stdout`) was
6758   improved by using `memchr` to search for newlines][1.7m].
6759 * [`f32::to_degrees` and `f32::to_radians` are stable][1.7f]. The
6760   `f64` variants were stabilized previously.
6761 * [`BTreeMap` was rewritten to use less memory and improve the performance
6762   of insertion and iteration, the latter by as much as 5x][1.7bm].
6763 * [`BTreeSet` and its iterators, `Iter`, `IntoIter`, and `Range` are
6764   covariant over their contained type][1.7bt].
6765 * [`LinkedList` and its iterators, `Iter` and `IntoIter` are covariant
6766   over their contained type][1.7ll].
6767 * [`str::replace` now accepts a `Pattern`][1.7rp], like other string
6768   searching methods.
6769 * [`Any` is implemented for unsized types][1.7a].
6770 * [`Hash` is implemented for `Duration`][1.7h].
6771
6772 Misc
6773 ----
6774
6775 * [When running tests with `--test`, rustdoc will pass `--cfg`
6776   arguments to the compiler][1.7dt].
6777 * [The compiler is built with RPATH information by default][1.7rpa].
6778   This means that it will be possible to run `rustc` when installed in
6779   unusual configurations without configuring the dynamic linker search
6780   path explicitly.
6781 * [`rustc` passes `--enable-new-dtags` to GNU ld][1.7dta]. This makes
6782   any RPATH entries (emitted with `-C rpath`) *not* take precedence
6783   over `LD_LIBRARY_PATH`.
6784
6785 Cargo
6786 -----
6787
6788 * [`cargo rustc` accepts a `--profile` flag that runs `rustc` under
6789   any of the compilation profiles, 'dev', 'bench', or 'test'][1.7cp].
6790 * [The `rerun-if-changed` build script directive no longer causes the
6791   build script to incorrectly run twice in certain scenarios][1.7rr].
6792
6793 Compatibility Notes
6794 -------------------
6795
6796 * Soundness fixes to the interactions between associated types and
6797   lifetimes, specified in [RFC 1214], [now generate errors][1.7sf] for
6798   code that violates the new rules. This is a significant change that
6799   is known to break existing code, so it has emitted warnings for the
6800   new error cases since 1.4 to give crate authors time to adapt. The
6801   details of what is changing are subtle; read the RFC for more.
6802 * [Several bugs in the compiler's visibility calculations were
6803   fixed][1.7v]. Since this was found to break significant amounts of
6804   code, the new errors will be emitted as warnings for several release
6805   cycles, under the `private_in_public` lint.
6806 * Defaulted type parameters were accidentally accepted in positions
6807   that were not intended. In this release, [defaulted type parameters
6808   appearing outside of type definitions will generate a
6809   warning][1.7d], which will become an error in future releases.
6810 * [Parsing "." as a float results in an error instead of 0][1.7p].
6811   That is, `".".parse::<f32>()` returns `Err`, not `Ok(0.0)`.
6812 * [Borrows of closure parameters may not outlive the closure][1.7bc].
6813
6814 [1.7a]: https://github.com/rust-lang/rust/pull/30928
6815 [1.7bc]: https://github.com/rust-lang/rust/pull/30341
6816 [1.7bm]: https://github.com/rust-lang/rust/pull/30426
6817 [1.7bt]: https://github.com/rust-lang/rust/pull/30998
6818 [1.7cp]: https://github.com/rust-lang/cargo/pull/2224
6819 [1.7d]: https://github.com/rust-lang/rust/pull/30724
6820 [1.7dt]: https://github.com/rust-lang/rust/pull/30372
6821 [1.7dta]: https://github.com/rust-lang/rust/pull/30394
6822 [1.7f]: https://github.com/rust-lang/rust/pull/30672
6823 [1.7h]: https://github.com/rust-lang/rust/pull/30818
6824 [1.7ll]: https://github.com/rust-lang/rust/pull/30663
6825 [1.7m]: https://github.com/rust-lang/rust/pull/30381
6826 [1.7p]: https://github.com/rust-lang/rust/pull/30681
6827 [1.7rp]: https://github.com/rust-lang/rust/pull/29498
6828 [1.7rpa]: https://github.com/rust-lang/rust/pull/30353
6829 [1.7rr]: https://github.com/rust-lang/cargo/pull/2279
6830 [1.7sf]: https://github.com/rust-lang/rust/pull/30389
6831 [1.7utf8]: https://github.com/rust-lang/rust/pull/30740
6832 [1.7v]: https://github.com/rust-lang/rust/pull/29973
6833 [RFC 1214]: https://github.com/rust-lang/rfcs/blob/master/text/1214-projections-lifetimes-and-wf.md
6834 [`BuildHasher::Hasher`]: http://doc.rust-lang.org/nightly/std/hash/trait.Hasher.html
6835 [`BuildHasher::build_hasher`]: http://doc.rust-lang.org/nightly/std/hash/trait.BuildHasher.html#tymethod.build_hasher
6836 [`CString::into_bytes_with_nul`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CString.html#method.into_bytes_with_nul
6837 [`CString::into_bytes`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CString.html#method.into_bytes
6838 [`CString::into_string`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CString.html#method.into_string
6839 [`HashMap::with_capacity_and_hasher`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashMap.html#method.with_capacity_and_hasher
6840 [`HashMap::with_hasher`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashMap.html#method.with_hasher
6841 [`HashSet::with_capacity_and_hasher`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashSet.html#method.with_capacity_and_hasher
6842 [`HashSet::with_hasher`]: http://doc.rust-lang.org/nightly/std/collections/struct.HashSet.html#method.with_hasher
6843 [`IntoStringError::into_cstring`]: http://doc.rust-lang.org/nightly/std/ffi/struct.IntoStringError.html#method.into_cstring
6844 [`IntoStringError::utf8_error`]: http://doc.rust-lang.org/nightly/std/ffi/struct.IntoStringError.html#method.utf8_error
6845 [`Ipv4Addr::is_broadcast`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#method.is_broadcast
6846 [`Ipv4Addr::is_documentation`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#method.is_documentation
6847 [`Ipv4Addr::is_link_local`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#method.is_link_local
6848 [`Ipv4Addr::is_loopback`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#method.is_loopback
6849 [`Ipv4Addr::is_multicast`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#method.is_multicast
6850 [`Ipv4Addr::is_private`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#method.is_private
6851 [`Ipv6Addr::is_loopback`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv6Addr.html#method.is_loopback
6852 [`Ipv6Addr::is_multicast`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv6Addr.html#method.is_multicast
6853 [`Ipv6Addr::is_unspecified`]: http://doc.rust-lang.org/nightly/std/net/struct.Ipv6Addr.html#method.is_unspecified
6854 [`Path::strip_prefix`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.strip_prefix
6855 [`RandomState::new`]: http://doc.rust-lang.org/nightly/std/collections/hash_map/struct.RandomState.html#method.new
6856 [`String::as_mut_str`]: http://doc.rust-lang.org/nightly/std/string/struct.String.html#method.as_mut_str
6857 [`String::as_str`]: http://doc.rust-lang.org/nightly/std/string/struct.String.html#method.as_str
6858 [`Vec::as_mut_slice`]: http://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#method.as_mut_slice
6859 [`Vec::as_slice`]: http://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#method.as_slice
6860 [`clone_from_slice`]: http://doc.rust-lang.org/nightly/std/primitive.slice.html#method.clone_from_slice
6861 [`ffi::IntoStringError`]: http://doc.rust-lang.org/nightly/std/ffi/struct.IntoStringError.html
6862 [`i32::checked_neg`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.checked_neg
6863 [`i32::checked_rem`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.checked_rem
6864 [`i32::checked_shl`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.checked_shl
6865 [`i32::checked_shr`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.checked_shr
6866 [`i32::overflowing_add`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.overflowing_add
6867 [`i32::overflowing_div`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.overflowing_div
6868 [`i32::overflowing_mul`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.overflowing_mul
6869 [`i32::overflowing_neg`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.overflowing_neg
6870 [`i32::overflowing_rem`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.overflowing_rem
6871 [`i32::overflowing_shl`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.overflowing_shl
6872 [`i32::overflowing_shr`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.overflowing_shr
6873 [`i32::overflowing_sub`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.overflowing_sub
6874 [`i32::saturating_mul`]: http://doc.rust-lang.org/nightly/std/primitive.i32.html#method.saturating_mul
6875 [`path::StripPrefixError`]: http://doc.rust-lang.org/nightly/std/path/struct.StripPrefixError.html
6876 [`sort_by_key`]: http://doc.rust-lang.org/nightly/std/primitive.slice.html#method.sort_by_key
6877 [`std::collections::hash_map::RandomState`]: http://doc.rust-lang.org/nightly/std/collections/hash_map/struct.RandomState.html
6878 [`std::hash::BuildHasherDefault`]: http://doc.rust-lang.org/nightly/std/hash/struct.BuildHasherDefault.html
6879 [`std::hash::BuildHasher`]: http://doc.rust-lang.org/nightly/std/hash/trait.BuildHasher.html
6880 [`u32::checked_neg`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.checked_neg
6881 [`u32::checked_rem`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.checked_rem
6882 [`u32::checked_neg`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.checked_neg
6883 [`u32::checked_shl`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.checked_shl
6884 [`u32::overflowing_add`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.overflowing_add
6885 [`u32::overflowing_div`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.overflowing_div
6886 [`u32::overflowing_mul`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.overflowing_mul
6887 [`u32::overflowing_neg`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.overflowing_neg
6888 [`u32::overflowing_rem`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.overflowing_rem
6889 [`u32::overflowing_shl`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.overflowing_shl
6890 [`u32::overflowing_shr`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.overflowing_shr
6891 [`u32::overflowing_sub`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.overflowing_sub
6892 [`u32::saturating_mul`]: http://doc.rust-lang.org/nightly/std/primitive.u32.html#method.saturating_mul
6893
6894
6895 Version 1.6.0 (2016-01-21)
6896 ==========================
6897
6898 Language
6899 --------
6900
6901 * The `#![no_std]` attribute causes a crate to not be linked to the
6902   standard library, but only the [core library][1.6co], as described
6903   in [RFC 1184]. The core library defines common types and traits but
6904   has no platform dependencies whatsoever, and is the basis for Rust
6905   software in environments that cannot support a full port of the
6906   standard library, such as operating systems. Most of the core
6907   library is now stable.
6908
6909 Libraries
6910 ---------
6911
6912 * Stabilized APIs:
6913   [`Read::read_exact`],
6914   [`ErrorKind::UnexpectedEof`] (renamed from `UnexpectedEOF`),
6915   [`fs::DirBuilder`], [`fs::DirBuilder::new`],
6916   [`fs::DirBuilder::recursive`], [`fs::DirBuilder::create`],
6917   [`os::unix::fs::DirBuilderExt`],
6918   [`os::unix::fs::DirBuilderExt::mode`], [`vec::Drain`],
6919   [`vec::Vec::drain`], [`string::Drain`], [`string::String::drain`],
6920   [`vec_deque::Drain`], [`vec_deque::VecDeque::drain`],
6921   [`collections::hash_map::Drain`],
6922   [`collections::hash_map::HashMap::drain`],
6923   [`collections::hash_set::Drain`],
6924   [`collections::hash_set::HashSet::drain`],
6925   [`collections::binary_heap::Drain`],
6926   [`collections::binary_heap::BinaryHeap::drain`],
6927   [`Vec::extend_from_slice`] (renamed from `push_all`),
6928   [`Mutex::get_mut`], [`Mutex::into_inner`], [`RwLock::get_mut`],
6929   [`RwLock::into_inner`],
6930   [`Iterator::min_by_key`] (renamed from `min_by`),
6931   [`Iterator::max_by_key`] (renamed from `max_by`).
6932 * The [core library][1.6co] is stable, as are most of its APIs.
6933 * [The `assert_eq!` macro supports arguments that don't implement
6934   `Sized`][1.6ae], such as arrays. In this way it behaves more like
6935   `assert!`.
6936 * Several timer functions that take duration in milliseconds [are
6937   deprecated in favor of those that take `Duration`][1.6ms]. These
6938   include `Condvar::wait_timeout_ms`, `thread::sleep_ms`, and
6939   `thread::park_timeout_ms`.
6940 * The algorithm by which `Vec` reserves additional elements was
6941   [tweaked to not allocate excessive space][1.6a] while still growing
6942   exponentially.
6943 * `From` conversions are [implemented from integers to floats][1.6f]
6944   in cases where the conversion is lossless. Thus they are not
6945   implemented for 32-bit ints to `f32`, nor for 64-bit ints to `f32`
6946   or `f64`. They are also not implemented for `isize` and `usize`
6947   because the implementations would be platform-specific. `From` is
6948   also implemented from `f32` to `f64`.
6949 * `From<&Path>` and `From<PathBuf>` are implemented for `Cow<Path>`.
6950 * `From<T>` is implemented for `Box<T>`, `Rc<T>` and `Arc<T>`.
6951 * `IntoIterator` is implemented for `&PathBuf` and `&Path`.
6952 * [`BinaryHeap` was refactored][1.6bh] for modest performance
6953   improvements.
6954 * Sorting slices that are already sorted [is 50% faster in some
6955   cases][1.6s].
6956
6957 Cargo
6958 -----
6959
6960 * Cargo will look in `$CARGO_HOME/bin` for subcommands [by default][1.6c].
6961 * Cargo build scripts can specify their dependencies by emitting the
6962   [`rerun-if-changed`][1.6rr] key.
6963 * crates.io will reject publication of crates with dependencies that
6964   have a wildcard version constraint. Crates with wildcard
6965   dependencies were seen to cause a variety of problems, as described
6966   in [RFC 1241]. Since 1.5 publication of such crates has emitted a
6967   warning.
6968 * `cargo clean` [accepts a `--release` flag][1.6cc] to clean the
6969   release folder.  A variety of artifacts that Cargo failed to clean
6970   are now correctly deleted.
6971
6972 Misc
6973 ----
6974
6975 * The `unreachable_code` lint [warns when a function call's argument
6976   diverges][1.6dv].
6977 * The parser indicates [failures that may be caused by
6978   confusingly-similar Unicode characters][1.6uc]
6979 * Certain macro errors [are reported at definition time][1.6m], not
6980   expansion.
6981
6982 Compatibility Notes
6983 -------------------
6984
6985 * The compiler no longer makes use of the [`RUST_PATH`][1.6rp]
6986   environment variable when locating crates. This was a pre-cargo
6987   feature for integrating with the package manager that was
6988   accidentally never removed.
6989 * [A number of bugs were fixed in the privacy checker][1.6p] that
6990   could cause previously-accepted code to break.
6991 * [Modules and unit/tuple structs may not share the same name][1.6ts].
6992 * [Bugs in pattern matching unit structs were fixed][1.6us]. The tuple
6993   struct pattern syntax (`Foo(..)`) can no longer be used to match
6994   unit structs. This is a warning now, but will become an error in
6995   future releases. Patterns that share the same name as a const are
6996   now an error.
6997 * A bug was fixed that causes [rustc not to apply default type
6998   parameters][1.6xc] when resolving certain method implementations of
6999   traits defined in other crates.
7000
7001 [1.6a]: https://github.com/rust-lang/rust/pull/29454
7002 [1.6ae]: https://github.com/rust-lang/rust/pull/29770
7003 [1.6bh]: https://github.com/rust-lang/rust/pull/29811
7004 [1.6c]: https://github.com/rust-lang/cargo/pull/2192
7005 [1.6cc]: https://github.com/rust-lang/cargo/pull/2131
7006 [1.6co]: http://doc.rust-lang.org/core/index.html
7007 [1.6dv]: https://github.com/rust-lang/rust/pull/30000
7008 [1.6f]: https://github.com/rust-lang/rust/pull/29129
7009 [1.6m]: https://github.com/rust-lang/rust/pull/29828
7010 [1.6ms]: https://github.com/rust-lang/rust/pull/29604
7011 [1.6p]: https://github.com/rust-lang/rust/pull/29726
7012 [1.6rp]: https://github.com/rust-lang/rust/pull/30034
7013 [1.6rr]: https://github.com/rust-lang/cargo/pull/2134
7014 [1.6s]: https://github.com/rust-lang/rust/pull/29675
7015 [1.6ts]: https://github.com/rust-lang/rust/issues/21546
7016 [1.6uc]: https://github.com/rust-lang/rust/pull/29837
7017 [1.6us]: https://github.com/rust-lang/rust/pull/29383
7018 [1.6xc]: https://github.com/rust-lang/rust/issues/30123
7019 [RFC 1184]: https://github.com/rust-lang/rfcs/blob/master/text/1184-stabilize-no_std.md
7020 [RFC 1241]: https://github.com/rust-lang/rfcs/blob/master/text/1241-no-wildcard-deps.md
7021 [`ErrorKind::UnexpectedEof`]: http://doc.rust-lang.org/nightly/std/io/enum.ErrorKind.html#variant.UnexpectedEof
7022 [`Iterator::max_by_key`]: http://doc.rust-lang.org/nightly/std/iter/trait.Iterator.html#method.max_by_key
7023 [`Iterator::min_by_key`]: http://doc.rust-lang.org/nightly/std/iter/trait.Iterator.html#method.min_by_key
7024 [`Mutex::get_mut`]: http://doc.rust-lang.org/nightly/std/sync/struct.Mutex.html#method.get_mut
7025 [`Mutex::into_inner`]: http://doc.rust-lang.org/nightly/std/sync/struct.Mutex.html#method.into_inner
7026 [`Read::read_exact`]: http://doc.rust-lang.org/nightly/std/io/trait.Read.html#method.read_exact
7027 [`RwLock::get_mut`]: http://doc.rust-lang.org/nightly/std/sync/struct.RwLock.html#method.get_mut
7028 [`RwLock::into_inner`]: http://doc.rust-lang.org/nightly/std/sync/struct.RwLock.html#method.into_inner
7029 [`Vec::extend_from_slice`]: http://doc.rust-lang.org/nightly/collections/vec/struct.Vec.html#method.extend_from_slice
7030 [`collections::binary_heap::BinaryHeap::drain`]: http://doc.rust-lang.org/nightly/std/collections/binary_heap/struct.BinaryHeap.html#method.drain
7031 [`collections::binary_heap::Drain`]: http://doc.rust-lang.org/nightly/std/collections/binary_heap/struct.Drain.html
7032 [`collections::hash_map::Drain`]: http://doc.rust-lang.org/nightly/std/collections/hash_map/struct.Drain.html
7033 [`collections::hash_map::HashMap::drain`]: http://doc.rust-lang.org/nightly/std/collections/hash_map/struct.HashMap.html#method.drain
7034 [`collections::hash_set::Drain`]: http://doc.rust-lang.org/nightly/std/collections/hash_set/struct.Drain.html
7035 [`collections::hash_set::HashSet::drain`]: http://doc.rust-lang.org/nightly/std/collections/hash_set/struct.HashSet.html#method.drain
7036 [`fs::DirBuilder::create`]: http://doc.rust-lang.org/nightly/std/fs/struct.DirBuilder.html#method.create
7037 [`fs::DirBuilder::new`]: http://doc.rust-lang.org/nightly/std/fs/struct.DirBuilder.html#method.new
7038 [`fs::DirBuilder::recursive`]: http://doc.rust-lang.org/nightly/std/fs/struct.DirBuilder.html#method.recursive
7039 [`fs::DirBuilder`]: http://doc.rust-lang.org/nightly/std/fs/struct.DirBuilder.html
7040 [`os::unix::fs::DirBuilderExt::mode`]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.DirBuilderExt.html#tymethod.mode
7041 [`os::unix::fs::DirBuilderExt`]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.DirBuilderExt.html
7042 [`string::Drain`]: http://doc.rust-lang.org/nightly/std/string/struct.Drain.html
7043 [`string::String::drain`]: http://doc.rust-lang.org/nightly/std/string/struct.String.html#method.drain
7044 [`vec::Drain`]: http://doc.rust-lang.org/nightly/std/vec/struct.Drain.html
7045 [`vec::Vec::drain`]: http://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#method.drain
7046 [`vec_deque::Drain`]: http://doc.rust-lang.org/nightly/std/collections/vec_deque/struct.Drain.html
7047 [`vec_deque::VecDeque::drain`]: http://doc.rust-lang.org/nightly/std/collections/vec_deque/struct.VecDeque.html#method.drain
7048
7049
7050 Version 1.5.0 (2015-12-10)
7051 ==========================
7052
7053 * ~700 changes, numerous bugfixes
7054
7055 Highlights
7056 ----------
7057
7058 * Stabilized APIs:
7059   [`BinaryHeap::from`], [`BinaryHeap::into_sorted_vec`],
7060   [`BinaryHeap::into_vec`], [`Condvar::wait_timeout`],
7061   [`FileTypeExt::is_block_device`], [`FileTypeExt::is_char_device`],
7062   [`FileTypeExt::is_fifo`], [`FileTypeExt::is_socket`],
7063   [`FileTypeExt`], [`Formatter::alternate`], [`Formatter::fill`],
7064   [`Formatter::precision`], [`Formatter::sign_aware_zero_pad`],
7065   [`Formatter::sign_minus`], [`Formatter::sign_plus`],
7066   [`Formatter::width`], [`Iterator::cmp`], [`Iterator::eq`],
7067   [`Iterator::ge`], [`Iterator::gt`], [`Iterator::le`],
7068   [`Iterator::lt`], [`Iterator::ne`], [`Iterator::partial_cmp`],
7069   [`Path::canonicalize`], [`Path::exists`], [`Path::is_dir`],
7070   [`Path::is_file`], [`Path::metadata`], [`Path::read_dir`],
7071   [`Path::read_link`], [`Path::symlink_metadata`],
7072   [`Utf8Error::valid_up_to`], [`Vec::resize`],
7073   [`VecDeque::as_mut_slices`], [`VecDeque::as_slices`],
7074   [`VecDeque::insert`], [`VecDeque::shrink_to_fit`],
7075   [`VecDeque::swap_remove_back`], [`VecDeque::swap_remove_front`],
7076   [`slice::split_first_mut`], [`slice::split_first`],
7077   [`slice::split_last_mut`], [`slice::split_last`],
7078   [`char::from_u32_unchecked`], [`fs::canonicalize`],
7079   [`str::MatchIndices`], [`str::RMatchIndices`],
7080   [`str::match_indices`], [`str::rmatch_indices`],
7081   [`str::slice_mut_unchecked`], [`string::ParseError`].
7082 * Rust applications hosted on crates.io can be installed locally to
7083   `~/.cargo/bin` with the [`cargo install`] command. Among other
7084   things this makes it easier to augment Cargo with new subcommands:
7085   when a binary named e.g. `cargo-foo` is found in `$PATH` it can be
7086   invoked as `cargo foo`.
7087 * Crates with wildcard (`*`) dependencies will [emit warnings when
7088   published][1.5w]. In 1.6 it will no longer be possible to publish
7089   crates with wildcard dependencies.
7090
7091 Breaking Changes
7092 ----------------
7093
7094 * The rules determining when a particular lifetime must outlive
7095   a particular value (known as '[dropck]') have been [modified
7096   to not rely on parametricity][1.5p].
7097 * [Implementations of `AsRef` and `AsMut` were added to `Box`, `Rc`,
7098   and `Arc`][1.5a]. Because these smart pointer types implement
7099   `Deref`, this causes breakage in cases where the interior type
7100   contains methods of the same name.
7101 * [Correct a bug in Rc/Arc][1.5c] that caused [dropck] to be unaware
7102   that they could drop their content. Soundness fix.
7103 * All method invocations are [properly checked][1.5wf1] for
7104   [well-formedness][1.5wf2]. Soundness fix.
7105 * Traits whose supertraits contain `Self` are [not object
7106   safe][1.5o]. Soundness fix.
7107 * Target specifications support a [`no_default_libraries`][1.5nd]
7108   setting that controls whether `-nodefaultlibs` is passed to the
7109   linker, and in turn the `is_like_windows` setting no longer affects
7110   the `-nodefaultlibs` flag.
7111 * `#[derive(Show)]`, long-deprecated, [has been removed][1.5ds].
7112 * The `#[inline]` and `#[repr]` attributes [can only appear
7113   in valid locations][1.5at].
7114 * Native libraries linked from the local crate are [passed to
7115   the linker before native libraries from upstream crates][1.5nl].
7116 * Two rarely-used attributes, `#[no_debug]` and
7117   `#[omit_gdb_pretty_printer_section]` [are feature gated][1.5fg].
7118 * Negation of unsigned integers, which has been a warning for
7119   several releases, [is now behind a feature gate and will
7120   generate errors][1.5nu].
7121 * The parser accidentally accepted visibility modifiers on
7122   enum variants, a bug [which has been fixed][1.5ev].
7123 * [A bug was fixed that allowed `use` statements to import unstable
7124   features][1.5use].
7125
7126 Language
7127 --------
7128
7129 * When evaluating expressions at compile-time that are not
7130   compile-time constants (const-evaluating expressions in non-const
7131   contexts), incorrect code such as overlong bitshifts and arithmetic
7132   overflow will [generate a warning instead of an error][1.5ce],
7133   delaying the error until runtime. This will allow the
7134   const-evaluator to be expanded in the future backwards-compatibly.
7135 * The `improper_ctypes` lint [no longer warns about using `isize` and
7136   `usize` in FFI][1.5ict].
7137
7138 Libraries
7139 ---------
7140
7141 * `Arc<T>` and `Rc<T>` are [covariant with respect to `T` instead of
7142   invariant][1.5c].
7143 * `Default` is [implemented for mutable slices][1.5d].
7144 * `FromStr` is [implemented for `SockAddrV4` and `SockAddrV6`][1.5s].
7145 * There are now `From` conversions [between floating point
7146   types][1.5f] where the conversions are lossless.
7147 * There are now `From` conversions [between integer types][1.5i] where
7148   the conversions are lossless.
7149 * [`fs::Metadata` implements `Clone`][1.5fs].
7150 * The `parse` method [accepts a leading "+" when parsing
7151   integers][1.5pi].
7152 * [`AsMut` is implemented for `Vec`][1.5am].
7153 * The `clone_from` implementations for `String` and `BinaryHeap` [have
7154   been optimized][1.5cf] and no longer rely on the default impl.
7155 * The `extern "Rust"`, `extern "C"`, `unsafe extern "Rust"` and
7156   `unsafe extern "C"` function types now [implement `Clone`,
7157   `PartialEq`, `Eq`, `PartialOrd`, `Ord`, `Hash`, `fmt::Pointer`, and
7158   `fmt::Debug` for up to 12 arguments][1.5fp].
7159 * [Dropping `Vec`s is much faster in unoptimized builds when the
7160   element types don't implement `Drop`][1.5dv].
7161 * A bug that caused in incorrect behavior when [combining `VecDeque`
7162   with zero-sized types][1.5vdz] was resolved.
7163 * [`PartialOrd` for slices is faster][1.5po].
7164
7165 Miscellaneous
7166 -------------
7167
7168 * [Crate metadata size was reduced by 20%][1.5md].
7169 * [Improvements to code generation reduced the size of libcore by 3.3
7170   MB and rustc's memory usage by 18MB][1.5m].
7171 * [Improvements to deref translation increased performance in
7172   unoptimized builds][1.5dr].
7173 * Various errors in trait resolution [are deduplicated to only be
7174   reported once][1.5te].
7175 * Rust has preliminary [support for rumprun kernels][1.5rr].
7176 * Rust has preliminary [support for NetBSD on amd64][1.5na].
7177
7178 [1.5use]: https://github.com/rust-lang/rust/pull/28364
7179 [1.5po]: https://github.com/rust-lang/rust/pull/28436
7180 [1.5ev]: https://github.com/rust-lang/rust/pull/28442
7181 [1.5nu]: https://github.com/rust-lang/rust/pull/28468
7182 [1.5dr]: https://github.com/rust-lang/rust/pull/28491
7183 [1.5vdz]: https://github.com/rust-lang/rust/pull/28494
7184 [1.5md]: https://github.com/rust-lang/rust/pull/28521
7185 [1.5fg]: https://github.com/rust-lang/rust/pull/28522
7186 [1.5dv]: https://github.com/rust-lang/rust/pull/28531
7187 [1.5na]: https://github.com/rust-lang/rust/pull/28543
7188 [1.5fp]: https://github.com/rust-lang/rust/pull/28560
7189 [1.5rr]: https://github.com/rust-lang/rust/pull/28593
7190 [1.5cf]: https://github.com/rust-lang/rust/pull/28602
7191 [1.5nl]: https://github.com/rust-lang/rust/pull/28605
7192 [1.5te]: https://github.com/rust-lang/rust/pull/28645
7193 [1.5at]: https://github.com/rust-lang/rust/pull/28650
7194 [1.5am]: https://github.com/rust-lang/rust/pull/28663
7195 [1.5m]: https://github.com/rust-lang/rust/pull/28778
7196 [1.5ict]: https://github.com/rust-lang/rust/pull/28779
7197 [1.5a]: https://github.com/rust-lang/rust/pull/28811
7198 [1.5pi]: https://github.com/rust-lang/rust/pull/28826
7199 [1.5ce]: https://github.com/rust-lang/rfcs/blob/master/text/1229-compile-time-asserts.md
7200 [1.5p]: https://github.com/rust-lang/rfcs/blob/master/text/1238-nonparametric-dropck.md
7201 [1.5i]: https://github.com/rust-lang/rust/pull/28921
7202 [1.5fs]: https://github.com/rust-lang/rust/pull/29021
7203 [1.5f]: https://github.com/rust-lang/rust/pull/29129
7204 [1.5ds]: https://github.com/rust-lang/rust/pull/29148
7205 [1.5s]: https://github.com/rust-lang/rust/pull/29190
7206 [1.5d]: https://github.com/rust-lang/rust/pull/29245
7207 [1.5o]: https://github.com/rust-lang/rust/pull/29259
7208 [1.5nd]: https://github.com/rust-lang/rust/pull/28578
7209 [1.5wf2]: https://github.com/rust-lang/rfcs/blob/master/text/1214-projections-lifetimes-and-wf.md
7210 [1.5wf1]: https://github.com/rust-lang/rust/pull/28669
7211 [dropck]: https://doc.rust-lang.org/nightly/nomicon/dropck.html
7212 [1.5c]: https://github.com/rust-lang/rust/pull/29110
7213 [1.5w]: https://github.com/rust-lang/rfcs/blob/master/text/1241-no-wildcard-deps.md
7214 [`cargo install`]: https://github.com/rust-lang/rfcs/blob/master/text/1200-cargo-install.md
7215 [`BinaryHeap::from`]: http://doc.rust-lang.org/nightly/std/convert/trait.From.html#method.from
7216 [`BinaryHeap::into_sorted_vec`]: http://doc.rust-lang.org/nightly/std/collections/struct.BinaryHeap.html#method.into_sorted_vec
7217 [`BinaryHeap::into_vec`]: http://doc.rust-lang.org/nightly/std/collections/struct.BinaryHeap.html#method.into_vec
7218 [`Condvar::wait_timeout`]: http://doc.rust-lang.org/nightly/std/sync/struct.Condvar.html#method.wait_timeout
7219 [`FileTypeExt::is_block_device`]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.FileTypeExt.html#tymethod.is_block_device
7220 [`FileTypeExt::is_char_device`]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.FileTypeExt.html#tymethod.is_char_device
7221 [`FileTypeExt::is_fifo`]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.FileTypeExt.html#tymethod.is_fifo
7222 [`FileTypeExt::is_socket`]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.FileTypeExt.html#tymethod.is_socket
7223 [`FileTypeExt`]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.FileTypeExt.html
7224 [`Formatter::alternate`]: http://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.alternate
7225 [`Formatter::fill`]: http://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.fill
7226 [`Formatter::precision`]: http://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.precision
7227 [`Formatter::sign_aware_zero_pad`]: http://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.sign_aware_zero_pad
7228 [`Formatter::sign_minus`]: http://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.sign_minus
7229 [`Formatter::sign_plus`]: http://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.sign_plus
7230 [`Formatter::width`]: http://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.width
7231 [`Iterator::cmp`]: http://doc.rust-lang.org/nightly/core/iter/trait.Iterator.html#method.cmp
7232 [`Iterator::eq`]: http://doc.rust-lang.org/nightly/core/iter/trait.Iterator.html#method.eq
7233 [`Iterator::ge`]: http://doc.rust-lang.org/nightly/core/iter/trait.Iterator.html#method.ge
7234 [`Iterator::gt`]: http://doc.rust-lang.org/nightly/core/iter/trait.Iterator.html#method.gt
7235 [`Iterator::le`]: http://doc.rust-lang.org/nightly/core/iter/trait.Iterator.html#method.le
7236 [`Iterator::lt`]: http://doc.rust-lang.org/nightly/core/iter/trait.Iterator.html#method.lt
7237 [`Iterator::ne`]: http://doc.rust-lang.org/nightly/core/iter/trait.Iterator.html#method.ne
7238 [`Iterator::partial_cmp`]: http://doc.rust-lang.org/nightly/core/iter/trait.Iterator.html#method.partial_cmp
7239 [`Path::canonicalize`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.canonicalize
7240 [`Path::exists`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.exists
7241 [`Path::is_dir`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.is_dir
7242 [`Path::is_file`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.is_file
7243 [`Path::metadata`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.metadata
7244 [`Path::read_dir`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.read_dir
7245 [`Path::read_link`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.read_link
7246 [`Path::symlink_metadata`]: http://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.symlink_metadata
7247 [`Utf8Error::valid_up_to`]: http://doc.rust-lang.org/nightly/core/str/struct.Utf8Error.html#method.valid_up_to
7248 [`Vec::resize`]: http://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#method.resize
7249 [`VecDeque::as_mut_slices`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.as_mut_slices
7250 [`VecDeque::as_slices`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.as_slices
7251 [`VecDeque::insert`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.insert
7252 [`VecDeque::shrink_to_fit`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.shrink_to_fit
7253 [`VecDeque::swap_remove_back`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.swap_remove_back
7254 [`VecDeque::swap_remove_front`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.swap_remove_front
7255 [`slice::split_first_mut`]: http://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_first_mut
7256 [`slice::split_first`]: http://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_first
7257 [`slice::split_last_mut`]: http://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_last_mut
7258 [`slice::split_last`]: http://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_last
7259 [`char::from_u32_unchecked`]: http://doc.rust-lang.org/nightly/std/char/fn.from_u32_unchecked.html
7260 [`fs::canonicalize`]: http://doc.rust-lang.org/nightly/std/fs/fn.canonicalize.html
7261 [`str::MatchIndices`]: http://doc.rust-lang.org/nightly/std/str/struct.MatchIndices.html
7262 [`str::RMatchIndices`]: http://doc.rust-lang.org/nightly/std/str/struct.RMatchIndices.html
7263 [`str::match_indices`]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.match_indices
7264 [`str::rmatch_indices`]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.rmatch_indices
7265 [`str::slice_mut_unchecked`]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.slice_mut_unchecked
7266 [`string::ParseError`]: http://doc.rust-lang.org/nightly/std/string/enum.ParseError.html
7267
7268 Version 1.4.0 (2015-10-29)
7269 ==========================
7270
7271 * ~1200 changes, numerous bugfixes
7272
7273 Highlights
7274 ----------
7275
7276 * Windows builds targeting the 64-bit MSVC ABI and linker (instead of
7277   GNU) are now supported and recommended for use.
7278
7279 Breaking Changes
7280 ----------------
7281
7282 * [Several changes have been made to fix type soundness and improve
7283   the behavior of associated types][sound]. See [RFC 1214]. Although
7284   we have mostly introduced these changes as warnings this release, to
7285   become errors next release, there are still some scenarios that will
7286   see immediate breakage.
7287 * [The `str::lines` and `BufRead::lines` iterators treat `\r\n` as
7288   line breaks in addition to `\n`][crlf].
7289 * [Loans of `'static` lifetime extend to the end of a function][stat].
7290 * [`str::parse` no longer introduces avoidable rounding error when
7291   parsing floating point numbers. Together with earlier changes to
7292   float formatting/output, "round trips" like f.to_string().parse()
7293   now preserve the value of f exactly. Additionally, leading plus
7294   signs are now accepted][fp3].
7295
7296
7297 Language
7298 --------
7299
7300 * `use` statements that import multiple items [can now rename
7301   them][i], as in `use foo::{bar as kitten, baz as puppy}`.
7302 * [Binops work correctly on fat pointers][binfat].
7303 * `pub extern crate`, which does not behave as expected, [issues a
7304   warning][pec] until a better solution is found.
7305
7306 Libraries
7307 ---------
7308
7309 * [Many APIs were stabilized][stab]: `<Box<str>>::into_string`,
7310   [`Arc::downgrade`], [`Arc::get_mut`], [`Arc::make_mut`],
7311   [`Arc::try_unwrap`], [`Box::from_raw`], [`Box::into_raw`], [`CStr::to_str`],
7312   [`CStr::to_string_lossy`], [`CString::from_raw`], [`CString::into_raw`],
7313   [`IntoRawFd::into_raw_fd`], [`IntoRawFd`],
7314   `IntoRawHandle::into_raw_handle`, `IntoRawHandle`,
7315   `IntoRawSocket::into_raw_socket`, `IntoRawSocket`, [`Rc::downgrade`],
7316   [`Rc::get_mut`], [`Rc::make_mut`], [`Rc::try_unwrap`], [`Result::expect`],
7317   [`String::into_boxed_str`], [`TcpStream::read_timeout`],
7318   [`TcpStream::set_read_timeout`], [`TcpStream::set_write_timeout`],
7319   [`TcpStream::write_timeout`], [`UdpSocket::read_timeout`],
7320   [`UdpSocket::set_read_timeout`], [`UdpSocket::set_write_timeout`],
7321   [`UdpSocket::write_timeout`], `Vec::append`, `Vec::split_off`,
7322   [`VecDeque::append`], [`VecDeque::retain`], [`VecDeque::split_off`],
7323   [`rc::Weak::upgrade`], [`rc::Weak`], [`slice::Iter::as_slice`],
7324   [`slice::IterMut::into_slice`], [`str::CharIndices::as_str`],
7325   [`str::Chars::as_str`], [`str::split_at_mut`], [`str::split_at`],
7326   [`sync::Weak::upgrade`], [`sync::Weak`], [`thread::park_timeout`],
7327   [`thread::sleep`].
7328 * [Some APIs were deprecated][dep]: `BTreeMap::with_b`,
7329   `BTreeSet::with_b`, `Option::as_mut_slice`, `Option::as_slice`,
7330   `Result::as_mut_slice`, `Result::as_slice`, `f32::from_str_radix`,
7331   `f64::from_str_radix`.
7332 * [Reverse-searching strings is faster with the 'two-way'
7333   algorithm][s].
7334 * [`std::io::copy` allows `?Sized` arguments][cc].
7335 * The `Windows`, `Chunks`, and `ChunksMut` iterators over slices all
7336   [override `count`, `nth` and `last` with an O(1)
7337   implementation][it].
7338 * [`Default` is implemented for arrays up to `[T; 32]`][d].
7339 * [`IntoRawFd` has been added to the Unix-specific prelude,
7340   `IntoRawSocket` and `IntoRawHandle` to the Windows-specific
7341   prelude][pr].
7342 * [`Extend<String>` and `FromIterator<String` are both implemented for
7343   `String`][es].
7344 * [`IntoIterator` is implemented for references to `Option` and
7345   `Result`][into2].
7346 * [`HashMap` and `HashSet` implement `Extend<&T>` where `T:
7347   Copy`][ext] as part of [RFC 839]. This will cause type inference
7348   breakage in rare situations.
7349 * [`BinaryHeap` implements `Debug`][bh2].
7350 * [`Borrow` and `BorrowMut` are implemented for fixed-size
7351   arrays][bm].
7352 * [`extern fn`s with the "Rust" and "C" ABIs implement common
7353   traits including `Eq`, `Ord`, `Debug`, `Hash`][fp].
7354 * [String comparison is faster][faststr].
7355 * `&mut T` where `T: std::fmt::Write` [also implements
7356   `std::fmt::Write`][mutw].
7357 * [A stable regression in `VecDeque::push_back` and other
7358   capacity-altering methods that caused panics for zero-sized types
7359   was fixed][vd].
7360 * [Function pointers implement traits for up to 12 parameters][fp2].
7361
7362 Miscellaneous
7363 -------------
7364
7365 * The compiler [no longer uses the 'morestack' feature to prevent
7366   stack overflow][mm]. Instead it uses guard pages and stack
7367   probes (though stack probes are not yet implemented on any platform
7368   but Windows).
7369 * [The compiler matches traits faster when projections are involved][p].
7370 * The 'improper_ctypes' lint [no longer warns about use of `isize` and
7371   `usize`][ffi].
7372 * [Cargo now displays useful information about what its doing during
7373   `cargo update`][cu].
7374
7375 [`Arc::downgrade`]: http://doc.rust-lang.org/nightly/alloc/arc/struct.Arc.html#method.downgrade
7376 [`Arc::make_mut`]: http://doc.rust-lang.org/nightly/alloc/arc/struct.Arc.html#method.make_mut
7377 [`Arc::get_mut`]: http://doc.rust-lang.org/nightly/alloc/arc/struct.Arc.html#method.get_mut
7378 [`Arc::try_unwrap`]: http://doc.rust-lang.org/nightly/alloc/arc/struct.Arc.html#method.try_unwrap
7379 [`Box::from_raw`]: http://doc.rust-lang.org/nightly/alloc/boxed/struct.Box.html#method.from_raw
7380 [`Box::into_raw`]: http://doc.rust-lang.org/nightly/alloc/boxed/struct.Box.html#method.into_raw
7381 [`CStr::to_str`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CStr.html#method.to_str
7382 [`CStr::to_string_lossy`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CStr.html#method.to_string_lossy
7383 [`CString::from_raw`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CString.html#method.from_raw
7384 [`CString::into_raw`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CString.html#method.into_raw
7385 [`IntoRawFd::into_raw_fd`]: http://doc.rust-lang.org/nightly/std/os/unix/io/trait.IntoRawFd.html#tymethod.into_raw_fd
7386 [`IntoRawFd`]: http://doc.rust-lang.org/nightly/std/os/unix/io/trait.IntoRawFd.html
7387 [`Rc::downgrade`]: http://doc.rust-lang.org/nightly/alloc/rc/struct.Rc.html#method.downgrade
7388 [`Rc::get_mut`]: http://doc.rust-lang.org/nightly/alloc/rc/struct.Rc.html#method.get_mut
7389 [`Rc::make_mut`]: http://doc.rust-lang.org/nightly/alloc/rc/struct.Rc.html#method.make_mut
7390 [`Rc::try_unwrap`]: http://doc.rust-lang.org/nightly/alloc/rc/struct.Rc.html#method.try_unwrap
7391 [`Result::expect`]: http://doc.rust-lang.org/nightly/core/result/enum.Result.html#method.expect
7392 [`String::into_boxed_str`]: http://doc.rust-lang.org/nightly/collections/string/struct.String.html#method.into_boxed_str
7393 [`TcpStream::read_timeout`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.read_timeout
7394 [`TcpStream::set_read_timeout`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_read_timeout
7395 [`TcpStream::write_timeout`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.write_timeout
7396 [`TcpStream::set_write_timeout`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_write_timeout
7397 [`UdpSocket::read_timeout`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.read_timeout
7398 [`UdpSocket::set_read_timeout`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_read_timeout
7399 [`UdpSocket::write_timeout`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.write_timeout
7400 [`UdpSocket::set_write_timeout`]: http://doc.rust-lang.org/nightly/std/net/struct.TcpStream.html#method.set_write_timeout
7401 [`VecDeque::append`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.append
7402 [`VecDeque::retain`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.retain
7403 [`VecDeque::split_off`]: http://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.split_off
7404 [`rc::Weak::upgrade`]: http://doc.rust-lang.org/nightly/std/rc/struct.Weak.html#method.upgrade
7405 [`rc::Weak`]: http://doc.rust-lang.org/nightly/std/rc/struct.Weak.html
7406 [`slice::Iter::as_slice`]: http://doc.rust-lang.org/nightly/std/slice/struct.Iter.html#method.as_slice
7407 [`slice::IterMut::into_slice`]: http://doc.rust-lang.org/nightly/std/slice/struct.IterMut.html#method.into_slice
7408 [`str::CharIndices::as_str`]: http://doc.rust-lang.org/nightly/std/str/struct.CharIndices.html#method.as_str
7409 [`str::Chars::as_str`]: http://doc.rust-lang.org/nightly/std/str/struct.Chars.html#method.as_str
7410 [`str::split_at_mut`]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.split_at_mut
7411 [`str::split_at`]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.split_at
7412 [`sync::Weak::upgrade`]: http://doc.rust-lang.org/nightly/std/sync/struct.Weak.html#method.upgrade
7413 [`sync::Weak`]: http://doc.rust-lang.org/nightly/std/sync/struct.Weak.html
7414 [`thread::park_timeout`]: http://doc.rust-lang.org/nightly/std/thread/fn.park_timeout.html
7415 [`thread::sleep`]: http://doc.rust-lang.org/nightly/std/thread/fn.sleep.html
7416 [bh2]: https://github.com/rust-lang/rust/pull/28156
7417 [binfat]: https://github.com/rust-lang/rust/pull/28270
7418 [bm]: https://github.com/rust-lang/rust/pull/28197
7419 [cc]: https://github.com/rust-lang/rust/pull/27531
7420 [crlf]: https://github.com/rust-lang/rust/pull/28034
7421 [cu]: https://github.com/rust-lang/cargo/pull/1931
7422 [d]: https://github.com/rust-lang/rust/pull/27825
7423 [dep]: https://github.com/rust-lang/rust/pull/28339
7424 [es]: https://github.com/rust-lang/rust/pull/27956
7425 [ext]: https://github.com/rust-lang/rust/pull/28094
7426 [faststr]: https://github.com/rust-lang/rust/pull/28338
7427 [ffi]: https://github.com/rust-lang/rust/pull/28779
7428 [fp]: https://github.com/rust-lang/rust/pull/28268
7429 [fp2]: https://github.com/rust-lang/rust/pull/28560
7430 [fp3]: https://github.com/rust-lang/rust/pull/27307
7431 [i]: https://github.com/rust-lang/rust/pull/27451
7432 [into2]: https://github.com/rust-lang/rust/pull/28039
7433 [it]: https://github.com/rust-lang/rust/pull/27652
7434 [mm]: https://github.com/rust-lang/rust/pull/27338
7435 [mutw]: https://github.com/rust-lang/rust/pull/28368
7436 [sound]: https://github.com/rust-lang/rust/pull/27641
7437 [p]: https://github.com/rust-lang/rust/pull/27866
7438 [pec]: https://github.com/rust-lang/rust/pull/28486
7439 [pr]: https://github.com/rust-lang/rust/pull/27896
7440 [RFC 839]: https://github.com/rust-lang/rfcs/blob/master/text/0839-embrace-extend-extinguish.md
7441 [RFC 1214]: https://github.com/rust-lang/rfcs/blob/master/text/1214-projections-lifetimes-and-wf.md
7442 [s]: https://github.com/rust-lang/rust/pull/27474
7443 [stab]: https://github.com/rust-lang/rust/pull/28339
7444 [stat]: https://github.com/rust-lang/rust/pull/28321
7445 [vd]: https://github.com/rust-lang/rust/pull/28494
7446
7447 Version 1.3.0 (2015-09-17)
7448 ==============================
7449
7450 * ~900 changes, numerous bugfixes
7451
7452 Highlights
7453 ----------
7454
7455 * The [new object lifetime defaults][nold] have been [turned
7456   on][nold2] after a cycle of warnings about the change. Now types
7457   like `&'a Box<Trait>` (or `&'a Rc<Trait>`, etc) will change from
7458   being interpreted as `&'a Box<Trait+'a>` to `&'a
7459   Box<Trait+'static>`.
7460 * [The Rustonomicon][nom] is a new book in the official documentation
7461   that dives into writing unsafe Rust.
7462 * The [`Duration`] API, [has been stabilized][ds]. This basic unit of
7463   timekeeping is employed by other std APIs, as well as out-of-tree
7464   time crates.
7465
7466 Breaking Changes
7467 ----------------
7468
7469 * The [new object lifetime defaults][nold] have been [turned
7470   on][nold2] after a cycle of warnings about the change.
7471 * There is a known [regression][lr] in how object lifetime elision is
7472   interpreted, the proper solution for which is undetermined.
7473 * The `#[prelude_import]` attribute, an internal implementation
7474   detail, was accidentally stabilized previously. [It has been put
7475   behind the `prelude_import` feature gate][pi]. This change is
7476   believed to break no existing code.
7477 * The behavior of [`size_of_val`][dst1] and [`align_of_val`][dst2] is
7478   [more sane for dynamically sized types][dst3]. Code that relied on
7479   the previous behavior is thought to be broken.
7480 * The `dropck` rules, which checks that destructors can't access
7481   destroyed values, [have been updated][dropck] to match the
7482   [RFC][dropckrfc]. This fixes some soundness holes, and as such will
7483   cause some previously-compiling code to no longer build.
7484
7485 Language
7486 --------
7487
7488 * The [new object lifetime defaults][nold] have been [turned
7489   on][nold2] after a cycle of warnings about the change.
7490 * Semicolons may [now follow types and paths in
7491   macros](https://github.com/rust-lang/rust/pull/27000).
7492 * The behavior of [`size_of_val`][dst1] and [`align_of_val`][dst2] is
7493   [more sane for dynamically sized types][dst3]. Code that relied on
7494   the previous behavior is not known to exist, and suspected to be
7495   broken.
7496 * `'static` variables [may now be recursive][st].
7497 * `ref` bindings choose between [`Deref`] and [`DerefMut`]
7498   implementations correctly.
7499 * The `dropck` rules, which checks that destructors can't access
7500   destroyed values, [have been updated][dropck] to match the
7501   [RFC][dropckrfc].
7502
7503 Libraries
7504 ---------
7505
7506 * The [`Duration`] API, [has been stabilized][ds], as well as the
7507   `std::time` module, which presently contains only `Duration`.
7508 * `Box<str>` and `Box<[T]>` both implement `Clone`.
7509 * The owned C string, [`CString`], implements [`Borrow`] and the
7510   borrowed C string, [`CStr`], implements [`ToOwned`]. The two of
7511   these allow C strings to be borrowed and cloned in generic code.
7512 * [`CStr`] implements [`Debug`].
7513 * [`AtomicPtr`] implements [`Debug`].
7514 * [`Error`] trait objects [can be downcast to their concrete types][e]
7515   in many common configurations, using the [`is`], [`downcast`],
7516   [`downcast_ref`] and [`downcast_mut`] methods, similarly to the
7517   [`Any`] trait.
7518 * Searching for substrings now [employs the two-way algorithm][search]
7519   instead of doing a naive search. This gives major speedups to a
7520   number of methods, including [`contains`][sc], [`find`][sf],
7521   [`rfind`][srf], [`split`][ss]. [`starts_with`][ssw] and
7522   [`ends_with`][sew] are also faster.
7523 * The performance of `PartialEq` for slices is [much faster][ps].
7524 * The [`Hash`] trait offers the default method, [`hash_slice`], which
7525   is overridden and optimized by the implementations for scalars.
7526 * The [`Hasher`] trait now has a number of specialized `write_*`
7527   methods for primitive types, for efficiency.
7528 * The I/O-specific error type, [`std::io::Error`][ie], gained a set of
7529   methods for accessing the 'inner error', if any: [`get_ref`][iegr],
7530   [`get_mut`][iegm], [`into_inner`][ieii]. As well, the implementation
7531   of [`std::error::Error::cause`][iec] also delegates to the inner
7532   error.
7533 * [`process::Child`][pc] gained the [`id`] method, which returns a
7534   `u32` representing the platform-specific process identifier.
7535 * The [`connect`] method on slices is deprecated, replaced by the new
7536   [`join`] method (note that both of these are on the *unstable*
7537   [`SliceConcatExt`] trait, but through the magic of the prelude are
7538   available to stable code anyway).
7539 * The [`Div`] operator is implemented for [`Wrapping`] types.
7540 * [`DerefMut` is implemented for `String`][dms].
7541 * Performance of SipHash (the default hasher for `HashMap`) is
7542   [better for long data][sh].
7543 * [`AtomicPtr`] implements [`Send`].
7544 * The [`read_to_end`] implementations for [`Stdin`] and [`File`]
7545   are now [specialized to use uninitialized buffers for increased
7546   performance][rte].
7547 * Lifetime parameters of foreign functions [are now resolved
7548   properly][f].
7549
7550 Misc
7551 ----
7552
7553 * Rust can now, with some coercion, [produce programs that run on
7554   Windows XP][xp], though XP is not considered a supported platform.
7555 * Porting Rust on Windows from the GNU toolchain to MSVC continues
7556   ([1][win1], [2][win2], [3][win3], [4][win4]). It is still not
7557   recommended for use in 1.3, though should be fully-functional
7558   in the [64-bit 1.4 beta][b14].
7559 * On Fedora-based systems installation will [properly configure the
7560   dynamic linker][fl].
7561 * The compiler gained many new extended error descriptions, which can
7562   be accessed with the `--explain` flag.
7563 * The `dropck` pass, which checks that destructors can't access
7564   destroyed values, [has been rewritten][dropck]. This fixes some
7565   soundness holes, and as such will cause some previously-compiling
7566   code to no longer build.
7567 * `rustc` now uses [LLVM to write archive files where possible][ar].
7568   Eventually this will eliminate the compiler's dependency on the ar
7569   utility.
7570 * Rust has [preliminary support for i686 FreeBSD][fb] (it has long
7571   supported FreeBSD on x86_64).
7572 * The [`unused_mut`][lum], [`unconditional_recursion`][lur],
7573   [`improper_ctypes`][lic], and [`negate_unsigned`][lnu] lints are
7574   more strict.
7575 * If landing pads are disabled (with `-Z no-landing-pads`), [`panic!`
7576   will kill the process instead of leaking][nlp].
7577
7578 [`Any`]: http://doc.rust-lang.org/nightly/std/any/trait.Any.html
7579 [`AtomicPtr`]: http://doc.rust-lang.org/nightly/std/sync/atomic/struct.AtomicPtr.html
7580 [`Borrow`]: http://doc.rust-lang.org/nightly/std/borrow/trait.Borrow.html
7581 [`CStr`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CStr.html
7582 [`CString`]: http://doc.rust-lang.org/nightly/std/ffi/struct.CString.html
7583 [`Debug`]: http://doc.rust-lang.org/nightly/std/fmt/trait.Debug.html
7584 [`DerefMut`]: http://doc.rust-lang.org/nightly/std/ops/trait.DerefMut.html
7585 [`Deref`]: http://doc.rust-lang.org/nightly/std/ops/trait.Deref.html
7586 [`Div`]: http://doc.rust-lang.org/nightly/std/ops/trait.Div.html
7587 [`Duration`]: http://doc.rust-lang.org/nightly/std/time/struct.Duration.html
7588 [`Error`]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html
7589 [`File`]: http://doc.rust-lang.org/nightly/std/fs/struct.File.html
7590 [`Hash`]: http://doc.rust-lang.org/nightly/std/hash/trait.Hash.html
7591 [`Hasher`]: http://doc.rust-lang.org/nightly/std/hash/trait.Hasher.html
7592 [`Send`]: http://doc.rust-lang.org/nightly/std/marker/trait.Send.html
7593 [`SliceConcatExt`]: http://doc.rust-lang.org/nightly/std/slice/trait.SliceConcatExt.html
7594 [`Stdin`]: http://doc.rust-lang.org/nightly/std/io/struct.Stdin.html
7595 [`ToOwned`]: http://doc.rust-lang.org/nightly/std/borrow/trait.ToOwned.html
7596 [`Wrapping`]: http://doc.rust-lang.org/nightly/std/num/struct.Wrapping.html
7597 [`connect`]: http://doc.rust-lang.org/nightly/std/slice/trait.SliceConcatExt.html#method.connect
7598 [`downcast_mut`]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html#method.downcast_mut
7599 [`downcast_ref`]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html#method.downcast_ref
7600 [`downcast`]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html#method.downcast
7601 [`hash_slice`]: http://doc.rust-lang.org/nightly/std/hash/trait.Hash.html#method.hash_slice
7602 [`id`]: http://doc.rust-lang.org/nightly/std/process/struct.Child.html#method.id
7603 [`is`]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html#method.is
7604 [`join`]: http://doc.rust-lang.org/nightly/std/slice/trait.SliceConcatExt.html#method.join
7605 [`read_to_end`]: http://doc.rust-lang.org/nightly/std/io/trait.Read.html#method.read_to_end
7606 [ar]: https://github.com/rust-lang/rust/pull/26926
7607 [b14]: https://static.rust-lang.org/dist/rust-beta-x86_64-pc-windows-msvc.msi
7608 [dms]: https://github.com/rust-lang/rust/pull/26241
7609 [dropck]: https://github.com/rust-lang/rust/pull/27261
7610 [dropckrfc]: https://github.com/rust-lang/rfcs/blob/master/text/0769-sound-generic-drop.md
7611 [ds]: https://github.com/rust-lang/rust/pull/26818
7612 [dst1]: http://doc.rust-lang.org/nightly/std/mem/fn.size_of_val.html
7613 [dst2]: http://doc.rust-lang.org/nightly/std/mem/fn.align_of_val.html
7614 [dst3]: https://github.com/rust-lang/rust/pull/27351
7615 [e]: https://github.com/rust-lang/rust/pull/24793
7616 [f]: https://github.com/rust-lang/rust/pull/26588
7617 [fb]: https://github.com/rust-lang/rust/pull/26959
7618 [fl]: https://github.com/rust-lang/rust-installer/pull/41
7619 [hs]: http://doc.rust-lang.org/nightly/std/hash/trait.Hash.html#method.hash_slice
7620 [ie]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html
7621 [iec]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html#method.cause
7622 [iegm]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html#method.get_mut
7623 [iegr]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html#method.get_ref
7624 [ieii]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html#method.into_inner
7625 [lic]: https://github.com/rust-lang/rust/pull/26583
7626 [lnu]: https://github.com/rust-lang/rust/pull/27026
7627 [lr]: https://github.com/rust-lang/rust/issues/27248
7628 [lum]: https://github.com/rust-lang/rust/pull/26378
7629 [lur]: https://github.com/rust-lang/rust/pull/26783
7630 [nlp]: https://github.com/rust-lang/rust/pull/27176
7631 [nold2]: https://github.com/rust-lang/rust/pull/27045
7632 [nold]: https://github.com/rust-lang/rfcs/blob/master/text/1156-adjust-default-object-bounds.md
7633 [nom]: http://doc.rust-lang.org/nightly/nomicon/
7634 [pc]: http://doc.rust-lang.org/nightly/std/process/struct.Child.html
7635 [pi]: https://github.com/rust-lang/rust/pull/26699
7636 [ps]: https://github.com/rust-lang/rust/pull/26884
7637 [rte]: https://github.com/rust-lang/rust/pull/26950
7638 [sc]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.contains
7639 [search]: https://github.com/rust-lang/rust/pull/26327
7640 [sew]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.ends_with
7641 [sf]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.find
7642 [sh]: https://github.com/rust-lang/rust/pull/27280
7643 [srf]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.rfind
7644 [ss]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.split
7645 [ssw]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.starts_with
7646 [st]: https://github.com/rust-lang/rust/pull/26630
7647 [win1]: https://github.com/rust-lang/rust/pull/26569
7648 [win2]: https://github.com/rust-lang/rust/pull/26741
7649 [win3]: https://github.com/rust-lang/rust/pull/26741
7650 [win4]: https://github.com/rust-lang/rust/pull/27210
7651 [xp]: https://github.com/rust-lang/rust/pull/26569
7652
7653 Version 1.2.0 (2015-08-07)
7654 ==========================
7655
7656 * ~1200 changes, numerous bugfixes
7657
7658 Highlights
7659 ----------
7660
7661 * [Dynamically-sized-type coercions][dst] allow smart pointer types
7662   like `Rc` to contain types without a fixed size, arrays and trait
7663   objects, finally enabling use of `Rc<[T]>` and completing the
7664   implementation of DST.
7665 * [Parallel codegen][parcodegen] is now working again, which can
7666   substantially speed up large builds in debug mode; It also gets
7667   another ~33% speedup when bootstrapping on a 4 core machine (using 8
7668   jobs). It's not enabled by default, but will be "in the near
7669   future". It can be activated with the `-C codegen-units=N` flag to
7670   `rustc`.
7671 * This is the first release with [experimental support for linking
7672   with the MSVC linker and lib C on Windows (instead of using the GNU
7673   variants via MinGW)][win]. It is yet recommended only for the most
7674   intrepid Rustaceans.
7675 * Benchmark compilations are showing a 30% improvement in
7676   bootstrapping over 1.1.
7677
7678 Breaking Changes
7679 ----------------
7680
7681 * The [`to_uppercase`] and [`to_lowercase`] methods on `char` now do
7682   unicode case mapping, which is a previously-planned change in
7683   behavior and considered a bugfix.
7684 * [`mem::align_of`] now specifies [the *minimum alignment* for
7685   T][align], which is usually the alignment programs are interested
7686   in, and the same value reported by clang's
7687   `alignof`. [`mem::min_align_of`] is deprecated. This is not known to
7688   break real code.
7689 * [The `#[packed]` attribute is no longer silently accepted by the
7690   compiler][packed]. This attribute did nothing and code that
7691   mentioned it likely did not work as intended.
7692 * Associated type defaults are [now behind the
7693   `associated_type_defaults` feature gate][ad]. In 1.1 associated type
7694   defaults *did not work*, but could be mentioned syntactically. As
7695   such this breakage has minimal impact.
7696
7697 Language
7698 --------
7699
7700 * Patterns with `ref mut` now correctly invoke [`DerefMut`] when
7701   matching against dereferenceable values.
7702
7703 Libraries
7704 ---------
7705
7706 * The [`Extend`] trait, which grows a collection from an iterator, is
7707   implemented over iterators of references, for `String`, `Vec`,
7708   `LinkedList`, `VecDeque`, `EnumSet`, `BinaryHeap`, `VecMap`,
7709   `BTreeSet` and `BTreeMap`. [RFC][extend-rfc].
7710 * The [`iter::once`] function returns an iterator that yields a single
7711   element, and [`iter::empty`] returns an iterator that yields no
7712   elements.
7713 * The [`matches`] and [`rmatches`] methods on `str` return iterators
7714   over substring matches.
7715 * [`Cell`] and [`RefCell`] both implement `Eq`.
7716 * A number of methods for wrapping arithmetic are added to the
7717   integral types, [`wrapping_div`], [`wrapping_rem`],
7718   [`wrapping_neg`], [`wrapping_shl`], [`wrapping_shr`]. These are in
7719   addition to the existing [`wrapping_add`], [`wrapping_sub`], and
7720   [`wrapping_mul`] methods, and alternatives to the [`Wrapping`]
7721   type.. It is illegal for the default arithmetic operations in Rust
7722   to overflow; the desire to wrap must be explicit.
7723 * The `{:#?}` formatting specifier [displays the alternate,
7724   pretty-printed][debugfmt] form of the `Debug` formatter. This
7725   feature was actually introduced prior to 1.0 with little
7726   fanfare.
7727 * [`fmt::Formatter`] implements [`fmt::Write`], a `fmt`-specific trait
7728   for writing data to formatted strings, similar to [`io::Write`].
7729 * [`fmt::Formatter`] adds 'debug builder' methods, [`debug_struct`],
7730   [`debug_tuple`], [`debug_list`], [`debug_set`], [`debug_map`]. These
7731   are used by code generators to emit implementations of [`Debug`].
7732 * `str` has new [`to_uppercase`][strup] and [`to_lowercase`][strlow]
7733   methods that convert case, following Unicode case mapping.
7734 * It is now easier to handle poisoned locks. The [`PoisonError`]
7735   type, returned by failing lock operations, exposes `into_inner`,
7736   `get_ref`, and `get_mut`, which all give access to the inner lock
7737   guard, and allow the poisoned lock to continue to operate. The
7738   `is_poisoned` method of [`RwLock`] and [`Mutex`] can poll for a
7739   poisoned lock without attempting to take the lock.
7740 * On Unix the [`FromRawFd`] trait is implemented for [`Stdio`], and
7741   [`AsRawFd`] for [`ChildStdin`], [`ChildStdout`], [`ChildStderr`].
7742   On Windows the `FromRawHandle` trait is implemented for `Stdio`,
7743   and `AsRawHandle` for `ChildStdin`, `ChildStdout`,
7744   `ChildStderr`.
7745 * [`io::ErrorKind`] has a new variant, `InvalidData`, which indicates
7746   malformed input.
7747
7748 Misc
7749 ----
7750
7751 * `rustc` employs smarter heuristics for guessing at [typos].
7752 * `rustc` emits more efficient code for [no-op conversions between
7753   unsafe pointers][nop].
7754 * Fat pointers are now [passed in pairs of immediate arguments][fat],
7755   resulting in faster compile times and smaller code.
7756
7757 [`Extend`]: https://doc.rust-lang.org/nightly/std/iter/trait.Extend.html
7758 [extend-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0839-embrace-extend-extinguish.md
7759 [`iter::once`]: https://doc.rust-lang.org/nightly/std/iter/fn.once.html
7760 [`iter::empty`]: https://doc.rust-lang.org/nightly/std/iter/fn.empty.html
7761 [`matches`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.matches
7762 [`rmatches`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.rmatches
7763 [`Cell`]: https://doc.rust-lang.org/nightly/std/cell/struct.Cell.html
7764 [`RefCell`]: https://doc.rust-lang.org/nightly/std/cell/struct.RefCell.html
7765 [`wrapping_add`]: https://doc.rust-lang.org/nightly/std/primitive.i8.html#method.wrapping_add
7766 [`wrapping_sub`]: https://doc.rust-lang.org/nightly/std/primitive.i8.html#method.wrapping_sub
7767 [`wrapping_mul`]: https://doc.rust-lang.org/nightly/std/primitive.i8.html#method.wrapping_mul
7768 [`wrapping_div`]: https://doc.rust-lang.org/nightly/std/primitive.i8.html#method.wrapping_div
7769 [`wrapping_rem`]: https://doc.rust-lang.org/nightly/std/primitive.i8.html#method.wrapping_rem
7770 [`wrapping_neg`]: https://doc.rust-lang.org/nightly/std/primitive.i8.html#method.wrapping_neg
7771 [`wrapping_shl`]: https://doc.rust-lang.org/nightly/std/primitive.i8.html#method.wrapping_shl
7772 [`wrapping_shr`]: https://doc.rust-lang.org/nightly/std/primitive.i8.html#method.wrapping_shr
7773 [`Wrapping`]: https://doc.rust-lang.org/nightly/std/num/struct.Wrapping.html
7774 [`fmt::Formatter`]: https://doc.rust-lang.org/nightly/std/fmt/struct.Formatter.html
7775 [`fmt::Write`]: https://doc.rust-lang.org/nightly/std/fmt/trait.Write.html
7776 [`io::Write`]: https://doc.rust-lang.org/nightly/std/io/trait.Write.html
7777 [`debug_struct`]: https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.debug_struct
7778 [`debug_tuple`]: https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.debug_tuple
7779 [`debug_list`]: https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.debug_list
7780 [`debug_set`]: https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.debug_set
7781 [`debug_map`]: https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html#method.debug_map
7782 [`Debug`]: https://doc.rust-lang.org/nightly/std/fmt/trait.Debug.html
7783 [strup]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.to_uppercase
7784 [strlow]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.to_lowercase
7785 [`to_uppercase`]: https://doc.rust-lang.org/nightly/std/primitive.char.html#method.to_uppercase
7786 [`to_lowercase`]: https://doc.rust-lang.org/nightly/std/primitive.char.html#method.to_lowercase
7787 [`PoisonError`]: https://doc.rust-lang.org/nightly/std/sync/struct.PoisonError.html
7788 [`RwLock`]: https://doc.rust-lang.org/nightly/std/sync/struct.RwLock.html
7789 [`Mutex`]: https://doc.rust-lang.org/nightly/std/sync/struct.Mutex.html
7790 [`FromRawFd`]: https://doc.rust-lang.org/nightly/std/os/unix/io/trait.FromRawFd.html
7791 [`AsRawFd`]: https://doc.rust-lang.org/nightly/std/os/unix/io/trait.AsRawFd.html
7792 [`Stdio`]: https://doc.rust-lang.org/nightly/std/process/struct.Stdio.html
7793 [`ChildStdin`]: https://doc.rust-lang.org/nightly/std/process/struct.ChildStdin.html
7794 [`ChildStdout`]: https://doc.rust-lang.org/nightly/std/process/struct.ChildStdout.html
7795 [`ChildStderr`]: https://doc.rust-lang.org/nightly/std/process/struct.ChildStderr.html
7796 [`io::ErrorKind`]: https://doc.rust-lang.org/nightly/std/io/enum.ErrorKind.html
7797 [debugfmt]: https://www.reddit.com/r/rust/comments/3ceaui/psa_produces_prettyprinted_debug_output/
7798 [`DerefMut`]: https://doc.rust-lang.org/nightly/std/ops/trait.DerefMut.html
7799 [`mem::align_of`]: https://doc.rust-lang.org/nightly/std/mem/fn.align_of.html
7800 [align]: https://github.com/rust-lang/rust/pull/25646
7801 [`mem::min_align_of`]: https://doc.rust-lang.org/nightly/std/mem/fn.min_align_of.html
7802 [typos]: https://github.com/rust-lang/rust/pull/26087
7803 [nop]: https://github.com/rust-lang/rust/pull/26336
7804 [fat]: https://github.com/rust-lang/rust/pull/26411
7805 [dst]: https://github.com/rust-lang/rfcs/blob/master/text/0982-dst-coercion.md
7806 [parcodegen]: https://github.com/rust-lang/rust/pull/26018
7807 [packed]: https://github.com/rust-lang/rust/pull/25541
7808 [ad]: https://github.com/rust-lang/rust/pull/27382
7809 [win]: https://github.com/rust-lang/rust/pull/25350
7810
7811 Version 1.1.0 (2015-06-25)
7812 =========================
7813
7814 * ~850 changes, numerous bugfixes
7815
7816 Highlights
7817 ----------
7818
7819 * The [`std::fs` module has been expanded][fs] to expand the set of
7820   functionality exposed:
7821   * `DirEntry` now supports optimizations like `file_type` and `metadata` which
7822     don't incur a syscall on some platforms.
7823   * A `symlink_metadata` function has been added.
7824   * The `fs::Metadata` structure now lowers to its OS counterpart, providing
7825     access to all underlying information.
7826 * The compiler now contains extended explanations of many errors. When an error
7827   with an explanation occurs the compiler suggests using the `--explain` flag
7828   to read the explanation. Error explanations are also [available online][err-index].
7829 * Thanks to multiple [improvements][sk] to [type checking][pre], as
7830   well as other work, the time to bootstrap the compiler decreased by
7831   32%.
7832
7833 Libraries
7834 ---------
7835
7836 * The [`str::split_whitespace`] method splits a string on unicode
7837   whitespace boundaries.
7838 * On both Windows and Unix, new extension traits provide conversion of
7839   I/O types to and from the underlying system handles. On Unix, these
7840   traits are [`FromRawFd`] and [`AsRawFd`], on Windows `FromRawHandle`
7841   and `AsRawHandle`. These are implemented for `File`, `TcpStream`,
7842   `TcpListener`, and `UpdSocket`. Further implementations for
7843   `std::process` will be stabilized later.
7844 * On Unix, [`std::os::unix::symlink`] creates symlinks. On
7845   Windows, symlinks can be created with
7846   `std::os::windows::symlink_dir` and
7847   `std::os::windows::symlink_file`.
7848 * The `mpsc::Receiver` type can now be converted into an iterator with
7849   `into_iter` on the [`IntoIterator`] trait.
7850 * `Ipv4Addr` can be created from `u32` with the `From<u32>`
7851   implementation of the [`From`] trait.
7852 * The `Debug` implementation for `RangeFull` [creates output that is
7853   more consistent with other implementations][rf].
7854 * [`Debug` is implemented for `File`][file].
7855 * The `Default` implementation for `Arc` [no longer requires `Sync +
7856   Send`][arc].
7857 * [The `Iterator` methods `count`, `nth`, and `last` have been
7858   overridden for slices to have O(1) performance instead of O(n)][si].
7859 * Incorrect handling of paths on Windows has been improved in both the
7860   compiler and the standard library.
7861 * [`AtomicPtr` gained a `Default` implementation][ap].
7862 * In accordance with Rust's policy on arithmetic overflow `abs` now
7863   [panics on overflow when debug assertions are enabled][abs].
7864 * The [`Cloned`] iterator, which was accidentally left unstable for
7865   1.0 [has been stabilized][c].
7866 * The [`Incoming`] iterator, which iterates over incoming TCP
7867   connections, and which was accidentally unnamable in 1.0, [is now
7868   properly exported][inc].
7869 * [`BinaryHeap`] no longer corrupts itself [when functions called by
7870   `sift_up` or `sift_down` panic][bh].
7871 * The [`split_off`] method of `LinkedList` [no longer corrupts
7872   the list in certain scenarios][ll].
7873
7874 Misc
7875 ----
7876
7877 * Type checking performance [has improved notably][sk] with
7878   [multiple improvements][pre].
7879 * The compiler [suggests code changes][ch] for more errors.
7880 * rustc and it's build system have experimental support for [building
7881   toolchains against MUSL][m] instead of glibc on Linux.
7882 * The compiler defines the `target_env` cfg value, which is used for
7883   distinguishing toolchains that are otherwise for the same
7884   platform. Presently this is set to `gnu` for common GNU Linux
7885   targets and for MinGW targets, and `musl` for MUSL Linux targets.
7886 * The [`cargo rustc`][crc] command invokes a build with custom flags
7887   to rustc.
7888 * [Android executables are always position independent][pie].
7889 * [The `drop_with_repr_extern` lint warns about mixing `repr(C)`
7890   with `Drop`][drop].
7891
7892 [`str::split_whitespace`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.split_whitespace
7893 [`FromRawFd`]: https://doc.rust-lang.org/nightly/std/os/unix/io/trait.FromRawFd.html
7894 [`AsRawFd`]: https://doc.rust-lang.org/nightly/std/os/unix/io/trait.AsRawFd.html
7895 [`std::os::unix::symlink`]: https://doc.rust-lang.org/nightly/std/os/unix/fs/fn.symlink.html
7896 [`IntoIterator`]: https://doc.rust-lang.org/nightly/std/iter/trait.IntoIterator.html
7897 [`From`]: https://doc.rust-lang.org/nightly/std/convert/trait.From.html
7898 [rf]: https://github.com/rust-lang/rust/pull/24491
7899 [err-index]: https://doc.rust-lang.org/error-index.html
7900 [sk]: https://github.com/rust-lang/rust/pull/24615
7901 [pre]: https://github.com/rust-lang/rust/pull/25323
7902 [file]: https://github.com/rust-lang/rust/pull/24598
7903 [ch]: https://github.com/rust-lang/rust/pull/24683
7904 [arc]: https://github.com/rust-lang/rust/pull/24695
7905 [si]: https://github.com/rust-lang/rust/pull/24701
7906 [ap]: https://github.com/rust-lang/rust/pull/24834
7907 [m]: https://github.com/rust-lang/rust/pull/24777
7908 [fs]: https://github.com/rust-lang/rfcs/blob/master/text/1044-io-fs-2.1.md
7909 [crc]: https://github.com/rust-lang/cargo/pull/1568
7910 [pie]: https://github.com/rust-lang/rust/pull/24953
7911 [abs]: https://github.com/rust-lang/rust/pull/25441
7912 [c]: https://github.com/rust-lang/rust/pull/25496
7913 [`Cloned`]: https://doc.rust-lang.org/nightly/std/iter/struct.Cloned.html
7914 [`Incoming`]: https://doc.rust-lang.org/nightly/std/net/struct.Incoming.html
7915 [inc]: https://github.com/rust-lang/rust/pull/25522
7916 [bh]: https://github.com/rust-lang/rust/pull/25856
7917 [`BinaryHeap`]: https://doc.rust-lang.org/nightly/std/collections/struct.BinaryHeap.html
7918 [ll]: https://github.com/rust-lang/rust/pull/26022
7919 [`split_off`]: https://doc.rust-lang.org/nightly/collections/linked_list/struct.LinkedList.html#method.split_off
7920 [drop]: https://github.com/rust-lang/rust/pull/24935
7921
7922 Version 1.0.0 (2015-05-15)
7923 ========================
7924
7925 * ~1500 changes, numerous bugfixes
7926
7927 Highlights
7928 ----------
7929
7930 * The vast majority of the standard library is now `#[stable]`. It is
7931   no longer possible to use unstable features with a stable build of
7932   the compiler.
7933 * Many popular crates on [crates.io] now work on the stable release
7934   channel.
7935 * Arithmetic on basic integer types now [checks for overflow in debug
7936   builds][overflow].
7937
7938 Language
7939 --------
7940
7941 * Several [restrictions have been added to trait coherence][coh] in
7942   order to make it easier for upstream authors to change traits
7943   without breaking downstream code.
7944 * Digits of binary and octal literals are [lexed more eagerly][lex] to
7945   improve error messages and macro behavior. For example, `0b1234` is
7946   now lexed as `0b1234` instead of two tokens, `0b1` and `234`.
7947 * Trait bounds [are always invariant][inv], eliminating the need for
7948   the `PhantomFn` and `MarkerTrait` lang items, which have been
7949   removed.
7950 * ["-" is no longer a valid character in crate names][cr], the `extern crate
7951   "foo" as bar` syntax has been replaced with `extern crate foo as
7952   bar`, and Cargo now automatically translates "-" in *package* names
7953   to underscore for the crate name.
7954 * [Lifetime shadowing is an error][lt].
7955 * [`Send` no longer implies `'static`][send-rfc].
7956 * [UFCS now supports trait-less associated paths][moar-ufcs] like
7957   `MyType::default()`.
7958 * Primitive types [now have inherent methods][prim-inherent],
7959   obviating the need for extension traits like `SliceExt`.
7960 * Methods with `Self: Sized` in their `where` clause are [considered
7961   object-safe][self-sized], allowing many extension traits like
7962   `IteratorExt` to be merged into the traits they extended.
7963 * You can now [refer to associated types][assoc-where] whose
7964   corresponding trait bounds appear only in a `where` clause.
7965 * The final bits of [OIBIT landed][oibit-final], meaning that traits
7966   like `Send` and `Sync` are now library-defined.
7967 * A [Reflect trait][reflect] was introduced, which means that
7968   downcasting via the `Any` trait is effectively limited to concrete
7969   types. This helps retain the potentially-important "parametricity"
7970   property: generic code cannot behave differently for different type
7971   arguments except in minor ways.
7972 * The `unsafe_destructor` feature is now deprecated in favor of the
7973   [new `dropck`][dropck]. This change is a major reduction in unsafe
7974   code.
7975
7976 Libraries
7977 ---------
7978
7979 * The `thread_local` module [has been renamed to `std::thread`][th].
7980 * The methods of `IteratorExt` [have been moved to the `Iterator`
7981   trait itself][ie].
7982 * Several traits that implement Rust's conventions for type
7983   conversions, `AsMut`, `AsRef`, `From`, and `Into` have been
7984   [centralized in the `std::convert` module][con].
7985 * The `FromError` trait [was removed in favor of `From`][fe].
7986 * The basic sleep function [has moved to
7987   `std::thread::sleep_ms`][slp].
7988 * The `splitn` function now takes an `n` parameter that represents the
7989   number of items yielded by the returned iterator [instead of the
7990   number of 'splits'][spl].
7991 * [On Unix, all file descriptors are `CLOEXEC` by default][clo].
7992 * [Derived implementations of `PartialOrd` now order enums according
7993   to their explicitly-assigned discriminants][po].
7994 * [Methods for searching strings are generic over `Pattern`s][pat],
7995   implemented presently by `&char`, `&str`, `FnMut(char) -> bool` and
7996   some others.
7997 * [In method resolution, object methods are resolved before inherent
7998   methods][meth].
7999 * [`String::from_str` has been deprecated in favor of the `From` impl,
8000   `String::from`][sf].
8001 * [`io::Error` implements `Sync`][ios].
8002 * [The `words` method on `&str` has been replaced with
8003   `split_whitespace`][sw], to avoid answering the tricky question, 'what is
8004   a word?'
8005 * The new path and IO modules are complete and `#[stable]`. This
8006   was the major library focus for this cycle.
8007 * The path API was [revised][path-normalize] to normalize `.`,
8008   adjusting the tradeoffs in favor of the most common usage.
8009 * A large number of remaining APIs in `std` were also stabilized
8010   during this cycle; about 75% of the non-deprecated API surface
8011   is now stable.
8012 * The new [string pattern API][string-pattern] landed, which makes
8013   the string slice API much more internally consistent and flexible.
8014 * A new set of [generic conversion traits][conversion] replaced
8015   many existing ad hoc traits.
8016 * Generic numeric traits were [completely removed][num-traits]. This
8017   was made possible thanks to inherent methods for primitive types,
8018   and the removal gives maximal flexibility for designing a numeric
8019   hierarchy in the future.
8020 * The `Fn` traits are now related via [inheritance][fn-inherit]
8021   and provide ergonomic [blanket implementations][fn-blanket].
8022 * The `Index` and `IndexMut` traits were changed to
8023   [take the index by value][index-value], enabling code like
8024   `hash_map["string"]` to work.
8025 * `Copy` now [inherits][copy-clone] from `Clone`, meaning that all
8026   `Copy` data is known to be `Clone` as well.
8027
8028 Misc
8029 ----
8030
8031 * Many errors now have extended explanations that can be accessed with
8032   the `--explain` flag to `rustc`.
8033 * Many new examples have been added to the standard library
8034   documentation.
8035 * rustdoc has received a number of improvements focused on completion
8036   and polish.
8037 * Metadata was tuned, shrinking binaries [by 27%][metadata-shrink].
8038 * Much headway was made on ecosystem-wide CI, making it possible
8039   to [compare builds for breakage][ci-compare].
8040
8041
8042 [crates.io]: http://crates.io
8043 [clo]: https://github.com/rust-lang/rust/pull/24034
8044 [coh]: https://github.com/rust-lang/rfcs/blob/master/text/1023-rebalancing-coherence.md
8045 [con]: https://github.com/rust-lang/rust/pull/23875
8046 [cr]: https://github.com/rust-lang/rust/pull/23419
8047 [fe]: https://github.com/rust-lang/rust/pull/23879
8048 [ie]: https://github.com/rust-lang/rust/pull/23300
8049 [inv]: https://github.com/rust-lang/rust/pull/23938
8050 [ios]: https://github.com/rust-lang/rust/pull/24133
8051 [lex]: https://github.com/rust-lang/rfcs/blob/master/text/0879-small-base-lexing.md
8052 [lt]: https://github.com/rust-lang/rust/pull/24057
8053 [meth]: https://github.com/rust-lang/rust/pull/24056
8054 [pat]: https://github.com/rust-lang/rfcs/blob/master/text/0528-string-patterns.md
8055 [po]: https://github.com/rust-lang/rust/pull/24270
8056 [sf]: https://github.com/rust-lang/rust/pull/24517
8057 [slp]: https://github.com/rust-lang/rust/pull/23949
8058 [spl]: https://github.com/rust-lang/rfcs/blob/master/text/0979-align-splitn-with-other-languages.md
8059 [sw]: https://github.com/rust-lang/rfcs/blob/master/text/1054-str-words.md
8060 [th]: https://github.com/rust-lang/rfcs/blob/master/text/0909-move-thread-local-to-std-thread.md
8061 [send-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0458-send-improvements.md
8062 [moar-ufcs]: https://github.com/rust-lang/rust/pull/22172
8063 [prim-inherent]: https://github.com/rust-lang/rust/pull/23104
8064 [overflow]: https://github.com/rust-lang/rfcs/blob/master/text/0560-integer-overflow.md
8065 [metadata-shrink]: https://github.com/rust-lang/rust/pull/22971
8066 [self-sized]: https://github.com/rust-lang/rust/pull/22301
8067 [assoc-where]: https://github.com/rust-lang/rust/pull/22512
8068 [string-pattern]: https://github.com/rust-lang/rust/pull/22466
8069 [oibit-final]: https://github.com/rust-lang/rust/pull/21689
8070 [reflect]: https://github.com/rust-lang/rust/pull/23712
8071 [conversion]: https://github.com/rust-lang/rfcs/pull/529
8072 [num-traits]: https://github.com/rust-lang/rust/pull/23549
8073 [index-value]: https://github.com/rust-lang/rust/pull/23601
8074 [dropck]: https://github.com/rust-lang/rfcs/pull/769
8075 [ci-compare]: https://gist.github.com/brson/a30a77836fbec057cbee
8076 [fn-inherit]: https://github.com/rust-lang/rust/pull/23282
8077 [fn-blanket]: https://github.com/rust-lang/rust/pull/23895
8078 [copy-clone]: https://github.com/rust-lang/rust/pull/23860
8079 [path-normalize]: https://github.com/rust-lang/rust/pull/23229
8080
8081
8082 Version 1.0.0-alpha.2 (2015-02-20)
8083 =====================================
8084
8085 * ~1300 changes, numerous bugfixes
8086
8087 * Highlights
8088
8089     * The various I/O modules were [overhauled][io-rfc] to reduce
8090       unnecessary abstractions and provide better interoperation with
8091       the underlying platform. The old `io` module remains temporarily
8092       at `std::old_io`.
8093     * The standard library now [participates in feature gating][feat],
8094       so use of unstable libraries now requires a `#![feature(...)]`
8095       attribute. The impact of this change is [described on the
8096       forum][feat-forum]. [RFC][feat-rfc].
8097
8098 * Language
8099
8100     * `for` loops [now operate on the `IntoIterator` trait][into],
8101       which eliminates the need to call `.iter()`, etc. to iterate
8102       over collections. There are some new subtleties to remember
8103       though regarding what sort of iterators various types yield, in
8104       particular that `for foo in bar { }` yields values from a move
8105       iterator, destroying the original collection. [RFC][into-rfc].
8106     * Objects now have [default lifetime bounds][obj], so you don't
8107       have to write `Box<Trait+'static>` when you don't care about
8108       storing references. [RFC][obj-rfc].
8109     * In types that implement `Drop`, [lifetimes must outlive the
8110       value][drop]. This will soon make it possible to safely
8111       implement `Drop` for types where `#[unsafe_destructor]` is now
8112       required. Read the [gorgeous RFC][drop-rfc] for details.
8113     * The fully qualified <T as Trait>::X syntax lets you set the Self
8114       type for a trait method or associated type. [RFC][ufcs-rfc].
8115     * References to types that implement `Deref<U>` now [automatically
8116       coerce to references][deref] to the dereferenced type `U`,
8117       e.g. `&T where T: Deref<U>` automatically coerces to `&U`. This
8118       should eliminate many unsightly uses of `&*`, as when converting
8119       from references to vectors into references to
8120       slices. [RFC][deref-rfc].
8121     * The explicit [closure kind syntax][close] (`|&:|`, `|&mut:|`,
8122       `|:|`) is obsolete and closure kind is inferred from context.
8123     * [`Self` is a keyword][Self].
8124
8125 * Libraries
8126
8127     * The `Show` and `String` formatting traits [have been
8128       renamed][fmt] to `Debug` and `Display` to more clearly reflect
8129       their related purposes. Automatically getting a string
8130       conversion to use with `format!("{:?}", something_to_debug)` is
8131       now written `#[derive(Debug)]`.
8132     * Abstract [OS-specific string types][osstr], `std::ff::{OsString,
8133       OsStr}`, provide strings in platform-specific encodings for easier
8134       interop with system APIs. [RFC][osstr-rfc].
8135     * The `boxed::into_raw` and `Box::from_raw` functions [convert
8136       between `Box<T>` and `*mut T`][boxraw], a common pattern for
8137       creating raw pointers.
8138
8139 * Tooling
8140
8141     * Certain long error messages of the form 'expected foo found bar'
8142       are now [split neatly across multiple
8143       lines][multiline]. Examples in the PR.
8144     * On Unix Rust can be [uninstalled][un] by running
8145       `/usr/local/lib/rustlib/uninstall.sh`.
8146     * The `#[rustc_on_unimplemented]` attribute, requiring the
8147       'on_unimplemented' feature, lets rustc [display custom error
8148       messages when a trait is expected to be implemented for a type
8149       but is not][onun].
8150
8151 * Misc
8152
8153     * Rust is tested against a [LALR grammar][lalr], which parses
8154       almost all the Rust files that rustc does.
8155
8156 [boxraw]: https://github.com/rust-lang/rust/pull/21318
8157 [close]: https://github.com/rust-lang/rust/pull/21843
8158 [deref]: https://github.com/rust-lang/rust/pull/21351
8159 [deref-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0241-deref-conversions.md
8160 [drop]: https://github.com/rust-lang/rust/pull/21972
8161 [drop-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0769-sound-generic-drop.md
8162 [feat]: https://github.com/rust-lang/rust/pull/21248
8163 [feat-forum]: https://users.rust-lang.org/t/psa-important-info-about-rustcs-new-feature-staging/82/5
8164 [feat-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0507-release-channels.md
8165 [fmt]: https://github.com/rust-lang/rust/pull/21457
8166 [into]: https://github.com/rust-lang/rust/pull/20790
8167 [into-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0235-collections-conventions.md#intoiterator-and-iterable
8168 [io-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0517-io-os-reform.md
8169 [lalr]: https://github.com/rust-lang/rust/pull/21452
8170 [multiline]: https://github.com/rust-lang/rust/pull/19870
8171 [obj]: https://github.com/rust-lang/rust/pull/22230
8172 [obj-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0599-default-object-bound.md
8173 [onun]: https://github.com/rust-lang/rust/pull/20889
8174 [osstr]: https://github.com/rust-lang/rust/pull/21488
8175 [osstr-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0517-io-os-reform.md
8176 [Self]: https://github.com/rust-lang/rust/pull/22158
8177 [ufcs-rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0132-ufcs.md
8178 [un]: https://github.com/rust-lang/rust/pull/22256
8179
8180
8181 Version 1.0.0-alpha (2015-01-09)
8182 ==================================
8183
8184   * ~2400 changes, numerous bugfixes
8185
8186   * Highlights
8187
8188     * The language itself is considered feature complete for 1.0,
8189       though there will be many usability improvements and bugfixes
8190       before the final release.
8191     * Nearly 50% of the public API surface of the standard library has
8192       been declared 'stable'. Those interfaces are unlikely to change
8193       before 1.0.
8194     * The long-running debate over integer types has been
8195       [settled][ints]: Rust will ship with types named `isize` and
8196       `usize`, rather than `int` and `uint`, for pointer-sized
8197       integers. Guidelines will be rolled out during the alpha cycle.
8198     * Most crates that are not `std` have been moved out of the Rust
8199       distribution into the Cargo ecosystem so they can evolve
8200       separately and don't need to be stabilized as quickly, including
8201       'time', 'getopts', 'num', 'regex', and 'term'.
8202     * Documentation continues to be expanded with more API coverage, more
8203       examples, and more in-depth explanations. The guides have been
8204       consolidated into [The Rust Programming Language][trpl].
8205     * "[Rust By Example][rbe]" is now maintained by the Rust team.
8206     * All official Rust binary installers now come with [Cargo], the
8207       Rust package manager.
8208
8209 * Language
8210
8211     * Closures have been [completely redesigned][unboxed] to be
8212       implemented in terms of traits, can now be used as generic type
8213       bounds and thus monomorphized and inlined, or via an opaque
8214       pointer (boxed) as in the old system. The new system is often
8215       referred to as 'unboxed' closures.
8216     * Traits now support [associated types][assoc], allowing families
8217       of related types to be defined together and used generically in
8218       powerful ways.
8219     * Enum variants are [namespaced by their type names][enum].
8220     * [`where` clauses][where] provide a more versatile and attractive
8221       syntax for specifying generic bounds, though the previous syntax
8222       remains valid.
8223     * Rust again picks a [fallback][fb] (either i32 or f64) for uninferred
8224       numeric types.
8225     * Rust [no longer has a runtime][rt] of any description, and only
8226       supports OS threads, not green threads.
8227     * At long last, Rust has been overhauled for 'dynamically-sized
8228       types' ([DST]), which integrates 'fat pointers' (object types,
8229       arrays, and `str`) more deeply into the type system, making it
8230       more consistent.
8231     * Rust now has a general [range syntax][range], `i..j`, `i..`, and
8232       `..j` that produce range types and which, when combined with the
8233       `Index` operator and multidispatch, leads to a convenient slice
8234       notation, `[i..j]`.
8235     * The new range syntax revealed an ambiguity in the fixed-length
8236       array syntax, so now fixed length arrays [are written `[T;
8237       N]`][arrays].
8238     * The `Copy` trait is no longer implemented automatically. Unsafe
8239       pointers no longer implement `Sync` and `Send` so types
8240       containing them don't automatically either. `Sync` and `Send`
8241       are now 'unsafe traits' so one can "forcibly" implement them via
8242       `unsafe impl` if a type confirms to the requirements for them
8243       even though the internals do not (e.g. structs containing unsafe
8244       pointers like `Arc`). These changes are intended to prevent some
8245       footguns and are collectively known as [opt-in built-in
8246       traits][oibit] (though `Sync` and `Send` will soon become pure
8247       library types unknown to the compiler).
8248     * Operator traits now take their operands [by value][ops], and
8249       comparison traits can use multidispatch to compare one type
8250       against multiple other types, allowing e.g. `String` to be
8251       compared with `&str`.
8252     * `if let` and `while let` are no longer feature-gated.
8253     * Rust has adopted a more [uniform syntax for escaping unicode
8254       characters][unicode].
8255     * `macro_rules!` [has been declared stable][mac]. Though it is a
8256       flawed system it is sufficiently popular that it must be usable
8257       for 1.0. Effort has gone into [future-proofing][mac-future] it
8258       in ways that will allow other macro systems to be developed in
8259       parallel, and won't otherwise impact the evolution of the
8260       language.
8261     * The prelude has been [pared back significantly][prelude] such
8262       that it is the minimum necessary to support the most pervasive
8263       code patterns, and through [generalized where clauses][where]
8264       many of the prelude extension traits have been consolidated.
8265     * Rust's rudimentary reflection [has been removed][refl], as it
8266       incurred too much code generation for little benefit.
8267     * [Struct variants][structvars] are no longer feature-gated.
8268     * Trait bounds can be [polymorphic over lifetimes][hrtb]. Also
8269       known as 'higher-ranked trait bounds', this crucially allows
8270       unboxed closures to work.
8271     * Macros invocations surrounded by parens or square brackets and
8272       not terminated by a semicolon are [parsed as
8273       expressions][macros], which makes expressions like `vec![1i32,
8274       2, 3].len()` work as expected.
8275     * Trait objects now implement their traits automatically, and
8276       traits that can be coerced to objects now must be [object
8277       safe][objsafe].
8278     * Automatically deriving traits is now done with `#[derive(...)]`
8279       not `#[deriving(...)]` for [consistency with other naming
8280       conventions][derive].
8281     * Importing the containing module or enum at the same time as
8282       items or variants they contain is [now done with `self` instead
8283       of `mod`][self], as in use `foo::{self, bar}`
8284     * Glob imports are no longer feature-gated.
8285     * The `box` operator and `box` patterns have been feature-gated
8286       pending a redesign. For now unique boxes should be allocated
8287       like other containers, with `Box::new`.
8288
8289 * Libraries
8290
8291     * A [series][coll1] of [efforts][coll2] to establish
8292       [conventions][coll3] for collections types has resulted in API
8293       improvements throughout the standard library.
8294     * New [APIs for error handling][err] provide ergonomic interop
8295       between error types, and [new conventions][err-conv] describe
8296       more clearly the recommended error handling strategies in Rust.
8297     * The `fail!` macro has been renamed to [`panic!`][panic] so that
8298       it is easier to discuss failure in the context of error handling
8299       without making clarifications as to whether you are referring to
8300       the 'fail' macro or failure more generally.
8301     * On Linux, `OsRng` prefers the new, more reliable `getrandom`
8302       syscall when available.
8303     * The 'serialize' crate has been renamed 'rustc-serialize' and
8304       moved out of the distribution to Cargo. Although it is widely
8305       used now, it is expected to be superseded in the near future.
8306     * The `Show` formatter, typically implemented with
8307       `#[derive(Show)]` is [now requested with the `{:?}`
8308       specifier][show] and is intended for use by all types, for uses
8309       such as `println!` debugging. The new `String` formatter must be
8310       implemented by hand, uses the `{}` specifier, and is intended
8311       for full-fidelity conversions of things that can logically be
8312       represented as strings.
8313
8314 * Tooling
8315
8316     * [Flexible target specification][flex] allows rustc's code
8317       generation to be configured to support otherwise-unsupported
8318       platforms.
8319     * Rust comes with rust-gdb and rust-lldb scripts that launch their
8320       respective debuggers with Rust-appropriate pretty-printing.
8321     * The Windows installation of Rust is distributed with the
8322       MinGW components currently required to link binaries on that
8323       platform.
8324
8325 * Misc
8326
8327     * Nullable enum optimizations have been extended to more types so
8328       that e.g. `Option<Vec<T>>` and `Option<String>` take up no more
8329       space than the inner types themselves.
8330     * Work has begun on supporting AArch64.
8331
8332 [Cargo]: https://crates.io
8333 [unboxed]: http://smallcultfollowing.com/babysteps/blog/2014/11/26/purging-proc/
8334 [enum]: https://github.com/rust-lang/rfcs/blob/master/text/0390-enum-namespacing.md
8335 [flex]: https://github.com/rust-lang/rfcs/blob/master/text/0131-target-specification.md
8336 [err]: https://github.com/rust-lang/rfcs/blob/master/text/0201-error-chaining.md
8337 [err-conv]: https://github.com/rust-lang/rfcs/blob/master/text/0236-error-conventions.md
8338 [rt]: https://github.com/rust-lang/rfcs/blob/master/text/0230-remove-runtime.md
8339 [mac]: https://github.com/rust-lang/rfcs/blob/master/text/0453-macro-reform.md
8340 [mac-future]: https://github.com/rust-lang/rfcs/pull/550
8341 [DST]: http://smallcultfollowing.com/babysteps/blog/2014/01/05/dst-take-5/
8342 [coll1]: https://github.com/rust-lang/rfcs/blob/master/text/0235-collections-conventions.md
8343 [coll2]: https://github.com/rust-lang/rfcs/blob/master/text/0509-collections-reform-part-2.md
8344 [coll3]: https://github.com/rust-lang/rfcs/blob/master/text/0216-collection-views.md
8345 [ops]: https://github.com/rust-lang/rfcs/blob/master/text/0439-cmp-ops-reform.md
8346 [prelude]: https://github.com/rust-lang/rfcs/blob/master/text/0503-prelude-stabilization.md
8347 [where]: https://github.com/rust-lang/rfcs/blob/master/text/0135-where.md
8348 [refl]: https://github.com/rust-lang/rfcs/blob/master/text/0379-remove-reflection.md
8349 [panic]: https://github.com/rust-lang/rfcs/blob/master/text/0221-panic.md
8350 [structvars]: https://github.com/rust-lang/rfcs/blob/master/text/0418-struct-variants.md
8351 [hrtb]: https://github.com/rust-lang/rfcs/blob/master/text/0387-higher-ranked-trait-bounds.md
8352 [unicode]: https://github.com/rust-lang/rfcs/blob/master/text/0446-es6-unicode-escapes.md
8353 [oibit]: https://github.com/rust-lang/rfcs/blob/master/text/0019-opt-in-builtin-traits.md
8354 [macros]: https://github.com/rust-lang/rfcs/blob/master/text/0378-expr-macros.md
8355 [range]: https://github.com/rust-lang/rfcs/blob/master/text/0439-cmp-ops-reform.md#indexing-and-slicing
8356 [arrays]: https://github.com/rust-lang/rfcs/blob/master/text/0520-new-array-repeat-syntax.md
8357 [show]: https://github.com/rust-lang/rfcs/blob/master/text/0504-show-stabilization.md
8358 [derive]: https://github.com/rust-lang/rfcs/blob/master/text/0534-deriving2derive.md
8359 [self]: https://github.com/rust-lang/rfcs/blob/master/text/0532-self-in-use.md
8360 [fb]: https://github.com/rust-lang/rfcs/blob/master/text/0212-restore-int-fallback.md
8361 [objsafe]: https://github.com/rust-lang/rfcs/blob/master/text/0255-object-safety.md
8362 [assoc]: https://github.com/rust-lang/rfcs/blob/master/text/0195-associated-items.md
8363 [ints]: https://github.com/rust-lang/rfcs/pull/544#issuecomment-68760871
8364 [trpl]: https://doc.rust-lang.org/book/index.html
8365 [rbe]: http://rustbyexample.com/
8366
8367
8368 Version 0.12.0 (2014-10-09)
8369 =============================
8370
8371   * ~1900 changes, numerous bugfixes
8372
8373   * Highlights
8374
8375     * The introductory documentation (now called The Rust Guide) has
8376       been completely rewritten, as have a number of supplementary
8377       guides.
8378     * Rust's package manager, Cargo, continues to improve and is
8379       sometimes considered to be quite awesome.
8380     * Many API's in `std` have been reviewed and updated for
8381       consistency with the in-development Rust coding
8382       guidelines. The standard library documentation tracks
8383       stabilization progress.
8384     * Minor libraries have been moved out-of-tree to the rust-lang org
8385       on GitHub: uuid, semver, glob, num, hexfloat, fourcc. They can
8386       be installed with Cargo.
8387     * Lifetime elision allows lifetime annotations to be left off of
8388       function declarations in many common scenarios.
8389     * Rust now works on 64-bit Windows.
8390
8391   * Language
8392     * Indexing can be overloaded with the `Index` and `IndexMut`
8393       traits.
8394     * The `if let` construct takes a branch only if the `let` pattern
8395       matches, currently behind the 'if_let' feature gate.
8396     * 'where clauses', a more flexible syntax for specifying trait
8397       bounds that is more aesthetic, have been added for traits and
8398       free functions. Where clauses will in the future make it
8399       possible to constrain associated types, which would be
8400       impossible with the existing syntax.
8401     * A new slicing syntax (e.g. `[0..4]`) has been introduced behind
8402       the 'slicing_syntax' feature gate, and can be overloaded with
8403       the `Slice` or `SliceMut` traits.
8404     * The syntax for matching of sub-slices has been changed to use a
8405       postfix `..` instead of prefix (.e.g. `[a, b, c..]`), for
8406       consistency with other uses of `..` and to future-proof
8407       potential additional uses of the syntax.
8408     * The syntax for matching inclusive ranges in patterns has changed
8409       from `0..3` to `0...4` to be consistent with the exclusive range
8410       syntax for slicing.
8411     * Matching of sub-slices in non-tail positions (e.g.  `[a.., b,
8412       c]`) has been put behind the 'advanced_slice_patterns' feature
8413       gate and may be removed in the future.
8414     * Components of tuples and tuple structs can be extracted using
8415       the `value.0` syntax, currently behind the `tuple_indexing`
8416       feature gate.
8417     * The `#[crate_id]` attribute is no longer supported; versioning
8418       is handled by the package manager.
8419     * Renaming crate imports are now written `extern crate foo as bar`
8420       instead of `extern crate bar = foo`.
8421     * Renaming use statements are now written `use foo as bar` instead
8422       of `use bar = foo`.
8423     * `let` and `match` bindings and argument names in macros are now
8424       hygienic.
8425     * The new, more efficient, closure types ('unboxed closures') have
8426       been added under a feature gate, 'unboxed_closures'. These will
8427       soon replace the existing closure types, once higher-ranked
8428       trait lifetimes are added to the language.
8429     * `move` has been added as a keyword, for indicating closures
8430       that capture by value.
8431     * Mutation and assignment is no longer allowed in pattern guards.
8432     * Generic structs and enums can now have trait bounds.
8433     * The `Share` trait is now called `Sync` to free up the term
8434       'shared' to refer to 'shared reference' (the default reference
8435       type.
8436     * Dynamically-sized types have been mostly implemented,
8437       unifying the behavior of fat-pointer types with the rest of the
8438       type system.
8439     * As part of dynamically-sized types, the `Sized` trait has been
8440       introduced, which qualifying types implement by default, and
8441       which type parameters expect by default. To specify that a type
8442       parameter does not need to be sized, write `<Sized? T>`. Most
8443       types are `Sized`, notable exceptions being unsized arrays
8444       (`[T]`) and trait types.
8445     * Closures can return `!`, as in `|| -> !` or `proc() -> !`.
8446     * Lifetime bounds can now be applied to type parameters and object
8447       types.
8448     * The old, reference counted GC type, `Gc<T>` which was once
8449       denoted by the `@` sigil, has finally been removed. GC will be
8450       revisited in the future.
8451
8452   * Libraries
8453     * Library documentation has been improved for a number of modules.
8454     * Bit-vectors, collections::bitv has been modernized.
8455     * The url crate is deprecated in favor of
8456       http://github.com/servo/rust-url, which can be installed with
8457       Cargo.
8458     * Most I/O stream types can be cloned and subsequently closed from
8459       a different thread.
8460     * A `std::time::Duration` type has been added for use in I/O
8461       methods that rely on timers, as well as in the 'time' crate's
8462       `Timespec` arithmetic.
8463     * The runtime I/O abstraction layer that enabled the green thread
8464       scheduler to do non-thread-blocking I/O has been removed, along
8465       with the libuv-based implementation employed by the green thread
8466       scheduler. This will greatly simplify the future I/O work.
8467     * `collections::btree` has been rewritten to have a more
8468       idiomatic and efficient design.
8469
8470   * Tooling
8471     * rustdoc output now indicates the stability levels of API's.
8472     * The `--crate-name` flag can specify the name of the crate
8473       being compiled, like `#[crate_name]`.
8474     * The `-C metadata` specifies additional metadata to hash into
8475       symbol names, and `-C extra-filename` specifies additional
8476       information to put into the output filename, for use by the
8477       package manager for versioning.
8478     * debug info generation has continued to improve and should be
8479       more reliable under both gdb and lldb.
8480     * rustc has experimental support for compiling in parallel
8481       using the `-C codegen-units` flag.
8482     * rustc no longer encodes rpath information into binaries by
8483       default.
8484
8485   * Misc
8486     * Stack usage has been optimized with LLVM lifetime annotations.
8487     * Official Rust binaries on Linux are more compatible with older
8488       kernels and distributions, built on CentOS 5.10.
8489
8490
8491 Version 0.11.0 (2014-07-02)
8492 ==========================
8493
8494   * ~1700 changes, numerous bugfixes
8495
8496   * Language
8497     * ~[T] has been removed from the language. This type is superseded by
8498       the Vec<T> type.
8499     * ~str has been removed from the language. This type is superseded by
8500       the String type.
8501     * ~T has been removed from the language. This type is superseded by the
8502       Box<T> type.
8503     * @T has been removed from the language. This type is superseded by the
8504       standard library's std::gc::Gc<T> type.
8505     * Struct fields are now all private by default.
8506     * Vector indices and shift amounts are both required to be a `uint`
8507       instead of any integral type.
8508     * Byte character, byte string, and raw byte string literals are now all
8509       supported by prefixing the normal literal with a `b`.
8510     * Multiple ABIs are no longer allowed in an ABI string
8511     * The syntax for lifetimes on closures/procedures has been tweaked
8512       slightly: `<'a>|A, B|: 'b + K -> T`
8513     * Floating point modulus has been removed from the language; however it
8514       is still provided by a library implementation.
8515     * Private enum variants are now disallowed.
8516     * The `priv` keyword has been removed from the language.
8517     * A closure can no longer be invoked through a &-pointer.
8518     * The `use foo, bar, baz;` syntax has been removed from the language.
8519     * The transmute intrinsic no longer works on type parameters.
8520     * Statics now allow blocks/items in their definition.
8521     * Trait bounds are separated from objects with + instead of : now.
8522     * Objects can no longer be read while they are mutably borrowed.
8523     * The address of a static is now marked as insignificant unless the
8524       #[inline(never)] attribute is placed it.
8525     * The #[unsafe_destructor] attribute is now behind a feature gate.
8526     * Struct literals are no longer allowed in ambiguous positions such as
8527       if, while, match, and for..in.
8528     * Declaration of lang items and intrinsics are now feature-gated by
8529       default.
8530     * Integral literals no longer default to `int`, and floating point
8531       literals no longer default to `f64`. Literals must be suffixed with an
8532       appropriate type if inference cannot determine the type of the
8533       literal.
8534     * The Box<T> type is no longer implicitly borrowed to &mut T.
8535     * Procedures are now required to not capture borrowed references.
8536
8537   * Libraries
8538     * The standard library is now a "facade" over a number of underlying
8539       libraries. This means that development on the standard library should
8540       be speedier due to smaller crates, as well as a clearer line between
8541       all dependencies.
8542     * A new library, libcore, lives under the standard library's facade
8543       which is Rust's "0-assumption" library, suitable for embedded and
8544       kernel development for example.
8545     * A regex crate has been added to the standard distribution. This crate
8546       includes statically compiled regular expressions.
8547     * The unwrap/unwrap_err methods on Result require a Show bound for
8548       better error messages.
8549     * The return types of the std::comm primitives have been centralized
8550       around the Result type.
8551     * A number of I/O primitives have gained the ability to time out their
8552       operations.
8553     * A number of I/O primitives have gained the ability to close their
8554       reading/writing halves to cancel pending operations.
8555     * Reverse iterator methods have been removed in favor of `rev()` on
8556       their forward-iteration counterparts.
8557     * A bitflags! macro has been added to enable easy interop with C and
8558       management of bit flags.
8559     * A debug_assert! macro is now provided which is disabled when
8560       `--cfg ndebug` is passed to the compiler.
8561     * A graphviz crate has been added for creating .dot files.
8562     * The std::cast module has been migrated into std::mem.
8563     * The std::local_data api has been migrated from freestanding functions
8564       to being based on methods.
8565     * The Pod trait has been renamed to Copy.
8566     * jemalloc has been added as the default allocator for types.
8567     * The API for allocating memory has been changed to use proper alignment
8568       and sized deallocation
8569     * Connecting a TcpStream or binding a TcpListener is now based on a
8570       string address and a u16 port. This allows connecting to a hostname as
8571       opposed to an IP.
8572     * The Reader trait now contains a core method, read_at_least(), which
8573       correctly handles many repeated 0-length reads.
8574     * The process-spawning API is now centered around a builder-style
8575       Command struct.
8576     * The :? printing qualifier has been moved from the standard library to
8577       an external libdebug crate.
8578     * Eq/Ord have been renamed to PartialEq/PartialOrd. TotalEq/TotalOrd
8579       have been renamed to Eq/Ord.
8580     * The select/plural methods have been removed from format!. The escapes
8581       for { and } have also changed from \{ and \} to {{ and }},
8582       respectively.
8583     * The TaskBuilder API has been re-worked to be a true builder, and
8584       extension traits for spawning native/green tasks have been added.
8585
8586   * Tooling
8587     * All breaking changes to the language or libraries now have their
8588       commit message annotated with `[breaking-change]` to allow for easy
8589       discovery of breaking changes.
8590     * The compiler will now try to suggest how to annotate lifetimes if a
8591       lifetime-related error occurs.
8592     * Debug info continues to be improved greatly with general bug fixes and
8593       better support for situations like link time optimization (LTO).
8594     * Usage of syntax extensions when cross-compiling has been fixed.
8595     * Functionality equivalent to GCC & Clang's -ffunction-sections,
8596       -fdata-sections and --gc-sections has been enabled by default
8597     * The compiler is now stricter about where it will load module files
8598       from when a module is declared via `mod foo;`.
8599     * The #[phase(syntax)] attribute has been renamed to #[phase(plugin)].
8600       Syntax extensions are now discovered via a "plugin registrar" type
8601       which will be extended in the future to other various plugins.
8602     * Lints have been restructured to allow for dynamically loadable lints.
8603     * A number of rustdoc improvements:
8604       * The HTML output has been visually redesigned.
8605       * Markdown is now powered by hoedown instead of sundown.
8606       * Searching heuristics have been greatly improved.
8607       * The search index has been reduced in size by a great amount.
8608       * Cross-crate documentation via `pub use` has been greatly improved.
8609       * Primitive types are now hyperlinked and documented.
8610     * Documentation has been moved from static.rust-lang.org/doc to
8611       doc.rust-lang.org
8612     * A new sandbox, play.rust-lang.org, is available for running and
8613       sharing rust code examples on-line.
8614     * Unused attributes are now more robustly warned about.
8615     * The dead_code lint now warns about unused struct fields.
8616     * Cross-compiling to iOS is now supported.
8617     * Cross-compiling to mipsel is now supported.
8618     * Stability attributes are now inherited by default and no longer apply
8619       to intra-crate usage, only inter-crate usage.
8620     * Error message related to non-exhaustive match expressions have been
8621       greatly improved.
8622
8623
8624 Version 0.10 (2014-04-03)
8625 =========================
8626
8627   * ~1500 changes, numerous bugfixes
8628
8629   * Language
8630     * A new RFC process is now in place for modifying the language.
8631     * Patterns with `@`-pointers have been removed from the language.
8632     * Patterns with unique vectors (`~[T]`) have been removed from the
8633       language.
8634     * Patterns with unique strings (`~str`) have been removed from the
8635       language.
8636     * `@str` has been removed from the language.
8637     * `@[T]` has been removed from the language.
8638     * `@self` has been removed from the language.
8639     * `@Trait` has been removed from the language.
8640     * Headers on `~` allocations which contain `@` boxes inside the type for
8641       reference counting have been removed.
8642     * The semantics around the lifetimes of temporary expressions have changed,
8643       see #3511 and #11585 for more information.
8644     * Cross-crate syntax extensions are now possible, but feature gated. See
8645       #11151 for more information. This includes both `macro_rules!` macros as
8646       well as syntax extensions such as `format!`.
8647     * New lint modes have been added, and older ones have been turned on to be
8648       warn-by-default.
8649       * Unnecessary parentheses
8650       * Uppercase statics
8651       * Camel Case types
8652       * Uppercase variables
8653       * Publicly visible private types
8654       * `#[deriving]` with raw pointers
8655     * Unsafe functions can no longer be coerced to closures.
8656     * Various obscure macros such as `log_syntax!` are now behind feature gates.
8657     * The `#[simd]` attribute is now behind a feature gate.
8658     * Visibility is no longer allowed on `extern crate` statements, and
8659       unnecessary visibility (`priv`) is no longer allowed on `use` statements.
8660     * Trailing commas are now allowed in argument lists and tuple patterns.
8661     * The `do` keyword has been removed, it is now a reserved keyword.
8662     * Default type parameters have been implemented, but are feature gated.
8663     * Borrowed variables through captures in closures are now considered soundly.
8664     * `extern mod` is now `extern crate`
8665     * The `Freeze` trait has been removed.
8666     * The `Share` trait has been added for types that can be shared among
8667       threads.
8668     * Labels in macros are now hygienic.
8669     * Expression/statement macro invocations can be delimited with `{}` now.
8670     * Treatment of types allowed in `static mut` locations has been tweaked.
8671     * The `*` and `.` operators are now overloadable through the `Deref` and
8672       `DerefMut` traits.
8673     * `~Trait` and `proc` no longer have `Send` bounds by default.
8674     * Partial type hints are now supported with the `_` type marker.
8675     * An `Unsafe` type was introduced for interior mutability. It is now
8676       considered undefined to transmute from `&T` to `&mut T` without using the
8677       `Unsafe` type.
8678     * The #[linkage] attribute was implemented for extern statics/functions.
8679     * The inner attribute syntax has changed from `#[foo];` to `#![foo]`.
8680     * `Pod` was renamed to `Copy`.
8681
8682   * Libraries
8683     * The `libextra` library has been removed. It has now been decomposed into
8684       component libraries with smaller and more focused nuggets of
8685       functionality. The full list of libraries can be found on the
8686       documentation index page.
8687     * std: `std::condition` has been removed. All I/O errors are now propagated
8688       through the `Result` type. In order to assist with error handling, a
8689       `try!` macro for unwrapping errors with an early return and a lint for
8690       unused results has been added. See #12039 for more information.
8691     * std: The `vec` module has been renamed to `slice`.
8692     * std: A new vector type, `Vec<T>`, has been added in preparation for DST.
8693       This will become the only growable vector in the future.
8694     * std: `std::io` now has more public re-exports. Types such as `BufferedReader`
8695       are now found at `std::io::BufferedReader` instead of
8696       `std::io::buffered::BufferedReader`.
8697     * std: `print` and `println` are no longer in the prelude, the `print!` and
8698       `println!` macros are intended to be used instead.
8699     * std: `Rc` now has a `Weak` pointer for breaking cycles, and it no longer
8700       attempts to statically prevent cycles.
8701     * std: The standard distribution is adopting the policy of pushing failure
8702       to the user rather than failing in libraries. Many functions (such as
8703       `slice::last()`) now return `Option<T>` instead of `T` + failing.
8704     * std: `fmt::Default` has been renamed to `fmt::Show`, and it now has a new
8705       deriving mode: `#[deriving(Show)]`.
8706     * std: `ToStr` is now implemented for all types implementing `Show`.
8707     * std: The formatting trait methods now take `&self` instead of `&T`
8708     * std: The `invert()` method on iterators has been renamed to `rev()`
8709     * std: `std::num` has seen a reduction in the genericity of its traits,
8710       consolidating functionality into a few core traits.
8711     * std: Backtraces are now printed on task failure if the environment
8712       variable `RUST_BACKTRACE` is present.
8713     * std: Naming conventions for iterators have been standardized. More details
8714       can be found on the wiki's style guide.
8715     * std: `eof()` has been removed from the `Reader` trait. Specific types may
8716       still implement the function.
8717     * std: Networking types are now cloneable to allow simultaneous reads/writes.
8718     * std: `assert_approx_eq!` has been removed
8719     * std: The `e` and `E` formatting specifiers for floats have been added to
8720       print them in exponential notation.
8721     * std: The `Times` trait has been removed
8722     * std: Indications of variance and opting out of builtin bounds is done
8723       through marker types in `std::kinds::marker` now
8724     * std: `hash` has been rewritten, `IterBytes` has been removed, and
8725       `#[deriving(Hash)]` is now possible.
8726     * std: `SharedChan` has been removed, `Sender` is now cloneable.
8727     * std: `Chan` and `Port` were renamed to `Sender` and `Receiver`.
8728     * std: `Chan::new` is now `channel()`.
8729     * std: A new synchronous channel type has been implemented.
8730     * std: A `select!` macro is now provided for selecting over `Receiver`s.
8731     * std: `hashmap` and `trie` have been moved to `libcollections`
8732     * std: `run` has been rolled into `io::process`
8733     * std: `assert_eq!` now uses `{}` instead of `{:?}`
8734     * std: The equality and comparison traits have seen some reorganization.
8735     * std: `rand` has moved to `librand`.
8736     * std: `to_{lower,upper}case` has been implemented for `char`.
8737     * std: Logging has been moved to `liblog`.
8738     * collections: `HashMap` has been rewritten for higher performance and less
8739       memory usage.
8740     * native: The default runtime is now `libnative`. If `libgreen` is desired,
8741       it can be booted manually. The runtime guide has more information and
8742       examples.
8743     * native: All I/O functionality except signals has been implemented.
8744     * green: Task spawning with `libgreen` has been optimized with stack caching
8745       and various trimming of code.
8746     * green: Tasks spawned by `libgreen` now have an unmapped guard page.
8747     * sync: The `extra::sync` module has been updated to modern rust (and moved
8748       to the `sync` library), tweaking and improving various interfaces while
8749       dropping redundant functionality.
8750     * sync: A new `Barrier` type has been added to the `sync` library.
8751     * sync: An efficient mutex for native and green tasks has been implemented.
8752     * serialize: The `base64` module has seen some improvement. It treats
8753       newlines better, has non-string error values, and has seen general
8754       cleanup.
8755     * fourcc: A `fourcc!` macro was introduced
8756     * hexfloat: A `hexfloat!` macro was implemented for specifying floats via a
8757       hexadecimal literal.
8758
8759   * Tooling
8760     * `rustpkg` has been deprecated and removed from the main repository. Its
8761       replacement, `cargo`, is under development.
8762     * Nightly builds of rust are now available
8763     * The memory usage of rustc has been improved many times throughout this
8764       release cycle.
8765     * The build process supports disabling rpath support for the rustc binary
8766       itself.
8767     * Code generation has improved in some cases, giving more information to the
8768       LLVM optimization passes to enable more extensive optimizations.
8769     * Debuginfo compatibility with lldb on OSX has been restored.
8770     * The master branch is now gated on an android bot, making building for
8771       android much more reliable.
8772     * Output flags have been centralized into one `--emit` flag.
8773     * Crate type flags have been centralized into one `--crate-type` flag.
8774     * Codegen flags have been consolidated behind a `-C` flag.
8775     * Linking against outdated crates now has improved error messages.
8776     * Error messages with lifetimes will often suggest how to annotate the
8777       function to fix the error.
8778     * Many more types are documented in the standard library, and new guides
8779       were written.
8780     * Many `rustdoc` improvements:
8781       * code blocks are syntax highlighted.
8782       * render standalone markdown files.
8783       * the --test flag tests all code blocks by default.
8784       * exported macros are displayed.
8785       * re-exported types have their documentation inlined at the location of the
8786         first re-export.
8787       * search works across crates that have been rendered to the same output
8788         directory.
8789
8790
8791 Version 0.9 (2014-01-09)
8792 ==========================
8793
8794    * ~1800 changes, numerous bugfixes
8795
8796    * Language
8797       * The `float` type has been removed. Use `f32` or `f64` instead.
8798       * A new facility for enabling experimental features (feature gating) has
8799         been added, using the crate-level `#[feature(foo)]` attribute.
8800       * Managed boxes (@) are now behind a feature gate
8801         (`#[feature(managed_boxes)]`) in preparation for future removal. Use the
8802         standard library's `Gc` or `Rc` types instead.
8803       * `@mut` has been removed. Use `std::cell::{Cell, RefCell}` instead.
8804       * Jumping back to the top of a loop is now done with `continue` instead of
8805         `loop`.
8806       * Strings can no longer be mutated through index assignment.
8807       * Raw strings can be created via the basic `r"foo"` syntax or with matched
8808         hash delimiters, as in `r###"foo"###`.
8809       * `~fn` is now written `proc (args) -> retval { ... }` and may only be
8810         called once.
8811       * The `&fn` type is now written `|args| -> ret` to match the literal form.
8812       * `@fn`s have been removed.
8813       * `do` only works with procs in order to make it obvious what the cost
8814         of `do` is.
8815       * Single-element tuple-like structs can no longer be dereferenced to
8816         obtain the inner value. A more comprehensive solution for overloading
8817         the dereference operator will be provided in the future.
8818       * The `#[link(...)]` attribute has been replaced with
8819         `#[crate_id = "name#vers"]`.
8820       * Empty `impl`s must be terminated with empty braces and may not be
8821         terminated with a semicolon.
8822       * Keywords are no longer allowed as lifetime names; the `self` lifetime
8823         no longer has any special meaning.
8824       * The old `fmt!` string formatting macro has been removed.
8825       * `printf!` and `printfln!` (old-style formatting) removed in favor of
8826         `print!` and `println!`.
8827       * `mut` works in patterns now, as in `let (mut x, y) = (1, 2);`.
8828       * The `extern mod foo (name = "bar")` syntax has been removed. Use
8829         `extern mod foo = "bar"` instead.
8830       * New reserved keywords: `alignof`, `offsetof`, `sizeof`.
8831       * Macros can have attributes.
8832       * Macros can expand to items with attributes.
8833       * Macros can expand to multiple items.
8834       * The `asm!` macro is feature-gated (`#[feature(asm)]`).
8835       * Comments may be nested.
8836       * Values automatically coerce to trait objects they implement, without
8837         an explicit `as`.
8838       * Enum discriminants are no longer an entire word but as small as needed to
8839         contain all the variants. The `repr` attribute can be used to override
8840         the discriminant size, as in `#[repr(int)]` for integer-sized, and
8841         `#[repr(C)]` to match C enums.
8842       * Non-string literals are not allowed in attributes (they never worked).
8843       * The FFI now supports variadic functions.
8844       * Octal numeric literals, as in `0o7777`.
8845       * The `concat!` syntax extension performs compile-time string concatenation.
8846       * The `#[fixed_stack_segment]` and `#[rust_stack]` attributes have been
8847         removed as Rust no longer uses segmented stacks.
8848       * Non-ascii identifiers are feature-gated (`#[feature(non_ascii_idents)]`).
8849       * Ignoring all fields of an enum variant or tuple-struct is done with `..`,
8850         not `*`; ignoring remaining fields of a struct is also done with `..`,
8851         not `_`; ignoring a slice of a vector is done with `..`, not `.._`.
8852       * `rustc` supports the "win64" calling convention via `extern "win64"`.
8853       * `rustc` supports the "system" calling convention, which defaults to the
8854         preferred convention for the target platform, "stdcall" on 32-bit Windows,
8855         "C" elsewhere.
8856       * The `type_overflow` lint (default: warn) checks literals for overflow.
8857       * The `unsafe_block` lint (default: allow) checks for usage of `unsafe`.
8858       * The `attribute_usage` lint (default: warn) warns about unknown
8859         attributes.
8860       * The `unknown_features` lint (default: warn) warns about unknown
8861         feature gates.
8862       * The `dead_code` lint (default: warn) checks for dead code.
8863       * Rust libraries can be linked statically to one another
8864       * `#[link_args]` is behind the `link_args` feature gate.
8865       * Native libraries are now linked with `#[link(name = "foo")]`
8866       * Native libraries can be statically linked to a rust crate
8867         (`#[link(name = "foo", kind = "static")]`).
8868       * Native OS X frameworks are now officially supported
8869         (`#[link(name = "foo", kind = "framework")]`).
8870       * The `#[thread_local]` attribute creates thread-local (not task-local)
8871         variables. Currently behind the `thread_local` feature gate.
8872       * The `return` keyword may be used in closures.
8873       * Types that can be copied via a memcpy implement the `Pod` kind.
8874       * The `cfg` attribute can now be used on struct fields and enum variants.
8875
8876    * Libraries
8877       * std: The `option` and `result` API's have been overhauled to make them
8878         simpler, more consistent, and more composable.
8879       * std: The entire `std::io` module has been replaced with one that is
8880         more comprehensive and that properly interfaces with the underlying
8881         scheduler. File, TCP, UDP, Unix sockets, pipes, and timers are all
8882         implemented.
8883       * std: `io::util` contains a number of useful implementations of
8884         `Reader` and `Writer`, including `NullReader`, `NullWriter`,
8885         `ZeroReader`, `TeeReader`.
8886       * std: The reference counted pointer type `extra::rc` moved into std.
8887       * std: The `Gc` type in the `gc` module will replace `@` (it is currently
8888         just a wrapper around it).
8889       * std: The `Either` type has been removed.
8890       * std: `fmt::Default` can be implemented for any type to provide default
8891         formatting to the `format!` macro, as in `format!("{}", myfoo)`.
8892       * std: The `rand` API continues to be tweaked.
8893       * std: The `rust_begin_unwind` function, useful for inserting breakpoints
8894         on failure in gdb, is now named `rust_fail`.
8895       * std: The `each_key` and `each_value` methods on `HashMap` have been
8896         replaced by the `keys` and `values` iterators.
8897       * std: Functions dealing with type size and alignment have moved from the
8898         `sys` module to the `mem` module.
8899       * std: The `path` module was written and API changed.
8900       * std: `str::from_utf8` has been changed to cast instead of allocate.
8901       * std: `starts_with` and `ends_with` methods added to vectors via the
8902         `ImmutableEqVector` trait, which is in the prelude.
8903       * std: Vectors can be indexed with the `get_opt` method, which returns `None`
8904         if the index is out of bounds.
8905       * std: Task failure no longer propagates between tasks, as the model was
8906         complex, expensive, and incompatible with thread-based tasks.
8907       * std: The `Any` type can be used for dynamic typing.
8908       * std: `~Any` can be passed to the `fail!` macro and retrieved via
8909         `task::try`.
8910       * std: Methods that produce iterators generally do not have an `_iter`
8911         suffix now.
8912       * std: `cell::Cell` and `cell::RefCell` can be used to introduce mutability
8913         roots (mutable fields, etc.). Use instead of e.g. `@mut`.
8914       * std: `util::ignore` renamed to `prelude::drop`.
8915       * std: Slices have `sort` and `sort_by` methods via the `MutableVector`
8916         trait.
8917       * std: `vec::raw` has seen a lot of cleanup and API changes.
8918       * std: The standard library no longer includes any C++ code, and very
8919         minimal C, eliminating the dependency on libstdc++.
8920       * std: Runtime scheduling and I/O functionality has been factored out into
8921         extensible interfaces and is now implemented by two different crates:
8922         libnative, for native threading and I/O; and libgreen, for green threading
8923         and I/O. This paves the way for using the standard library in more limited
8924         embedded environments.
8925       * std: The `comm` module has been rewritten to be much faster, have a
8926         simpler, more consistent API, and to work for both native and green
8927         threading.
8928       * std: All libuv dependencies have been moved into the rustuv crate.
8929       * native: New implementations of runtime scheduling on top of OS threads.
8930       * native: New native implementations of TCP, UDP, file I/O, process spawning,
8931         and other I/O.
8932       * green: The green thread scheduler and message passing types are almost
8933         entirely lock-free.
8934       * extra: The `flatpipes` module had bitrotted and was removed.
8935       * extra: All crypto functions have been removed and Rust now has a policy of
8936         not reimplementing crypto in the standard library. In the future crypto
8937         will be provided by external crates with bindings to established libraries.
8938       * extra: `c_vec` has been modernized.
8939       * extra: The `sort` module has been removed. Use the `sort` method on
8940         mutable slices.
8941
8942    * Tooling
8943       * The `rust` and `rusti` commands have been removed, due to lack of
8944         maintenance.
8945       * `rustdoc` was completely rewritten.
8946       * `rustdoc` can test code examples in documentation.
8947       * `rustpkg` can test packages with the argument, 'test'.
8948       * `rustpkg` supports arbitrary dependencies, including C libraries.
8949       * `rustc`'s support for generating debug info is improved again.
8950       * `rustc` has better error reporting for unbalanced delimiters.
8951       * `rustc`'s JIT support was removed due to bitrot.
8952       * Executables and static libraries can be built with LTO (-Z lto)
8953       * `rustc` adds a `--dep-info` flag for communicating dependencies to
8954         build tools.
8955
8956
8957 Version 0.8 (2013-09-26)
8958 ============================
8959
8960    * ~2200 changes, numerous bugfixes
8961
8962    * Language
8963       * The `for` loop syntax has changed to work with the `Iterator` trait.
8964       * At long last, unwinding works on Windows.
8965       * Default methods are ready for use.
8966       * Many trait inheritance bugs fixed.
8967       * Owned and borrowed trait objects work more reliably.
8968       * `copy` is no longer a keyword. It has been replaced by the `Clone` trait.
8969       * rustc can omit emission of code for the `debug!` macro if it is passed
8970         `--cfg ndebug`
8971       * mod.rs is now "blessed". When loading `mod foo;`, rustc will now look
8972         for foo.rs, then foo/mod.rs, and will generate an error when both are
8973         present.
8974       * Strings no longer contain trailing nulls. The new `std::c_str` module
8975         provides new mechanisms for converting to C strings.
8976       * The type of foreign functions is now `extern "C" fn` instead of `*u8'.
8977       * The FFI has been overhauled such that foreign functions are called directly,
8978         instead of through a stack-switching wrapper.
8979       * Calling a foreign function must be done through a Rust function with the
8980         `#[fixed_stack_segment]` attribute.
8981       * The `externfn!` macro can be used to declare both a foreign function and
8982         a `#[fixed_stack_segment]` wrapper at once.
8983       * `pub` and `priv` modifiers on `extern` blocks are no longer parsed.
8984       * `unsafe` is no longer allowed on extern fns - they are all unsafe.
8985       * `priv` is disallowed everywhere except for struct fields and enum variants.
8986       * `&T` (besides `&'static T`) is no longer allowed in `@T`.
8987       * `ref` bindings in irrefutable patterns work correctly now.
8988       * `char` is now prevented from containing invalid code points.
8989       * Casting to `bool` is no longer allowed.
8990       * `\0` is now accepted as an escape in chars and strings.
8991       * `yield` is a reserved keyword.
8992       * `typeof` is a reserved keyword.
8993       * Crates may be imported by URL with `extern mod foo = "url";`.
8994       * Explicit enum discriminants may be given as uints as in `enum E { V = 0u }`
8995       * Static vectors can be initialized with repeating elements,
8996         e.g. `static foo: [u8, .. 100]: [0, .. 100];`.
8997       * Static structs can be initialized with functional record update,
8998         e.g. `static foo: Foo = Foo { a: 5, .. bar };`.
8999       * `cfg!` can be used to conditionally execute code based on the crate
9000         configuration, similarly to `#[cfg(...)]`.
9001       * The `unnecessary_qualification` lint detects unneeded module
9002         prefixes (default: allow).
9003       * Arithmetic operations have been implemented on the SIMD types in
9004         `std::unstable::simd`.
9005       * Exchange allocation headers were removed, reducing memory usage.
9006       * `format!` implements a completely new, extensible, and higher-performance
9007         string formatting system. It will replace `fmt!`.
9008       * `print!` and `println!` write formatted strings (using the `format!`
9009         extension) to stdout.
9010       * `write!` and `writeln!` write formatted strings (using the `format!`
9011         extension) to the new Writers in `std::rt::io`.
9012       * The library section in which a function or static is placed may
9013         be specified with `#[link_section = "..."]`.
9014       * The `proto!` syntax extension for defining bounded message protocols
9015         was removed.
9016       * `macro_rules!` is hygienic for `let` declarations.
9017       * The `#[export_name]` attribute specifies the name of a symbol.
9018       * `unreachable!` can be used to indicate unreachable code, and fails
9019         if executed.
9020
9021    * Libraries
9022       * std: Transitioned to the new runtime, written in Rust.
9023       * std: Added an experimental I/O library, `rt::io`, based on the new
9024         runtime.
9025       * std: A new generic `range` function was added to the prelude, replacing
9026         `uint::range` and friends.
9027       * std: `range_rev` no longer exists. Since range is an iterator it can be
9028         reversed with `range(lo, hi).invert()`.
9029       * std: The `chain` method on option renamed to `and_then`; `unwrap_or_default`
9030         renamed to `unwrap_or`.
9031       * std: The `iterator` module was renamed to `iter`.
9032       * std: Integral types now support the `checked_add`, `checked_sub`, and
9033         `checked_mul` operations for detecting overflow.
9034       * std: Many methods in `str`, `vec`, `option, `result` were renamed for
9035         consistency.
9036       * std: Methods are standardizing on conventions for casting methods:
9037         `to_foo` for copying, `into_foo` for moving, `as_foo` for temporary
9038         and cheap casts.
9039       * std: The `CString` type in `c_str` provides new ways to convert to and
9040         from C strings.
9041       * std: `DoubleEndedIterator` can yield elements in two directions.
9042       * std: The `mut_split` method on vectors partitions an `&mut [T]` into
9043         two splices.
9044       * std: `str::from_bytes` renamed to `str::from_utf8`.
9045       * std: `pop_opt` and `shift_opt` methods added to vectors.
9046       * std: The task-local data interface no longer uses @, and keys are
9047         no longer function pointers.
9048       * std: The `swap_unwrap` method of `Option` renamed to `take_unwrap`.
9049       * std: Added `SharedPort` to `comm`.
9050       * std: `Eq` has a default method for `ne`; only `eq` is required
9051         in implementations.
9052       * std: `Ord` has default methods for `le`, `gt` and `ge`; only `lt`
9053         is required in implementations.
9054       * std: `is_utf8` performance is improved, impacting many string functions.
9055       * std: `os::MemoryMap` provides cross-platform mmap.
9056       * std: `ptr::offset` is now unsafe, but also more optimized. Offsets that
9057         are not 'in-bounds' are considered undefined.
9058       * std: Many freestanding functions in `vec` removed in favor of methods.
9059       * std: Many freestanding functions on scalar types removed in favor of
9060         methods.
9061       * std: Many options to task builders were removed since they don't make
9062         sense in the new scheduler design.
9063       * std: More containers implement `FromIterator` so can be created by the
9064         `collect` method.
9065       * std: More complete atomic types in `unstable::atomics`.
9066       * std: `comm::PortSet` removed.
9067       * std: Mutating methods in the `Set` and `Map` traits have been moved into
9068         the `MutableSet` and `MutableMap` traits. `Container::is_empty`,
9069         `Map::contains_key`, `MutableMap::insert`, and `MutableMap::remove` have
9070         default implementations.
9071       * std: Various `from_str` functions were removed in favor of a generic
9072         `from_str` which is available in the prelude.
9073       * std: `util::unreachable` removed in favor of the `unreachable!` macro.
9074       * extra: `dlist`, the doubly-linked list was modernized.
9075       * extra: Added a `hex` module with `ToHex` and `FromHex` traits.
9076       * extra: Added `glob` module, replacing `std::os::glob`.
9077       * extra: `rope` was removed.
9078       * extra: `deque` was renamed to `ringbuf`. `RingBuf` implements `Deque`.
9079       * extra: `net`, and `timer` were removed. The experimental replacements
9080         are `std::rt::io::net` and `std::rt::io::timer`.
9081       * extra: Iterators implemented for `SmallIntMap`.
9082       * extra: Iterators implemented for `Bitv` and `BitvSet`.
9083       * extra: `SmallIntSet` removed. Use `BitvSet`.
9084       * extra: Performance of JSON parsing greatly improved.
9085       * extra: `semver` updated to SemVer 2.0.0.
9086       * extra: `term` handles more terminals correctly.
9087       * extra: `dbg` module removed.
9088       * extra: `par` module removed.
9089       * extra: `future` was cleaned up, with some method renames.
9090       * extra: Most free functions in `getopts` were converted to methods.
9091
9092    * Other
9093       * rustc's debug info generation (`-Z debug-info`) is greatly improved.
9094       * rustc accepts `--target-cpu` to compile to a specific CPU architecture,
9095         similarly to gcc's `--march` flag.
9096       * rustc's performance compiling small crates is much better.
9097       * rustpkg has received many improvements.
9098       * rustpkg supports git tags as package IDs.
9099       * rustpkg builds into target-specific directories so it can be used for
9100         cross-compiling.
9101       * The number of concurrent test tasks is controlled by the environment
9102         variable RUST_TEST_TASKS.
9103       * The test harness can now report metrics for benchmarks.
9104       * All tools have man pages.
9105       * Programs compiled with `--test` now support the `-h` and `--help` flags.
9106       * The runtime uses jemalloc for allocations.
9107       * Segmented stacks are temporarily disabled as part of the transition to
9108         the new runtime. Stack overflows are possible!
9109       * A new documentation backend, rustdoc_ng, is available for use. It is
9110         still invoked through the normal `rustdoc` command.
9111
9112
9113 Version 0.7 (2013-07-03)
9114 =======================
9115
9116    * ~2000 changes, numerous bugfixes
9117
9118    * Language
9119       * `impl`s no longer accept a visibility qualifier. Put them on methods
9120         instead.
9121       * The borrow checker has been rewritten with flow-sensitivity, fixing
9122         many bugs and inconveniences.
9123       * The `self` parameter no longer implicitly means `&'self self`,
9124         and can be explicitly marked with a lifetime.
9125       * Overloadable compound operators (`+=`, etc.) have been temporarily
9126         removed due to bugs.
9127       * The `for` loop protocol now requires `for`-iterators to return `bool`
9128         so they compose better.
9129       * The `Durable` trait is replaced with the `'static` bounds.
9130       * Trait default methods work more often.
9131       * Structs with the `#[packed]` attribute have byte alignment and
9132         no padding between fields.
9133       * Type parameters bound by `Copy` must now be copied explicitly with
9134         the `copy` keyword.
9135       * It is now illegal to move out of a dereferenced unsafe pointer.
9136       * `Option<~T>` is now represented as a nullable pointer.
9137       * `@mut` does dynamic borrow checks correctly.
9138       * The `main` function is only detected at the topmost level of the crate.
9139         The `#[main]` attribute is still valid anywhere.
9140       * Struct fields may no longer be mutable. Use inherited mutability.
9141       * The `#[no_send]` attribute makes a type that would otherwise be
9142         `Send`, not.
9143       * The `#[no_freeze]` attribute makes a type that would otherwise be
9144         `Freeze`, not.
9145       * Unbounded recursion will abort the process after reaching the limit
9146         specified by the `RUST_MAX_STACK` environment variable (default: 1GB).
9147       * The `vecs_implicitly_copyable` lint mode has been removed. Vectors
9148         are never implicitly copyable.
9149       * `#[static_assert]` makes compile-time assertions about static bools.
9150       * At long last, 'argument modes' no longer exist.
9151       * The rarely used `use mod` statement no longer exists.
9152
9153    * Syntax extensions
9154       * `fail!` and `assert!` accept `~str`, `&'static str` or `fmt!`-style
9155         argument list.
9156       * `Encodable`, `Decodable`, `Ord`, `TotalOrd`, `TotalEq`, `DeepClone`,
9157         `Rand`, `Zero` and `ToStr` can all be automatically derived with
9158         `#[deriving(...)]`.
9159       * The `bytes!` macro returns a vector of bytes for string, u8, char,
9160         and unsuffixed integer literals.
9161
9162    * Libraries
9163       * The `core` crate was renamed to `std`.
9164       * The `std` crate was renamed to `extra`.
9165       * More and improved documentation.
9166       * std: `iterator` module for external iterator objects.
9167       * Many old-style (internal, higher-order function) iterators replaced by
9168         implementations of `Iterator`.
9169       * std: Many old internal vector and string iterators,
9170         incl. `any`, `all`. removed.
9171       * std: The `finalize` method of `Drop` renamed to `drop`.
9172       * std: The `drop` method now takes `&mut self` instead of `&self`.
9173       * std: The prelude no longer re-exports any modules, only types and traits.
9174       * std: Prelude additions: `print`, `println`, `FromStr`, `ApproxEq`, `Equiv`,
9175         `Iterator`, `IteratorUtil`, many numeric traits, many tuple traits.
9176       * std: New numeric traits: `Fractional`, `Real`, `RealExt`, `Integer`, `Ratio`,
9177         `Algebraic`, `Trigonometric`, `Exponential`, `Primitive`.
9178       * std: Tuple traits and accessors defined for up to 12-tuples, e.g.
9179         `(0, 1, 2).n2()` or `(0, 1, 2).n2_ref()`.
9180       * std: Many types implement `Clone`.
9181       * std: `path` type renamed to `Path`.
9182       * std: `mut` module and `Mut` type removed.
9183       * std: Many standalone functions removed in favor of methods and iterators
9184         in `vec`, `str`. In the future methods will also work as functions.
9185       * std: `reinterpret_cast` removed. Use `transmute`.
9186       * std: ascii string handling in `std::ascii`.
9187       * std: `Rand` is implemented for ~/@.
9188       * std: `run` module for spawning processes overhauled.
9189       * std: Various atomic types added to `unstable::atomic`.
9190       * std: Various types implement `Zero`.
9191       * std: `LinearMap` and `LinearSet` renamed to `HashMap` and `HashSet`.
9192       * std: Borrowed pointer functions moved from `ptr` to `borrow`.
9193       * std: Added `os::mkdir_recursive`.
9194       * std: Added `os::glob` function performs filesystems globs.
9195       * std: `FuzzyEq` renamed to `ApproxEq`.
9196       * std: `Map` now defines `pop` and `swap` methods.
9197       * std: `Cell` constructors converted to static methods.
9198       * extra: `rc` module adds the reference counted pointers, `Rc` and `RcMut`.
9199       * extra: `flate` module moved from `std` to `extra`.
9200       * extra: `fileinput` module for iterating over a series of files.
9201       * extra: `Complex` number type and `complex` module.
9202       * extra: `Rational` number type and `rational` module.
9203       * extra: `BigInt`, `BigUint` implement numeric and comparison traits.
9204       * extra: `term` uses terminfo now, is more correct.
9205       * extra: `arc` functions converted to methods.
9206       * extra: Implementation of fixed output size variations of SHA-2.
9207
9208    * Tooling
9209       * `unused_variables` lint mode for unused variables (default: warn).
9210       * `unused_unsafe` lint mode for detecting unnecessary `unsafe` blocks
9211         (default: warn).
9212       * `unused_mut` lint mode for identifying unused `mut` qualifiers
9213         (default: warn).
9214       * `dead_assignment` lint mode for unread variables (default: warn).
9215       * `unnecessary_allocation` lint mode detects some heap allocations that are
9216         immediately borrowed so could be written without allocating (default: warn).
9217       * `missing_doc` lint mode (default: allow).
9218       * `unreachable_code` lint mode (default: warn).
9219       * The `rusti` command has been rewritten and a number of bugs addressed.
9220       * rustc outputs in color on more terminals.
9221       * rustc accepts a `--link-args` flag to pass arguments to the linker.
9222       * rustc accepts a `-Z print-link-args` flag for debugging linkage.
9223       * Compiling with `-g` will make the binary record information about
9224         dynamic borrowcheck failures for debugging.
9225       * rustdoc has a nicer stylesheet.
9226       * Various improvements to rustdoc.
9227       * Improvements to rustpkg (see the detailed release notes).
9228
9229
9230 Version 0.6 (2013-04-03)
9231 ========================
9232
9233    * ~2100 changes, numerous bugfixes
9234
9235    * Syntax changes
9236       * The self type parameter in traits is now spelled `Self`
9237       * The `self` parameter in trait and impl methods must now be explicitly
9238         named (for example: `fn f(&self) { }`). Implicit self is deprecated.
9239       * Static methods no longer require the `static` keyword and instead
9240         are distinguished by the lack of a `self` parameter
9241       * Replaced the `Durable` trait with the `'static` lifetime
9242       * The old closure type syntax with the trailing sigil has been
9243         removed in favor of the more consistent leading sigil
9244       * `super` is a keyword, and may be prefixed to paths
9245       * Trait bounds are separated with `+` instead of whitespace
9246       * Traits are implemented with `impl Trait for Type`
9247         instead of `impl Type: Trait`
9248       * Lifetime syntax is now `&'l foo` instead of `&l/foo`
9249       * The `export` keyword has finally been removed
9250       * The `move` keyword has been removed (see "Semantic changes")
9251       * The interior mutability qualifier on vectors, `[mut T]`, has been
9252         removed. Use `&mut [T]`, etc.
9253       * `mut` is no longer valid in `~mut T`. Use inherited mutability
9254       * `fail` is no longer a keyword. Use `fail!()`
9255       * `assert` is no longer a keyword. Use `assert!()`
9256       * `log` is no longer a keyword. use `debug!`, etc.
9257       * 1-tuples may be represented as `(T,)`
9258       * Struct fields may no longer be `mut`. Use inherited mutability,
9259         `@mut T`, `core::mut` or `core::cell`
9260       * `extern mod { ... }` is no longer valid syntax for foreign
9261         function modules. Use extern blocks: `extern { ... }`
9262       * Newtype enums removed. Use tuple-structs.
9263       * Trait implementations no longer support visibility modifiers
9264       * Pattern matching over vectors improved and expanded
9265       * `const` renamed to `static` to correspond to lifetime name,
9266         and make room for future `static mut` unsafe mutable globals.
9267       * Replaced `#[deriving_eq]` with `#[deriving(Eq)]`, etc.
9268       * `Clone` implementations can be automatically generated with
9269         `#[deriving(Clone)]`
9270       * Casts to traits must use a pointer sigil, e.g. `@foo as @Bar`
9271         instead of `foo as Bar`.
9272       * Fixed length vector types are now written as `[int, .. 3]`
9273         instead of `[int * 3]`.
9274       * Fixed length vector types can express the length as a constant
9275         expression. (ex: `[int, .. GL_BUFFER_SIZE - 2]`)
9276
9277    * Semantic changes
9278       * Types with owned pointers or custom destructors move by default,
9279         eliminating the `move` keyword
9280       * All foreign functions are considered unsafe
9281       * &mut is now unaliasable
9282       * Writes to borrowed @mut pointers are prevented dynamically
9283       * () has size 0
9284       * The name of the main function can be customized using #[main]
9285       * The default type of an inferred closure is &fn instead of @fn
9286       * `use` statements may no longer be "chained" - they cannot import
9287         identifiers imported by previous `use` statements
9288       * `use` statements are crate relative, importing from the "top"
9289         of the crate by default. Paths may be prefixed with `super::`
9290         or `self::` to change the search behavior.
9291       * Method visibility is inherited from the implementation declaration
9292       * Structural records have been removed
9293       * Many more types can be used in static items, including enums
9294         'static-lifetime pointers and vectors
9295       * Pattern matching over vectors improved and expanded
9296       * Typechecking of closure types has been overhauled to
9297         improve inference and eliminate unsoundness
9298       * Macros leave scope at the end of modules, unless that module is
9299         tagged with #[macro_escape]
9300
9301    * Libraries
9302       * Added big integers to `std::bigint`
9303       * Removed `core::oldcomm` module
9304       * Added pipe-based `core::comm` module
9305       * Numeric traits have been reorganized under `core::num`
9306       * `vec::slice` finally returns a slice
9307       * `debug!` and friends don't require a format string, e.g. `debug!(Foo)`
9308       * Containers reorganized around traits in `core::container`
9309       * `core::dvec` removed, `~[T]` is a drop-in replacement
9310       * `core::send_map` renamed to `core::hashmap`
9311       * `std::map` removed; replaced with `core::hashmap`
9312       * `std::treemap` reimplemented as an owned balanced tree
9313       * `std::deque` and `std::smallintmap` reimplemented as owned containers
9314       * `core::trie` added as a fast ordered map for integer keys
9315       * Set types added to `core::hashmap`, `core::trie` and `std::treemap`
9316       * `Ord` split into `Ord` and `TotalOrd`. `Ord` is still used to
9317         overload the comparison operators, whereas `TotalOrd` is used
9318         by certain container types
9319
9320    * Other
9321       * Replaced the 'cargo' package manager with 'rustpkg'
9322       * Added all-purpose 'rust' tool
9323       * `rustc --test` now supports benchmarks with the `#[bench]` attribute
9324       * rustc now *attempts* to offer spelling suggestions
9325       * Improved support for ARM and Android
9326       * Preliminary MIPS backend
9327       * Improved foreign function ABI implementation for x86, x86_64
9328       * Various memory usage improvements
9329       * Rust code may be embedded in foreign code under limited circumstances
9330       * Inline assembler supported by new asm!() syntax extension.
9331
9332
9333 Version 0.5 (2012-12-21)
9334 ===========================
9335
9336    * ~900 changes, numerous bugfixes
9337
9338    * Syntax changes
9339       * Removed `<-` move operator
9340       * Completed the transition from the `#fmt` extension syntax to `fmt!`
9341       * Removed old fixed length vector syntax - `[T]/N`
9342       * New token-based quasi-quoters, `quote_tokens!`, `quote_expr!`, etc.
9343       * Macros may now expand to items and statements
9344       * `a.b()` is always parsed as a method call, never as a field projection
9345       * `Eq` and `IterBytes` implementations can be automatically generated
9346         with `#[deriving_eq]` and `#[deriving_iter_bytes]` respectively
9347       * Removed the special crate language for `.rc` files
9348       * Function arguments may consist of any irrefutable pattern
9349
9350    * Semantic changes
9351       * `&` and `~` pointers may point to objects
9352       * Tuple structs - `struct Foo(Bar, Baz)`. Will replace newtype enums.
9353       * Enum variants may be structs
9354       * Destructors can be added to all nominal types with the Drop trait
9355       * Structs and nullary enum variants may be constants
9356       * Values that cannot be implicitly copied are now automatically moved
9357         without writing `move` explicitly
9358       * `&T` may now be coerced to `*T`
9359       * Coercions happen in `let` statements as well as function calls
9360       * `use` statements now take crate-relative paths
9361       * The module and type namespaces have been merged so that static
9362         method names can be resolved under the trait in which they are
9363         declared
9364
9365    * Improved support for language features
9366       * Trait inheritance works in many scenarios
9367       * More support for explicit self arguments in methods - `self`, `&self`
9368         `@self`, and `~self` all generally work as expected
9369       * Static methods work in more situations
9370       * Experimental: Traits may declare default methods for the implementations
9371         to use
9372
9373    * Libraries
9374       * New condition handling system in `core::condition`
9375       * Timsort added to `std::sort`
9376       * New priority queue, `std::priority_queue`
9377       * Pipes for serializable types, `std::flatpipes'
9378       * Serialization overhauled to be trait-based
9379       * Expanded `getopts` definitions
9380       * Moved futures to `std`
9381       * More functions are pure now
9382       * `core::comm` renamed to `oldcomm`. Still deprecated
9383       * `rustdoc` and `cargo` are libraries now
9384
9385    * Misc
9386       * Added a preliminary REPL, `rusti`
9387       * License changed from MIT to dual MIT/APL2
9388
9389
9390 Version 0.4 (2012-10-15)
9391 ==========================
9392
9393    * ~2000 changes, numerous bugfixes
9394
9395    * Syntax
9396       * All keywords are now strict and may not be used as identifiers anywhere
9397       * Keyword removal: 'again', 'import', 'check', 'new', 'owned', 'send',
9398         'of', 'with', 'to', 'class'.
9399       * Classes are replaced with simpler structs
9400       * Explicit method self types
9401       * `ret` became `return` and `alt` became `match`
9402       * `import` is now `use`; `use is now `extern mod`
9403       * `extern mod { ... }` is now `extern { ... }`
9404       * `use mod` is the recommended way to import modules
9405       * `pub` and `priv` replace deprecated export lists
9406       * The syntax of `match` pattern arms now uses fat arrow (=>)
9407       * `main` no longer accepts an args vector; use `os::args` instead
9408
9409    * Semantics
9410       * Trait implementations are now coherent, ala Haskell typeclasses
9411       * Trait methods may be static
9412       * Argument modes are deprecated
9413       * Borrowed pointers are much more mature and recommended for use
9414       * Strings and vectors in the static region are stored in constant memory
9415       * Typestate was removed
9416       * Resolution rewritten to be more reliable
9417       * Support for 'dual-mode' data structures (freezing and thawing)
9418
9419    * Libraries
9420       * Most binary operators can now be overloaded via the traits in
9421         `core::ops'
9422       * `std::net::url` for representing URLs
9423       * Sendable hash maps in `core::send_map`
9424       * `core::task' gained a (currently unsafe) task-local storage API
9425
9426    * Concurrency
9427       * An efficient new intertask communication primitive called the pipe,
9428         along with a number of higher-level channel types, in `core::pipes`
9429       * `std::arc`, an atomically reference counted, immutable, shared memory
9430         type
9431       * `std::sync`, various exotic synchronization tools based on arcs and pipes
9432       * Futures are now based on pipes and sendable
9433       * More robust linked task failure
9434       * Improved task builder API
9435
9436    * Other
9437       * Improved error reporting
9438       * Preliminary JIT support
9439       * Preliminary work on precise GC
9440       * Extensive architectural improvements to rustc
9441       * Begun a transition away from buggy C++-based reflection (shape) code to
9442         Rust-based (visitor) code
9443       * All hash functions and tables converted to secure, randomized SipHash
9444
9445
9446 Version 0.3  (2012-07-12)
9447 ========================
9448
9449    * ~1900 changes, numerous bugfixes
9450
9451    * New coding conveniences
9452       * Integer-literal suffix inference
9453       * Per-item control over warnings, errors
9454       * #[cfg(windows)] and #[cfg(unix)] attributes
9455       * Documentation comments
9456       * More compact closure syntax
9457       * 'do' expressions for treating higher-order functions as
9458         control structures
9459       * *-patterns (wildcard extended to all constructor fields)
9460
9461    * Semantic cleanup
9462       * Name resolution pass and exhaustiveness checker rewritten
9463       * Region pointers and borrow checking supersede alias
9464         analysis
9465       * Init-ness checking is now provided by a region-based liveness
9466         pass instead of the typestate pass; same for last-use analysis
9467       * Extensive work on region pointers
9468
9469    * Experimental new language features
9470       * Slices and fixed-size, interior-allocated vectors
9471       * #!-comments for lang versioning, shell execution
9472       * Destructors and iface implementation for classes;
9473         type-parameterized classes and class methods
9474       * 'const' type kind for types that can be used to implement
9475         shared-memory concurrency patterns
9476
9477    * Type reflection
9478
9479    * Removal of various obsolete features
9480       * Keywords: 'be', 'prove', 'syntax', 'note', 'mutable', 'bind',
9481                  'crust', 'native' (now 'extern'), 'cont' (now 'again')
9482
9483       * Constructs: do-while loops ('do' repurposed), fn binding,
9484                     resources (replaced by destructors)
9485
9486    * Compiler reorganization
9487       * Syntax-layer of compiler split into separate crate
9488       * Clang (from LLVM project) integrated into build
9489       * Typechecker split into sub-modules
9490
9491    * New library code
9492       * New time functions
9493       * Extension methods for many built-in types
9494       * Arc: atomic-refcount read-only / exclusive-use shared cells
9495       * Par: parallel map and search routines
9496       * Extensive work on libuv interface
9497       * Much vector code moved to libraries
9498       * Syntax extensions: #line, #col, #file, #mod, #stringify,
9499         #include, #include_str, #include_bin
9500
9501    * Tool improvements
9502       * Cargo automatically resolves dependencies
9503
9504
9505 Version 0.2  (2012-03-29)
9506 =========================
9507
9508    * >1500 changes, numerous bugfixes
9509
9510    * New docs and doc tooling
9511
9512    * New port: FreeBSD x86_64
9513
9514    * Compilation model enhancements
9515       * Generics now specialized, multiply instantiated
9516       * Functions now inlined across separate crates
9517
9518    * Scheduling, stack and threading fixes
9519       * Noticeably improved message-passing performance
9520       * Explicit schedulers
9521       * Callbacks from C
9522       * Helgrind clean
9523
9524    * Experimental new language features
9525       * Operator overloading
9526       * Region pointers
9527       * Classes
9528
9529    * Various language extensions
9530       * C-callback function types: 'crust fn ...'
9531       * Infinite-loop construct: 'loop { ... }'
9532       * Shorten 'mutable' to 'mut'
9533       * Required mutable-local qualifier: 'let mut ...'
9534       * Basic glob-exporting: 'export foo::*;'
9535       * Alt now exhaustive, 'alt check' for runtime-checked
9536       * Block-function form of 'for' loop, with 'break' and 'ret'.
9537
9538    * New library code
9539       * AST quasi-quote syntax extension
9540       * Revived libuv interface
9541       * New modules: core::{future, iter}, std::arena
9542       * Merged per-platform std::{os*, fs*} to core::{libc, os}
9543       * Extensive cleanup, regularization in libstd, libcore
9544
9545
9546 Version 0.1  (2012-01-20)
9547 ===============================
9548
9549    * Most language features work, including:
9550       * Unique pointers, unique closures, move semantics
9551       * Interface-constrained generics
9552       * Static interface dispatch
9553       * Stack growth
9554       * Multithread task scheduling
9555       * Typestate predicates
9556       * Failure unwinding, destructors
9557       * Pattern matching and destructuring assignment
9558       * Lightweight block-lambda syntax
9559       * Preliminary macro-by-example
9560
9561    * Compiler works with the following configurations:
9562       * Linux: x86 and x86_64 hosts and targets
9563       * macOS: x86 and x86_64 hosts and targets
9564       * Windows: x86 hosts and targets
9565
9566    * Cross compilation / multi-target configuration supported.
9567
9568    * Preliminary API-documentation and package-management tools included.
9569
9570 Known issues:
9571
9572    * Documentation is incomplete.
9573
9574    * Performance is below intended target.
9575
9576    * Standard library APIs are subject to extensive change, reorganization.
9577
9578    * Language-level versioning is not yet operational - future code will
9579      break unexpectedly.