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0731742a | 1 | //! This module contains `TyKind` and its major components. |
e9174d1e | 2 | |
e1599b0c | 3 | #![allow(rustc::usage_of_ty_tykind)] |
416331ca | 4 | |
60c5eb7d XL |
5 | use self::TyKind::*; |
6 | ||
9fa01778 | 7 | use crate::infer::canonical::Canonical; |
ba9703b0 | 8 | use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef}; |
5869c6ff | 9 | use crate::ty::InferTy::{self, *}; |
dfeec247 XL |
10 | use crate::ty::{ |
11 | self, AdtDef, DefIdTree, Discr, Ty, TyCtxt, TypeFlags, TypeFoldable, WithConstness, | |
12 | }; | |
3dfed10e | 13 | use crate::ty::{DelaySpanBugEmitted, List, ParamEnv, TyS}; |
60c5eb7d | 14 | use polonius_engine::Atom; |
dfeec247 XL |
15 | use rustc_data_structures::captures::Captures; |
16 | use rustc_hir as hir; | |
3dfed10e | 17 | use rustc_hir::def_id::DefId; |
60c5eb7d XL |
18 | use rustc_index::vec::Idx; |
19 | use rustc_macros::HashStable; | |
6a06907d | 20 | use rustc_span::symbol::{kw, Symbol}; |
3dfed10e | 21 | use rustc_target::abi::VariantIdx; |
60c5eb7d | 22 | use rustc_target::spec::abi; |
48663c56 | 23 | use std::borrow::Cow; |
476ff2be | 24 | use std::cmp::Ordering; |
532ac7d7 | 25 | use std::marker::PhantomData; |
48663c56 | 26 | use std::ops::Range; |
f9f354fc | 27 | use ty::util::IntTypeExt; |
e9174d1e | 28 | |
3dfed10e | 29 | #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
ba9703b0 | 30 | #[derive(HashStable, TypeFoldable, Lift)] |
e9174d1e SL |
31 | pub struct TypeAndMut<'tcx> { |
32 | pub ty: Ty<'tcx>, | |
33 | pub mutbl: hir::Mutability, | |
34 | } | |
35 | ||
3dfed10e | 36 | #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, TyEncodable, TyDecodable, Copy)] |
ba9703b0 | 37 | #[derive(HashStable)] |
e9174d1e SL |
38 | /// A "free" region `fr` can be interpreted as "some region |
39 | /// at least as big as the scope `fr.scope`". | |
40 | pub struct FreeRegion { | |
7cac9316 | 41 | pub scope: DefId, |
fc512014 | 42 | pub bound_region: BoundRegionKind, |
e9174d1e SL |
43 | } |
44 | ||
3dfed10e | 45 | #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, TyEncodable, TyDecodable, Copy)] |
ba9703b0 | 46 | #[derive(HashStable)] |
fc512014 | 47 | pub enum BoundRegionKind { |
e9174d1e SL |
48 | /// An anonymous region parameter for a given fn (&T) |
49 | BrAnon(u32), | |
50 | ||
51 | /// Named region parameters for functions (a in &'a T) | |
52 | /// | |
9fa01778 | 53 | /// The `DefId` is needed to distinguish free regions in |
e9174d1e | 54 | /// the event of shadowing. |
e74abb32 | 55 | BrNamed(DefId, Symbol), |
e9174d1e | 56 | |
7cac9316 XL |
57 | /// Anonymous region for the implicit env pointer parameter |
58 | /// to a closure | |
cc61c64b | 59 | BrEnv, |
e9174d1e SL |
60 | } |
61 | ||
fc512014 XL |
62 | #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, PartialOrd, Ord)] |
63 | #[derive(HashStable)] | |
64 | pub struct BoundRegion { | |
65 | pub kind: BoundRegionKind, | |
66 | } | |
a1dfa0c6 | 67 | |
fc512014 | 68 | impl BoundRegion { |
a1dfa0c6 XL |
69 | /// When canonicalizing, we replace unbound inference variables and free |
70 | /// regions with anonymous late bound regions. This method asserts that | |
71 | /// we have an anonymous late bound region, which hence may refer to | |
72 | /// a canonical variable. | |
73 | pub fn assert_bound_var(&self) -> BoundVar { | |
fc512014 XL |
74 | match self.kind { |
75 | BoundRegionKind::BrAnon(var) => BoundVar::from_u32(var), | |
a1dfa0c6 XL |
76 | _ => bug!("bound region is not anonymous"), |
77 | } | |
78 | } | |
7cac9316 XL |
79 | } |
80 | ||
fc512014 XL |
81 | impl BoundRegionKind { |
82 | pub fn is_named(&self) -> bool { | |
83 | match *self { | |
84 | BoundRegionKind::BrNamed(_, name) => name != kw::UnderscoreLifetime, | |
85 | _ => false, | |
86 | } | |
87 | } | |
88 | } | |
89 | ||
90 | /// Defines the kinds of types. | |
91 | /// | |
0731742a | 92 | /// N.B., if you change this, you'll probably want to change the corresponding |
74b04a01 | 93 | /// AST structure in `librustc_ast/ast.rs` as well. |
3dfed10e | 94 | #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable, Debug)] |
ba9703b0 | 95 | #[derive(HashStable)] |
e74abb32 | 96 | #[rustc_diagnostic_item = "TyKind"] |
b7449926 | 97 | pub enum TyKind<'tcx> { |
e9174d1e | 98 | /// The primitive boolean type. Written as `bool`. |
b7449926 | 99 | Bool, |
e9174d1e SL |
100 | |
101 | /// The primitive character type; holds a Unicode scalar value | |
9fa01778 | 102 | /// (a non-surrogate code point). Written as `char`. |
b7449926 | 103 | Char, |
e9174d1e SL |
104 | |
105 | /// A primitive signed integer type. For example, `i32`. | |
5869c6ff | 106 | Int(ty::IntTy), |
e9174d1e SL |
107 | |
108 | /// A primitive unsigned integer type. For example, `u32`. | |
5869c6ff | 109 | Uint(ty::UintTy), |
e9174d1e SL |
110 | |
111 | /// A primitive floating-point type. For example, `f64`. | |
5869c6ff | 112 | Float(ty::FloatTy), |
e9174d1e | 113 | |
fc512014 | 114 | /// Algebraic data types (ADT). For example: structures, enumerations and unions. |
e9174d1e | 115 | /// |
532ac7d7 | 116 | /// InternalSubsts here, possibly against intuition, *may* contain `Param`s. |
e9174d1e | 117 | /// That is, even after substitution it is possible that there are type |
b7449926 | 118 | /// variables. This happens when the `Adt` corresponds to an ADT |
9e0c209e | 119 | /// definition and not a concrete use of it. |
532ac7d7 | 120 | Adt(&'tcx AdtDef, SubstsRef<'tcx>), |
e9174d1e | 121 | |
9fa01778 | 122 | /// An unsized FFI type that is opaque to Rust. Written as `extern type T`. |
b7449926 | 123 | Foreign(DefId), |
abe05a73 | 124 | |
e9174d1e | 125 | /// The pointee of a string slice. Written as `str`. |
b7449926 | 126 | Str, |
e9174d1e SL |
127 | |
128 | /// An array with the given length. Written as `[T; n]`. | |
532ac7d7 | 129 | Array(Ty<'tcx>, &'tcx ty::Const<'tcx>), |
e9174d1e | 130 | |
9fa01778 | 131 | /// The pointee of an array slice. Written as `[T]`. |
b7449926 | 132 | Slice(Ty<'tcx>), |
e9174d1e SL |
133 | |
134 | /// A raw pointer. Written as `*mut T` or `*const T` | |
b7449926 | 135 | RawPtr(TypeAndMut<'tcx>), |
e9174d1e SL |
136 | |
137 | /// A reference; a pointer with an associated lifetime. Written as | |
32a655c1 | 138 | /// `&'a mut T` or `&'a T`. |
b7449926 | 139 | Ref(Region<'tcx>, Ty<'tcx>, hir::Mutability), |
e9174d1e | 140 | |
54a0048b | 141 | /// The anonymous type of a function declaration/definition. Each |
0bf4aa26 XL |
142 | /// function has a unique type, which is output (for a function |
143 | /// named `foo` returning an `i32`) as `fn() -> i32 {foo}`. | |
144 | /// | |
145 | /// For example the type of `bar` here: | |
146 | /// | |
147 | /// ```rust | |
148 | /// fn foo() -> i32 { 1 } | |
149 | /// let bar = foo; // bar: fn() -> i32 {foo} | |
150 | /// ``` | |
532ac7d7 | 151 | FnDef(DefId, SubstsRef<'tcx>), |
54a0048b | 152 | |
9fa01778 | 153 | /// A pointer to a function. Written as `fn() -> i32`. |
0bf4aa26 XL |
154 | /// |
155 | /// For example the type of `bar` here: | |
156 | /// | |
157 | /// ```rust | |
158 | /// fn foo() -> i32 { 1 } | |
159 | /// let bar: fn() -> i32 = foo; | |
160 | /// ``` | |
b7449926 | 161 | FnPtr(PolyFnSig<'tcx>), |
e9174d1e SL |
162 | |
163 | /// A trait, defined with `trait`. | |
fc512014 | 164 | Dynamic(&'tcx List<Binder<ExistentialPredicate<'tcx>>>, ty::Region<'tcx>), |
e9174d1e SL |
165 | |
166 | /// The anonymous type of a closure. Used to represent the type of | |
167 | /// `|a| a`. | |
e74abb32 | 168 | Closure(DefId, SubstsRef<'tcx>), |
e9174d1e | 169 | |
ea8adc8c XL |
170 | /// The anonymous type of a generator. Used to represent the type of |
171 | /// `|a| yield a`. | |
60c5eb7d | 172 | Generator(DefId, SubstsRef<'tcx>, hir::Movability), |
ea8adc8c | 173 | |
fc512014 | 174 | /// A type representing the types stored inside a generator. |
2c00a5a8 | 175 | /// This should only appear in GeneratorInteriors. |
b7449926 | 176 | GeneratorWitness(Binder<&'tcx List<Ty<'tcx>>>), |
2c00a5a8 | 177 | |
fc512014 | 178 | /// The never type `!`. |
b7449926 | 179 | Never, |
5bcae85e | 180 | |
9fa01778 | 181 | /// A tuple type. For example, `(i32, bool)`. |
416331ca | 182 | /// Use `TyS::tuple_fields` to iterate over the field types. |
48663c56 | 183 | Tuple(SubstsRef<'tcx>), |
e9174d1e | 184 | |
9fa01778 | 185 | /// The projection of an associated type. For example, |
e9174d1e | 186 | /// `<T as Trait<..>>::N`. |
b7449926 | 187 | Projection(ProjectionTy<'tcx>), |
e9174d1e | 188 | |
b7449926 | 189 | /// Opaque (`impl Trait`) type found in a return type. |
0bf4aa26 | 190 | /// The `DefId` comes either from |
8faf50e0 | 191 | /// * the `impl Trait` ast::Ty node, |
416331ca | 192 | /// * or the `type Foo = impl Trait` declaration |
8faf50e0 | 193 | /// The substitutions are for the generics of the function in question. |
476ff2be | 194 | /// After typeck, the concrete type can be found in the `types` map. |
532ac7d7 | 195 | Opaque(DefId, SubstsRef<'tcx>), |
5bcae85e | 196 | |
3dfed10e | 197 | /// A type parameter; for example, `T` in `fn f<T>(x: T) {}`. |
b7449926 | 198 | Param(ParamTy), |
e9174d1e | 199 | |
a1dfa0c6 XL |
200 | /// Bound type variable, used only when preparing a trait query. |
201 | Bound(ty::DebruijnIndex, BoundTy), | |
202 | ||
203 | /// A placeholder type - universally quantified higher-ranked type. | |
204 | Placeholder(ty::PlaceholderType), | |
205 | ||
0bf4aa26 | 206 | /// A type variable used during type checking. |
b7449926 | 207 | Infer(InferTy), |
e9174d1e SL |
208 | |
209 | /// A placeholder for a type which could not be computed; this is | |
210 | /// propagated to avoid useless error messages. | |
f035d41b | 211 | Error(DelaySpanBugEmitted), |
e9174d1e SL |
212 | } |
213 | ||
3dfed10e XL |
214 | impl TyKind<'tcx> { |
215 | #[inline] | |
216 | pub fn is_primitive(&self) -> bool { | |
fc512014 | 217 | matches!(self, Bool | Char | Int(_) | Uint(_) | Float(_)) |
3dfed10e | 218 | } |
29967ef6 XL |
219 | |
220 | /// Get the article ("a" or "an") to use with this type. | |
221 | pub fn article(&self) -> &'static str { | |
222 | match self { | |
223 | Int(_) | Float(_) | Array(_, _) => "an", | |
224 | Adt(def, _) if def.is_enum() => "an", | |
225 | // This should never happen, but ICEing and causing the user's code | |
226 | // to not compile felt too harsh. | |
227 | Error(_) => "a", | |
228 | _ => "a", | |
229 | } | |
230 | } | |
3dfed10e | 231 | } |
f035d41b | 232 | |
a1dfa0c6 | 233 | // `TyKind` is used a lot. Make sure it doesn't unintentionally get bigger. |
6a06907d | 234 | #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] |
48663c56 | 235 | static_assert_size!(TyKind<'_>, 24); |
a1dfa0c6 | 236 | |
e9174d1e SL |
237 | /// A closure can be modeled as a struct that looks like: |
238 | /// | |
ba9703b0 | 239 | /// struct Closure<'l0...'li, T0...Tj, CK, CS, U>(...U); |
e9174d1e | 240 | /// |
ff7c6d11 XL |
241 | /// where: |
242 | /// | |
ba9703b0 | 243 | /// - 'l0...'li and T0...Tj are the generic parameters |
ff7c6d11 XL |
244 | /// in scope on the function that defined the closure, |
245 | /// - CK represents the *closure kind* (Fn vs FnMut vs FnOnce). This | |
246 | /// is rather hackily encoded via a scalar type. See | |
247 | /// `TyS::to_opt_closure_kind` for details. | |
248 | /// - CS represents the *closure signature*, representing as a `fn()` | |
249 | /// type. For example, `fn(u32, u32) -> u32` would mean that the closure | |
250 | /// implements `CK<(u32, u32), Output = u32>`, where `CK` is the trait | |
251 | /// specified above. | |
ba9703b0 XL |
252 | /// - U is a type parameter representing the types of its upvars, tupled up |
253 | /// (borrowed, if appropriate; that is, if an U field represents a by-ref upvar, | |
254 | /// and the up-var has the type `Foo`, then that field of U will be `&Foo`). | |
e9174d1e SL |
255 | /// |
256 | /// So, for example, given this function: | |
257 | /// | |
258 | /// fn foo<'a, T>(data: &'a mut T) { | |
259 | /// do(|| data.count += 1) | |
260 | /// } | |
261 | /// | |
262 | /// the type of the closure would be something like: | |
263 | /// | |
ba9703b0 | 264 | /// struct Closure<'a, T, U>(...U); |
e9174d1e SL |
265 | /// |
266 | /// Note that the type of the upvar is not specified in the struct. | |
267 | /// You may wonder how the impl would then be able to use the upvar, | |
268 | /// if it doesn't know it's type? The answer is that the impl is | |
269 | /// (conceptually) not fully generic over Closure but rather tied to | |
270 | /// instances with the expected upvar types: | |
271 | /// | |
ba9703b0 | 272 | /// impl<'b, 'a, T> FnMut() for Closure<'a, T, (&'b mut &'a mut T,)> { |
e9174d1e SL |
273 | /// ... |
274 | /// } | |
275 | /// | |
276 | /// You can see that the *impl* fully specified the type of the upvar | |
277 | /// and thus knows full well that `data` has type `&'b mut &'a mut T`. | |
278 | /// (Here, I am assuming that `data` is mut-borrowed.) | |
279 | /// | |
280 | /// Now, the last question you may ask is: Why include the upvar types | |
ba9703b0 | 281 | /// in an extra type parameter? The reason for this design is that the |
e9174d1e SL |
282 | /// upvar types can reference lifetimes that are internal to the |
283 | /// creating function. In my example above, for example, the lifetime | |
ea8adc8c XL |
284 | /// `'b` represents the scope of the closure itself; this is some |
285 | /// subset of `foo`, probably just the scope of the call to the to | |
e9174d1e SL |
286 | /// `do()`. If we just had the lifetime/type parameters from the |
287 | /// enclosing function, we couldn't name this lifetime `'b`. Note that | |
288 | /// there can also be lifetimes in the types of the upvars themselves, | |
289 | /// if one of them happens to be a reference to something that the | |
290 | /// creating fn owns. | |
291 | /// | |
292 | /// OK, you say, so why not create a more minimal set of parameters | |
293 | /// that just includes the extra lifetime parameters? The answer is | |
294 | /// primarily that it would be hard --- we don't know at the time when | |
295 | /// we create the closure type what the full types of the upvars are, | |
296 | /// nor do we know which are borrowed and which are not. In this | |
297 | /// design, we can just supply a fresh type parameter and figure that | |
298 | /// out later. | |
299 | /// | |
300 | /// All right, you say, but why include the type parameters from the | |
94b46f34 | 301 | /// original function then? The answer is that codegen may need them |
9fa01778 | 302 | /// when monomorphizing, and they may not appear in the upvars. A |
e9174d1e SL |
303 | /// closure could capture no variables but still make use of some |
304 | /// in-scope type parameter with a bound (e.g., if our example above | |
305 | /// had an extra `U: Default`, and the closure called `U::default()`). | |
306 | /// | |
307 | /// There is another reason. This design (implicitly) prohibits | |
308 | /// closures from capturing themselves (except via a trait | |
309 | /// object). This simplifies closure inference considerably, since it | |
310 | /// means that when we infer the kind of a closure or its upvars, we | |
311 | /// don't have to handle cycles where the decisions we make for | |
312 | /// closure C wind up influencing the decisions we ought to make for | |
313 | /// closure C (which would then require fixed point iteration to | |
314 | /// handle). Plus it fixes an ICE. :P | |
ff7c6d11 XL |
315 | /// |
316 | /// ## Generators | |
317 | /// | |
48663c56 | 318 | /// Generators are handled similarly in `GeneratorSubsts`. The set of |
74b04a01 XL |
319 | /// type parameters is similar, but `CK` and `CS` are replaced by the |
320 | /// following type parameters: | |
321 | /// | |
322 | /// * `GS`: The generator's "resume type", which is the type of the | |
323 | /// argument passed to `resume`, and the type of `yield` expressions | |
324 | /// inside the generator. | |
325 | /// * `GY`: The "yield type", which is the type of values passed to | |
326 | /// `yield` inside the generator. | |
327 | /// * `GR`: The "return type", which is the type of value returned upon | |
328 | /// completion of the generator. | |
329 | /// * `GW`: The "generator witness". | |
60c5eb7d | 330 | #[derive(Copy, Clone, Debug, TypeFoldable)] |
e9174d1e | 331 | pub struct ClosureSubsts<'tcx> { |
476ff2be | 332 | /// Lifetime and type parameters from the enclosing function, |
ba9703b0 | 333 | /// concatenated with a tuple containing the types of the upvars. |
476ff2be | 334 | /// |
94b46f34 | 335 | /// These are separated out because codegen wants to pass them around |
e9174d1e | 336 | /// when monomorphizing. |
532ac7d7 | 337 | pub substs: SubstsRef<'tcx>, |
476ff2be | 338 | } |
e9174d1e | 339 | |
3dfed10e XL |
340 | /// Struct returned by `split()`. |
341 | pub struct ClosureSubstsParts<'tcx, T> { | |
342 | pub parent_substs: &'tcx [GenericArg<'tcx>], | |
343 | pub closure_kind_ty: T, | |
344 | pub closure_sig_as_fn_ptr_ty: T, | |
345 | pub tupled_upvars_ty: T, | |
ff7c6d11 XL |
346 | } |
347 | ||
348 | impl<'tcx> ClosureSubsts<'tcx> { | |
3dfed10e XL |
349 | /// Construct `ClosureSubsts` from `ClosureSubstsParts`, containing `Substs` |
350 | /// for the closure parent, alongside additional closure-specific components. | |
351 | pub fn new( | |
352 | tcx: TyCtxt<'tcx>, | |
353 | parts: ClosureSubstsParts<'tcx, Ty<'tcx>>, | |
354 | ) -> ClosureSubsts<'tcx> { | |
355 | ClosureSubsts { | |
356 | substs: tcx.mk_substs( | |
357 | parts.parent_substs.iter().copied().chain( | |
358 | [parts.closure_kind_ty, parts.closure_sig_as_fn_ptr_ty, parts.tupled_upvars_ty] | |
359 | .iter() | |
360 | .map(|&ty| ty.into()), | |
361 | ), | |
362 | ), | |
363 | } | |
364 | } | |
365 | ||
366 | /// Divides the closure substs into their respective components. | |
367 | /// The ordering assumed here must match that used by `ClosureSubsts::new` above. | |
368 | fn split(self) -> ClosureSubstsParts<'tcx, GenericArg<'tcx>> { | |
ba9703b0 | 369 | match self.substs[..] { |
3dfed10e XL |
370 | [ref parent_substs @ .., closure_kind_ty, closure_sig_as_fn_ptr_ty, tupled_upvars_ty] => { |
371 | ClosureSubstsParts { | |
372 | parent_substs, | |
373 | closure_kind_ty, | |
374 | closure_sig_as_fn_ptr_ty, | |
375 | tupled_upvars_ty, | |
376 | } | |
ba9703b0 XL |
377 | } |
378 | _ => bug!("closure substs missing synthetics"), | |
ff7c6d11 XL |
379 | } |
380 | } | |
381 | ||
ba9703b0 XL |
382 | /// Returns `true` only if enough of the synthetic types are known to |
383 | /// allow using all of the methods on `ClosureSubsts` without panicking. | |
384 | /// | |
385 | /// Used primarily by `ty::print::pretty` to be able to handle closure | |
386 | /// types that haven't had their synthetic types substituted in. | |
387 | pub fn is_valid(self) -> bool { | |
1b1a35ee XL |
388 | self.substs.len() >= 3 |
389 | && matches!(self.split().tupled_upvars_ty.expect_ty().kind(), Tuple(_)) | |
ba9703b0 XL |
390 | } |
391 | ||
3dfed10e XL |
392 | /// Returns the substitutions of the closure's parent. |
393 | pub fn parent_substs(self) -> &'tcx [GenericArg<'tcx>] { | |
394 | self.split().parent_substs | |
395 | } | |
396 | ||
29967ef6 XL |
397 | /// Returns an iterator over the list of types of captured paths by the closure. |
398 | /// In case there was a type error in figuring out the types of the captured path, an | |
399 | /// empty iterator is returned. | |
476ff2be | 400 | #[inline] |
ba9703b0 | 401 | pub fn upvar_tys(self) -> impl Iterator<Item = Ty<'tcx>> + 'tcx { |
29967ef6 XL |
402 | match self.tupled_upvars_ty().kind() { |
403 | TyKind::Error(_) => None, | |
404 | TyKind::Tuple(..) => Some(self.tupled_upvars_ty().tuple_fields()), | |
405 | TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"), | |
406 | ty => bug!("Unexpected representation of upvar types tuple {:?}", ty), | |
407 | } | |
408 | .into_iter() | |
409 | .flatten() | |
3dfed10e XL |
410 | } |
411 | ||
412 | /// Returns the tuple type representing the upvars for this closure. | |
413 | #[inline] | |
414 | pub fn tupled_upvars_ty(self) -> Ty<'tcx> { | |
415 | self.split().tupled_upvars_ty.expect_ty() | |
ff7c6d11 XL |
416 | } |
417 | ||
418 | /// Returns the closure kind for this closure; may return a type | |
419 | /// variable during inference. To get the closure kind during | |
ba9703b0 XL |
420 | /// inference, use `infcx.closure_kind(substs)`. |
421 | pub fn kind_ty(self) -> Ty<'tcx> { | |
422 | self.split().closure_kind_ty.expect_ty() | |
ff7c6d11 XL |
423 | } |
424 | ||
ba9703b0 XL |
425 | /// Returns the `fn` pointer type representing the closure signature for this |
426 | /// closure. | |
427 | // FIXME(eddyb) this should be unnecessary, as the shallowly resolved | |
428 | // type is known at the time of the creation of `ClosureSubsts`, | |
429 | // see `rustc_typeck::check::closure`. | |
430 | pub fn sig_as_fn_ptr_ty(self) -> Ty<'tcx> { | |
431 | self.split().closure_sig_as_fn_ptr_ty.expect_ty() | |
ff7c6d11 XL |
432 | } |
433 | ||
ff7c6d11 XL |
434 | /// Returns the closure kind for this closure; only usable outside |
435 | /// of an inference context, because in that context we know that | |
436 | /// there are no type variables. | |
437 | /// | |
438 | /// If you have an inference context, use `infcx.closure_kind()`. | |
ba9703b0 XL |
439 | pub fn kind(self) -> ty::ClosureKind { |
440 | self.kind_ty().to_opt_closure_kind().unwrap() | |
ff7c6d11 XL |
441 | } |
442 | ||
ba9703b0 XL |
443 | /// Extracts the signature from the closure. |
444 | pub fn sig(self) -> ty::PolyFnSig<'tcx> { | |
445 | let ty = self.sig_as_fn_ptr_ty(); | |
1b1a35ee XL |
446 | match ty.kind() { |
447 | ty::FnPtr(sig) => *sig, | |
448 | _ => bug!("closure_sig_as_fn_ptr_ty is not a fn-ptr: {:?}", ty.kind()), | |
ff7c6d11 | 449 | } |
476ff2be | 450 | } |
a7813a04 | 451 | } |
9cc50fc6 | 452 | |
48663c56 | 453 | /// Similar to `ClosureSubsts`; see the above documentation for more. |
60c5eb7d | 454 | #[derive(Copy, Clone, Debug, TypeFoldable)] |
94b46f34 | 455 | pub struct GeneratorSubsts<'tcx> { |
532ac7d7 | 456 | pub substs: SubstsRef<'tcx>, |
94b46f34 XL |
457 | } |
458 | ||
3dfed10e XL |
459 | pub struct GeneratorSubstsParts<'tcx, T> { |
460 | pub parent_substs: &'tcx [GenericArg<'tcx>], | |
461 | pub resume_ty: T, | |
462 | pub yield_ty: T, | |
463 | pub return_ty: T, | |
464 | pub witness: T, | |
465 | pub tupled_upvars_ty: T, | |
94b46f34 XL |
466 | } |
467 | ||
468 | impl<'tcx> GeneratorSubsts<'tcx> { | |
3dfed10e XL |
469 | /// Construct `GeneratorSubsts` from `GeneratorSubstsParts`, containing `Substs` |
470 | /// for the generator parent, alongside additional generator-specific components. | |
471 | pub fn new( | |
472 | tcx: TyCtxt<'tcx>, | |
473 | parts: GeneratorSubstsParts<'tcx, Ty<'tcx>>, | |
474 | ) -> GeneratorSubsts<'tcx> { | |
475 | GeneratorSubsts { | |
476 | substs: tcx.mk_substs( | |
477 | parts.parent_substs.iter().copied().chain( | |
478 | [ | |
479 | parts.resume_ty, | |
480 | parts.yield_ty, | |
481 | parts.return_ty, | |
482 | parts.witness, | |
483 | parts.tupled_upvars_ty, | |
484 | ] | |
485 | .iter() | |
486 | .map(|&ty| ty.into()), | |
487 | ), | |
488 | ), | |
489 | } | |
490 | } | |
491 | ||
492 | /// Divides the generator substs into their respective components. | |
493 | /// The ordering assumed here must match that used by `GeneratorSubsts::new` above. | |
494 | fn split(self) -> GeneratorSubstsParts<'tcx, GenericArg<'tcx>> { | |
ba9703b0 | 495 | match self.substs[..] { |
3dfed10e XL |
496 | [ref parent_substs @ .., resume_ty, yield_ty, return_ty, witness, tupled_upvars_ty] => { |
497 | GeneratorSubstsParts { | |
498 | parent_substs, | |
499 | resume_ty, | |
500 | yield_ty, | |
501 | return_ty, | |
502 | witness, | |
503 | tupled_upvars_ty, | |
504 | } | |
ba9703b0 XL |
505 | } |
506 | _ => bug!("generator substs missing synthetics"), | |
94b46f34 XL |
507 | } |
508 | } | |
509 | ||
ba9703b0 XL |
510 | /// Returns `true` only if enough of the synthetic types are known to |
511 | /// allow using all of the methods on `GeneratorSubsts` without panicking. | |
512 | /// | |
513 | /// Used primarily by `ty::print::pretty` to be able to handle generator | |
514 | /// types that haven't had their synthetic types substituted in. | |
515 | pub fn is_valid(self) -> bool { | |
1b1a35ee XL |
516 | self.substs.len() >= 5 |
517 | && matches!(self.split().tupled_upvars_ty.expect_ty().kind(), Tuple(_)) | |
ba9703b0 XL |
518 | } |
519 | ||
3dfed10e XL |
520 | /// Returns the substitutions of the generator's parent. |
521 | pub fn parent_substs(self) -> &'tcx [GenericArg<'tcx>] { | |
522 | self.split().parent_substs | |
523 | } | |
524 | ||
94b46f34 XL |
525 | /// This describes the types that can be contained in a generator. |
526 | /// It will be a type variable initially and unified in the last stages of typeck of a body. | |
527 | /// It contains a tuple of all the types that could end up on a generator frame. | |
528 | /// The state transformation MIR pass may only produce layouts which mention types | |
529 | /// in this tuple. Upvars are not counted here. | |
ba9703b0 XL |
530 | pub fn witness(self) -> Ty<'tcx> { |
531 | self.split().witness.expect_ty() | |
94b46f34 XL |
532 | } |
533 | ||
29967ef6 XL |
534 | /// Returns an iterator over the list of types of captured paths by the generator. |
535 | /// In case there was a type error in figuring out the types of the captured path, an | |
536 | /// empty iterator is returned. | |
94b46f34 | 537 | #[inline] |
ba9703b0 | 538 | pub fn upvar_tys(self) -> impl Iterator<Item = Ty<'tcx>> + 'tcx { |
29967ef6 XL |
539 | match self.tupled_upvars_ty().kind() { |
540 | TyKind::Error(_) => None, | |
541 | TyKind::Tuple(..) => Some(self.tupled_upvars_ty().tuple_fields()), | |
542 | TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"), | |
543 | ty => bug!("Unexpected representation of upvar types tuple {:?}", ty), | |
544 | } | |
545 | .into_iter() | |
546 | .flatten() | |
3dfed10e XL |
547 | } |
548 | ||
549 | /// Returns the tuple type representing the upvars for this generator. | |
550 | #[inline] | |
551 | pub fn tupled_upvars_ty(self) -> Ty<'tcx> { | |
552 | self.split().tupled_upvars_ty.expect_ty() | |
94b46f34 XL |
553 | } |
554 | ||
74b04a01 | 555 | /// Returns the type representing the resume type of the generator. |
ba9703b0 XL |
556 | pub fn resume_ty(self) -> Ty<'tcx> { |
557 | self.split().resume_ty.expect_ty() | |
74b04a01 XL |
558 | } |
559 | ||
94b46f34 | 560 | /// Returns the type representing the yield type of the generator. |
ba9703b0 XL |
561 | pub fn yield_ty(self) -> Ty<'tcx> { |
562 | self.split().yield_ty.expect_ty() | |
94b46f34 XL |
563 | } |
564 | ||
565 | /// Returns the type representing the return type of the generator. | |
ba9703b0 XL |
566 | pub fn return_ty(self) -> Ty<'tcx> { |
567 | self.split().return_ty.expect_ty() | |
94b46f34 XL |
568 | } |
569 | ||
9fa01778 | 570 | /// Returns the "generator signature", which consists of its yield |
94b46f34 XL |
571 | /// and return types. |
572 | /// | |
9fa01778 | 573 | /// N.B., some bits of the code prefers to see this wrapped in a |
94b46f34 XL |
574 | /// binder, but it never contains bound regions. Probably this |
575 | /// function should be removed. | |
ba9703b0 XL |
576 | pub fn poly_sig(self) -> PolyGenSig<'tcx> { |
577 | ty::Binder::dummy(self.sig()) | |
94b46f34 XL |
578 | } |
579 | ||
74b04a01 | 580 | /// Returns the "generator signature", which consists of its resume, yield |
94b46f34 | 581 | /// and return types. |
ba9703b0 | 582 | pub fn sig(self) -> GenSig<'tcx> { |
74b04a01 | 583 | ty::GenSig { |
ba9703b0 XL |
584 | resume_ty: self.resume_ty(), |
585 | yield_ty: self.yield_ty(), | |
586 | return_ty: self.return_ty(), | |
74b04a01 | 587 | } |
94b46f34 XL |
588 | } |
589 | } | |
590 | ||
dc9dc135 | 591 | impl<'tcx> GeneratorSubsts<'tcx> { |
60c5eb7d | 592 | /// Generator has not been resumed yet. |
48663c56 | 593 | pub const UNRESUMED: usize = 0; |
60c5eb7d | 594 | /// Generator has returned or is completed. |
48663c56 | 595 | pub const RETURNED: usize = 1; |
60c5eb7d | 596 | /// Generator has been poisoned. |
48663c56 XL |
597 | pub const POISONED: usize = 2; |
598 | ||
599 | const UNRESUMED_NAME: &'static str = "Unresumed"; | |
600 | const RETURNED_NAME: &'static str = "Returned"; | |
601 | const POISONED_NAME: &'static str = "Panicked"; | |
602 | ||
60c5eb7d | 603 | /// The valid variant indices of this generator. |
48663c56 | 604 | #[inline] |
dc9dc135 | 605 | pub fn variant_range(&self, def_id: DefId, tcx: TyCtxt<'tcx>) -> Range<VariantIdx> { |
48663c56 | 606 | // FIXME requires optimized MIR |
5869c6ff | 607 | let num_variants = tcx.generator_layout(def_id).unwrap().variant_fields.len(); |
dfeec247 | 608 | VariantIdx::new(0)..VariantIdx::new(num_variants) |
48663c56 XL |
609 | } |
610 | ||
60c5eb7d | 611 | /// The discriminant for the given variant. Panics if the `variant_index` is |
48663c56 XL |
612 | /// out of range. |
613 | #[inline] | |
614 | pub fn discriminant_for_variant( | |
dc9dc135 XL |
615 | &self, |
616 | def_id: DefId, | |
617 | tcx: TyCtxt<'tcx>, | |
618 | variant_index: VariantIdx, | |
48663c56 XL |
619 | ) -> Discr<'tcx> { |
620 | // Generators don't support explicit discriminant values, so they are | |
621 | // the same as the variant index. | |
622 | assert!(self.variant_range(def_id, tcx).contains(&variant_index)); | |
623 | Discr { val: variant_index.as_usize() as u128, ty: self.discr_ty(tcx) } | |
624 | } | |
625 | ||
60c5eb7d | 626 | /// The set of all discriminants for the generator, enumerated with their |
48663c56 XL |
627 | /// variant indices. |
628 | #[inline] | |
629 | pub fn discriminants( | |
e74abb32 | 630 | self, |
dc9dc135 XL |
631 | def_id: DefId, |
632 | tcx: TyCtxt<'tcx>, | |
633 | ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> { | |
48663c56 XL |
634 | self.variant_range(def_id, tcx).map(move |index| { |
635 | (index, Discr { val: index.as_usize() as u128, ty: self.discr_ty(tcx) }) | |
636 | }) | |
637 | } | |
638 | ||
639 | /// Calls `f` with a reference to the name of the enumerator for the given | |
640 | /// variant `v`. | |
f035d41b | 641 | pub fn variant_name(v: VariantIdx) -> Cow<'static, str> { |
48663c56 XL |
642 | match v.as_usize() { |
643 | Self::UNRESUMED => Cow::from(Self::UNRESUMED_NAME), | |
644 | Self::RETURNED => Cow::from(Self::RETURNED_NAME), | |
645 | Self::POISONED => Cow::from(Self::POISONED_NAME), | |
dfeec247 | 646 | _ => Cow::from(format!("Suspend{}", v.as_usize() - 3)), |
48663c56 XL |
647 | } |
648 | } | |
649 | ||
650 | /// The type of the state discriminant used in the generator type. | |
651 | #[inline] | |
dc9dc135 | 652 | pub fn discr_ty(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
48663c56 XL |
653 | tcx.types.u32 |
654 | } | |
655 | ||
ea8adc8c XL |
656 | /// This returns the types of the MIR locals which had to be stored across suspension points. |
657 | /// It is calculated in rustc_mir::transform::generator::StateTransform. | |
658 | /// All the types here must be in the tuple in GeneratorInterior. | |
48663c56 XL |
659 | /// |
660 | /// The locals are grouped by their variant number. Note that some locals may | |
661 | /// be repeated in multiple variants. | |
662 | #[inline] | |
dc9dc135 XL |
663 | pub fn state_tys( |
664 | self, | |
665 | def_id: DefId, | |
666 | tcx: TyCtxt<'tcx>, | |
667 | ) -> impl Iterator<Item = impl Iterator<Item = Ty<'tcx>> + Captures<'tcx>> { | |
5869c6ff | 668 | let layout = tcx.generator_layout(def_id).unwrap(); |
48663c56 | 669 | layout.variant_fields.iter().map(move |variant| { |
dfeec247 | 670 | variant.iter().map(move |field| layout.field_tys[*field].subst(tcx, self.substs)) |
48663c56 | 671 | }) |
2c00a5a8 XL |
672 | } |
673 | ||
48663c56 XL |
674 | /// This is the types of the fields of a generator which are not stored in a |
675 | /// variant. | |
676 | #[inline] | |
ba9703b0 XL |
677 | pub fn prefix_tys(self) -> impl Iterator<Item = Ty<'tcx>> { |
678 | self.upvar_tys() | |
ea8adc8c XL |
679 | } |
680 | } | |
681 | ||
94b46f34 XL |
682 | #[derive(Debug, Copy, Clone)] |
683 | pub enum UpvarSubsts<'tcx> { | |
e74abb32 XL |
684 | Closure(SubstsRef<'tcx>), |
685 | Generator(SubstsRef<'tcx>), | |
94b46f34 XL |
686 | } |
687 | ||
688 | impl<'tcx> UpvarSubsts<'tcx> { | |
29967ef6 XL |
689 | /// Returns an iterator over the list of types of captured paths by the closure/generator. |
690 | /// In case there was a type error in figuring out the types of the captured path, an | |
691 | /// empty iterator is returned. | |
94b46f34 | 692 | #[inline] |
ba9703b0 | 693 | pub fn upvar_tys(self) -> impl Iterator<Item = Ty<'tcx>> + 'tcx { |
29967ef6 XL |
694 | let tupled_tys = match self { |
695 | UpvarSubsts::Closure(substs) => substs.as_closure().tupled_upvars_ty(), | |
696 | UpvarSubsts::Generator(substs) => substs.as_generator().tupled_upvars_ty(), | |
94b46f34 | 697 | }; |
29967ef6 XL |
698 | |
699 | match tupled_tys.kind() { | |
700 | TyKind::Error(_) => None, | |
701 | TyKind::Tuple(..) => Some(self.tupled_upvars_ty().tuple_fields()), | |
702 | TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"), | |
703 | ty => bug!("Unexpected representation of upvar types tuple {:?}", ty), | |
704 | } | |
705 | .into_iter() | |
706 | .flatten() | |
707 | } | |
708 | ||
709 | #[inline] | |
710 | pub fn tupled_upvars_ty(self) -> Ty<'tcx> { | |
711 | match self { | |
712 | UpvarSubsts::Closure(substs) => substs.as_closure().tupled_upvars_ty(), | |
713 | UpvarSubsts::Generator(substs) => substs.as_generator().tupled_upvars_ty(), | |
714 | } | |
94b46f34 | 715 | } |
ea8adc8c XL |
716 | } |
717 | ||
3dfed10e | 718 | #[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Ord, Eq, Hash, TyEncodable, TyDecodable)] |
60c5eb7d | 719 | #[derive(HashStable, TypeFoldable)] |
476ff2be | 720 | pub enum ExistentialPredicate<'tcx> { |
9fa01778 | 721 | /// E.g., `Iterator`. |
476ff2be | 722 | Trait(ExistentialTraitRef<'tcx>), |
9fa01778 | 723 | /// E.g., `Iterator::Item = T`. |
476ff2be | 724 | Projection(ExistentialProjection<'tcx>), |
9fa01778 | 725 | /// E.g., `Send`. |
476ff2be SL |
726 | AutoTrait(DefId), |
727 | } | |
728 | ||
dc9dc135 | 729 | impl<'tcx> ExistentialPredicate<'tcx> { |
94b46f34 XL |
730 | /// Compares via an ordering that will not change if modules are reordered or other changes are |
731 | /// made to the tree. In particular, this ordering is preserved across incremental compilations. | |
dc9dc135 | 732 | pub fn stable_cmp(&self, tcx: TyCtxt<'tcx>, other: &Self) -> Ordering { |
476ff2be SL |
733 | use self::ExistentialPredicate::*; |
734 | match (*self, *other) { | |
735 | (Trait(_), Trait(_)) => Ordering::Equal, | |
dfeec247 XL |
736 | (Projection(ref a), Projection(ref b)) => { |
737 | tcx.def_path_hash(a.item_def_id).cmp(&tcx.def_path_hash(b.item_def_id)) | |
738 | } | |
739 | (AutoTrait(ref a), AutoTrait(ref b)) => { | |
740 | tcx.trait_def(*a).def_path_hash.cmp(&tcx.trait_def(*b).def_path_hash) | |
741 | } | |
476ff2be SL |
742 | (Trait(_), _) => Ordering::Less, |
743 | (Projection(_), Trait(_)) => Ordering::Greater, | |
744 | (Projection(_), _) => Ordering::Less, | |
745 | (AutoTrait(_), _) => Ordering::Greater, | |
746 | } | |
747 | } | |
476ff2be SL |
748 | } |
749 | ||
dc9dc135 XL |
750 | impl<'tcx> Binder<ExistentialPredicate<'tcx>> { |
751 | pub fn with_self_ty(&self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ty::Predicate<'tcx> { | |
9fa01778 | 752 | use crate::ty::ToPredicate; |
f035d41b | 753 | match self.skip_binder() { |
dfeec247 | 754 | ExistentialPredicate::Trait(tr) => { |
29967ef6 | 755 | self.rebind(tr).with_self_ty(tcx, self_ty).without_const().to_predicate(tcx) |
dfeec247 XL |
756 | } |
757 | ExistentialPredicate::Projection(p) => { | |
29967ef6 | 758 | self.rebind(p.with_self_ty(tcx, self_ty)).to_predicate(tcx) |
dfeec247 | 759 | } |
476ff2be | 760 | ExistentialPredicate::AutoTrait(did) => { |
29967ef6 XL |
761 | let trait_ref = self.rebind(ty::TraitRef { |
762 | def_id: did, | |
763 | substs: tcx.mk_substs_trait(self_ty, &[]), | |
764 | }); | |
f9f354fc | 765 | trait_ref.without_const().to_predicate(tcx) |
476ff2be SL |
766 | } |
767 | } | |
768 | } | |
769 | } | |
770 | ||
fc512014 | 771 | impl<'tcx> List<ty::Binder<ExistentialPredicate<'tcx>>> { |
e1599b0c | 772 | /// Returns the "principal `DefId`" of this set of existential predicates. |
0731742a XL |
773 | /// |
774 | /// A Rust trait object type consists (in addition to a lifetime bound) | |
775 | /// of a set of trait bounds, which are separated into any number | |
416331ca | 776 | /// of auto-trait bounds, and at most one non-auto-trait bound. The |
0731742a XL |
777 | /// non-auto-trait bound is called the "principal" of the trait |
778 | /// object. | |
779 | /// | |
780 | /// Only the principal can have methods or type parameters (because | |
781 | /// auto traits can have neither of them). This is important, because | |
782 | /// it means the auto traits can be treated as an unordered set (methods | |
783 | /// would force an order for the vtable, while relating traits with | |
784 | /// type parameters without knowing the order to relate them in is | |
785 | /// a rather non-trivial task). | |
786 | /// | |
787 | /// For example, in the trait object `dyn fmt::Debug + Sync`, the | |
788 | /// principal bound is `Some(fmt::Debug)`, while the auto-trait bounds | |
789 | /// are the set `{Sync}`. | |
790 | /// | |
791 | /// It is also possible to have a "trivial" trait object that | |
792 | /// consists only of auto traits, with no principal - for example, | |
793 | /// `dyn Send + Sync`. In that case, the set of auto-trait bounds | |
794 | /// is `{Send, Sync}`, while there is no principal. These trait objects | |
795 | /// have a "trivial" vtable consisting of just the size, alignment, | |
796 | /// and destructor. | |
fc512014 XL |
797 | pub fn principal(&self) -> Option<ty::Binder<ExistentialTraitRef<'tcx>>> { |
798 | self[0] | |
799 | .map_bound(|this| match this { | |
800 | ExistentialPredicate::Trait(tr) => Some(tr), | |
801 | _ => None, | |
802 | }) | |
803 | .transpose() | |
476ff2be SL |
804 | } |
805 | ||
0731742a | 806 | pub fn principal_def_id(&self) -> Option<DefId> { |
fc512014 | 807 | self.principal().map(|trait_ref| trait_ref.skip_binder().def_id) |
0731742a XL |
808 | } |
809 | ||
476ff2be | 810 | #[inline] |
dfeec247 XL |
811 | pub fn projection_bounds<'a>( |
812 | &'a self, | |
fc512014 XL |
813 | ) -> impl Iterator<Item = ty::Binder<ExistentialProjection<'tcx>>> + 'a { |
814 | self.iter().filter_map(|predicate| { | |
815 | predicate | |
816 | .map_bound(|pred| match pred { | |
817 | ExistentialPredicate::Projection(projection) => Some(projection), | |
818 | _ => None, | |
819 | }) | |
820 | .transpose() | |
476ff2be SL |
821 | }) |
822 | } | |
823 | ||
824 | #[inline] | |
416331ca | 825 | pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item = DefId> + 'a { |
fc512014 | 826 | self.iter().filter_map(|predicate| match predicate.skip_binder() { |
dfeec247 XL |
827 | ExistentialPredicate::AutoTrait(did) => Some(did), |
828 | _ => None, | |
476ff2be SL |
829 | }) |
830 | } | |
831 | } | |
832 | ||
e9174d1e | 833 | /// A complete reference to a trait. These take numerous guises in syntax, |
9fa01778 | 834 | /// but perhaps the most recognizable form is in a where-clause: |
e9174d1e | 835 | /// |
a1dfa0c6 | 836 | /// T: Foo<U> |
e9174d1e | 837 | /// |
9fa01778 XL |
838 | /// This would be represented by a trait-reference where the `DefId` is the |
839 | /// `DefId` for the trait `Foo` and the substs define `T` as parameter 0, | |
9e0c209e | 840 | /// and `U` as parameter 1. |
e9174d1e SL |
841 | /// |
842 | /// Trait references also appear in object types like `Foo<U>`, but in | |
843 | /// that case the `Self` parameter is absent from the substitutions. | |
3dfed10e | 844 | #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)] |
60c5eb7d | 845 | #[derive(HashStable, TypeFoldable)] |
e9174d1e SL |
846 | pub struct TraitRef<'tcx> { |
847 | pub def_id: DefId, | |
532ac7d7 | 848 | pub substs: SubstsRef<'tcx>, |
e9174d1e SL |
849 | } |
850 | ||
8bb4bdeb | 851 | impl<'tcx> TraitRef<'tcx> { |
532ac7d7 | 852 | pub fn new(def_id: DefId, substs: SubstsRef<'tcx>) -> TraitRef<'tcx> { |
60c5eb7d | 853 | TraitRef { def_id, substs } |
8bb4bdeb XL |
854 | } |
855 | ||
a1dfa0c6 | 856 | /// Returns a `TraitRef` of the form `P0: Foo<P1..Pn>` where `Pi` |
8faf50e0 | 857 | /// are the parameters defined on trait. |
dc9dc135 | 858 | pub fn identity(tcx: TyCtxt<'tcx>, def_id: DefId) -> TraitRef<'tcx> { |
dfeec247 | 859 | TraitRef { def_id, substs: InternalSubsts::identity_for_item(tcx, def_id) } |
8faf50e0 XL |
860 | } |
861 | ||
a1dfa0c6 | 862 | #[inline] |
8bb4bdeb XL |
863 | pub fn self_ty(&self) -> Ty<'tcx> { |
864 | self.substs.type_at(0) | |
865 | } | |
866 | ||
dc9dc135 XL |
867 | pub fn from_method( |
868 | tcx: TyCtxt<'tcx>, | |
869 | trait_id: DefId, | |
870 | substs: SubstsRef<'tcx>, | |
871 | ) -> ty::TraitRef<'tcx> { | |
94b46f34 XL |
872 | let defs = tcx.generics_of(trait_id); |
873 | ||
dfeec247 | 874 | ty::TraitRef { def_id: trait_id, substs: tcx.intern_substs(&substs[..defs.params.len()]) } |
94b46f34 | 875 | } |
8bb4bdeb XL |
876 | } |
877 | ||
e9174d1e SL |
878 | pub type PolyTraitRef<'tcx> = Binder<TraitRef<'tcx>>; |
879 | ||
880 | impl<'tcx> PolyTraitRef<'tcx> { | |
f035d41b XL |
881 | pub fn self_ty(&self) -> Binder<Ty<'tcx>> { |
882 | self.map_bound_ref(|tr| tr.self_ty()) | |
e9174d1e SL |
883 | } |
884 | ||
885 | pub fn def_id(&self) -> DefId { | |
83c7162d | 886 | self.skip_binder().def_id |
e9174d1e SL |
887 | } |
888 | ||
889 | pub fn to_poly_trait_predicate(&self) -> ty::PolyTraitPredicate<'tcx> { | |
29967ef6 | 890 | self.map_bound(|trait_ref| ty::TraitPredicate { trait_ref }) |
e9174d1e SL |
891 | } |
892 | } | |
893 | ||
9e0c209e SL |
894 | /// An existential reference to a trait, where `Self` is erased. |
895 | /// For example, the trait object `Trait<'a, 'b, X, Y>` is: | |
896 | /// | |
897 | /// exists T. T: Trait<'a, 'b, X, Y> | |
898 | /// | |
899 | /// The substitutions don't include the erased `Self`, only trait | |
900 | /// type and lifetime parameters (`[X, Y]` and `['a, 'b]` above). | |
3dfed10e | 901 | #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
60c5eb7d | 902 | #[derive(HashStable, TypeFoldable)] |
9e0c209e SL |
903 | pub struct ExistentialTraitRef<'tcx> { |
904 | pub def_id: DefId, | |
532ac7d7 | 905 | pub substs: SubstsRef<'tcx>, |
9e0c209e SL |
906 | } |
907 | ||
dc9dc135 | 908 | impl<'tcx> ExistentialTraitRef<'tcx> { |
dc9dc135 XL |
909 | pub fn erase_self_ty( |
910 | tcx: TyCtxt<'tcx>, | |
911 | trait_ref: ty::TraitRef<'tcx>, | |
912 | ) -> ty::ExistentialTraitRef<'tcx> { | |
94b46f34 XL |
913 | // Assert there is a Self. |
914 | trait_ref.substs.type_at(0); | |
915 | ||
916 | ty::ExistentialTraitRef { | |
917 | def_id: trait_ref.def_id, | |
dfeec247 | 918 | substs: tcx.intern_substs(&trait_ref.substs[1..]), |
94b46f34 XL |
919 | } |
920 | } | |
921 | ||
9fa01778 | 922 | /// Object types don't have a self type specified. Therefore, when |
476ff2be | 923 | /// we convert the principal trait-ref into a normal trait-ref, |
9fa01778 | 924 | /// you must give *some* self type. A common choice is `mk_err()` |
0bf4aa26 | 925 | /// or some placeholder type. |
dc9dc135 | 926 | pub fn with_self_ty(&self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ty::TraitRef<'tcx> { |
a1dfa0c6 XL |
927 | // otherwise the escaping vars would be captured by the binder |
928 | // debug_assert!(!self_ty.has_escaping_bound_vars()); | |
476ff2be | 929 | |
dfeec247 | 930 | ty::TraitRef { def_id: self.def_id, substs: tcx.mk_substs_trait(self_ty, self.substs) } |
476ff2be | 931 | } |
9e0c209e SL |
932 | } |
933 | ||
934 | pub type PolyExistentialTraitRef<'tcx> = Binder<ExistentialTraitRef<'tcx>>; | |
935 | ||
936 | impl<'tcx> PolyExistentialTraitRef<'tcx> { | |
937 | pub fn def_id(&self) -> DefId { | |
83c7162d | 938 | self.skip_binder().def_id |
9e0c209e | 939 | } |
94b46f34 | 940 | |
9fa01778 | 941 | /// Object types don't have a self type specified. Therefore, when |
94b46f34 | 942 | /// we convert the principal trait-ref into a normal trait-ref, |
9fa01778 | 943 | /// you must give *some* self type. A common choice is `mk_err()` |
0bf4aa26 | 944 | /// or some placeholder type. |
dc9dc135 | 945 | pub fn with_self_ty(&self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ty::PolyTraitRef<'tcx> { |
94b46f34 XL |
946 | self.map_bound(|trait_ref| trait_ref.with_self_ty(tcx, self_ty)) |
947 | } | |
9e0c209e SL |
948 | } |
949 | ||
a1dfa0c6 | 950 | /// Binder is a binder for higher-ranked lifetimes or types. It is part of the |
e9174d1e SL |
951 | /// compiler's representation for things like `for<'a> Fn(&'a isize)` |
952 | /// (which would be represented by the type `PolyTraitRef == | |
0bf4aa26 | 953 | /// Binder<TraitRef>`). Note that when we instantiate, |
a1dfa0c6 | 954 | /// erase, or otherwise "discharge" these bound vars, we change the |
e9174d1e | 955 | /// type from `Binder<T>` to just `T` (see |
0731742a | 956 | /// e.g., `liberate_late_bound_regions`). |
5869c6ff XL |
957 | /// |
958 | /// `Decodable` and `Encodable` are implemented for `Binder<T>` using the `impl_binder_encode_decode!` macro. | |
959 | #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)] | |
83c7162d | 960 | pub struct Binder<T>(T); |
e9174d1e SL |
961 | |
962 | impl<T> Binder<T> { | |
ff7c6d11 | 963 | /// Wraps `value` in a binder, asserting that `value` does not |
a1dfa0c6 | 964 | /// contain any bound vars that would be bound by the |
ff7c6d11 XL |
965 | /// binder. This is commonly used to 'inject' a value T into a |
966 | /// different binding level. | |
967 | pub fn dummy<'tcx>(value: T) -> Binder<T> | |
dfeec247 XL |
968 | where |
969 | T: TypeFoldable<'tcx>, | |
ff7c6d11 | 970 | { |
a1dfa0c6 | 971 | debug_assert!(!value.has_escaping_bound_vars()); |
ff7c6d11 XL |
972 | Binder(value) |
973 | } | |
974 | ||
a1dfa0c6 | 975 | /// Wraps `value` in a binder, binding higher-ranked vars (if any). |
dc9dc135 | 976 | pub fn bind(value: T) -> Binder<T> { |
83c7162d XL |
977 | Binder(value) |
978 | } | |
979 | ||
3dfed10e XL |
980 | /// Wraps `value` in a binder without actually binding any currently |
981 | /// unbound variables. | |
982 | /// | |
983 | /// Note that this will shift all debrujin indices of escaping bound variables | |
984 | /// by 1 to avoid accidential captures. | |
985 | pub fn wrap_nonbinding(tcx: TyCtxt<'tcx>, value: T) -> Binder<T> | |
986 | where | |
987 | T: TypeFoldable<'tcx>, | |
988 | { | |
989 | if value.has_escaping_bound_vars() { | |
fc512014 | 990 | Binder::bind(super::fold::shift_vars(tcx, value, 1)) |
3dfed10e XL |
991 | } else { |
992 | Binder::dummy(value) | |
993 | } | |
994 | } | |
995 | ||
e9174d1e SL |
996 | /// Skips the binder and returns the "bound" value. This is a |
997 | /// risky thing to do because it's easy to get confused about | |
9fa01778 | 998 | /// De Bruijn indices and the like. It is usually better to |
a1dfa0c6 | 999 | /// discharge the binder using `no_bound_vars` or |
e9174d1e SL |
1000 | /// `replace_late_bound_regions` or something like |
1001 | /// that. `skip_binder` is only valid when you are either | |
a1dfa0c6 | 1002 | /// extracting data that has nothing to do with bound vars, you |
e9174d1e SL |
1003 | /// are doing some sort of test that does not involve bound |
1004 | /// regions, or you are being very careful about your depth | |
1005 | /// accounting. | |
1006 | /// | |
1007 | /// Some examples where `skip_binder` is reasonable: | |
ff7c6d11 | 1008 | /// |
9fa01778 | 1009 | /// - extracting the `DefId` from a PolyTraitRef; |
e9174d1e | 1010 | /// - comparing the self type of a PolyTraitRef to see if it is equal to |
a1dfa0c6 | 1011 | /// a type parameter `X`, since the type `X` does not reference any regions |
f035d41b XL |
1012 | pub fn skip_binder(self) -> T { |
1013 | self.0 | |
e9174d1e SL |
1014 | } |
1015 | ||
1016 | pub fn as_ref(&self) -> Binder<&T> { | |
83c7162d | 1017 | Binder(&self.0) |
e9174d1e SL |
1018 | } |
1019 | ||
cc61c64b | 1020 | pub fn map_bound_ref<F, U>(&self, f: F) -> Binder<U> |
dfeec247 XL |
1021 | where |
1022 | F: FnOnce(&T) -> U, | |
e9174d1e SL |
1023 | { |
1024 | self.as_ref().map_bound(f) | |
1025 | } | |
1026 | ||
cc61c64b | 1027 | pub fn map_bound<F, U>(self, f: F) -> Binder<U> |
dfeec247 XL |
1028 | where |
1029 | F: FnOnce(T) -> U, | |
e9174d1e | 1030 | { |
83c7162d | 1031 | Binder(f(self.0)) |
e9174d1e | 1032 | } |
ff7c6d11 | 1033 | |
29967ef6 XL |
1034 | /// Wraps a `value` in a binder, using the same bound variables as the |
1035 | /// current `Binder`. This should not be used if the new value *changes* | |
1036 | /// the bound variables. Note: the (old or new) value itself does not | |
1037 | /// necessarily need to *name* all the bound variables. | |
1038 | /// | |
1039 | /// This currently doesn't do anything different than `bind`, because we | |
1040 | /// don't actually track bound vars. However, semantically, it is different | |
1041 | /// because bound vars aren't allowed to change here, whereas they are | |
1042 | /// in `bind`. This may be (debug) asserted in the future. | |
1043 | pub fn rebind<U>(&self, value: U) -> Binder<U> { | |
1044 | Binder(value) | |
1045 | } | |
1046 | ||
ff7c6d11 | 1047 | /// Unwraps and returns the value within, but only if it contains |
a1dfa0c6 | 1048 | /// no bound vars at all. (In other words, if this binder -- |
ff7c6d11 XL |
1049 | /// and indeed any enclosing binder -- doesn't bind anything at |
1050 | /// all.) Otherwise, returns `None`. | |
1051 | /// | |
1052 | /// (One could imagine having a method that just unwraps a single | |
a1dfa0c6 | 1053 | /// binder, but permits late-bound vars bound by enclosing |
ff7c6d11 XL |
1054 | /// binders, but that would require adjusting the debruijn |
1055 | /// indices, and given the shallow binding structure we often use, | |
1056 | /// would not be that useful.) | |
a1dfa0c6 | 1057 | pub fn no_bound_vars<'tcx>(self) -> Option<T> |
dfeec247 XL |
1058 | where |
1059 | T: TypeFoldable<'tcx>, | |
ff7c6d11 | 1060 | { |
f035d41b | 1061 | if self.0.has_escaping_bound_vars() { None } else { Some(self.skip_binder()) } |
ff7c6d11 XL |
1062 | } |
1063 | ||
1064 | /// Given two things that have the same binder level, | |
9fa01778 XL |
1065 | /// and an operation that wraps on their contents, executes the operation |
1066 | /// and then wraps its result. | |
ff7c6d11 XL |
1067 | /// |
1068 | /// `f` should consider bound regions at depth 1 to be free, and | |
1069 | /// anything it produces with bound regions at depth 1 will be | |
1070 | /// bound in the resulting return value. | |
dfeec247 XL |
1071 | pub fn fuse<U, F, R>(self, u: Binder<U>, f: F) -> Binder<R> |
1072 | where | |
1073 | F: FnOnce(T, U) -> R, | |
ff7c6d11 | 1074 | { |
83c7162d | 1075 | Binder(f(self.0, u.0)) |
ff7c6d11 XL |
1076 | } |
1077 | ||
9fa01778 | 1078 | /// Splits the contents into two things that share the same binder |
ff7c6d11 XL |
1079 | /// level as the original, returning two distinct binders. |
1080 | /// | |
1081 | /// `f` should consider bound regions at depth 1 to be free, and | |
1082 | /// anything it produces with bound regions at depth 1 will be | |
1083 | /// bound in the resulting return values. | |
dfeec247 XL |
1084 | pub fn split<U, V, F>(self, f: F) -> (Binder<U>, Binder<V>) |
1085 | where | |
1086 | F: FnOnce(T) -> (U, V), | |
ff7c6d11 XL |
1087 | { |
1088 | let (u, v) = f(self.0); | |
83c7162d | 1089 | (Binder(u), Binder(v)) |
ff7c6d11 | 1090 | } |
e9174d1e SL |
1091 | } |
1092 | ||
3dfed10e XL |
1093 | impl<T> Binder<Option<T>> { |
1094 | pub fn transpose(self) -> Option<Binder<T>> { | |
fc512014 | 1095 | self.0.map(Binder) |
3dfed10e XL |
1096 | } |
1097 | } | |
1098 | ||
e9174d1e SL |
1099 | /// Represents the projection of an associated type. In explicit UFCS |
1100 | /// form this would be written `<T as Trait<..>>::N`. | |
3dfed10e | 1101 | #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
60c5eb7d | 1102 | #[derive(HashStable, TypeFoldable)] |
e9174d1e | 1103 | pub struct ProjectionTy<'tcx> { |
041b39d2 | 1104 | /// The parameters of the associated item. |
532ac7d7 | 1105 | pub substs: SubstsRef<'tcx>, |
e9174d1e | 1106 | |
a1dfa0c6 | 1107 | /// The `DefId` of the `TraitItem` for the associated type `N`. |
7cac9316 | 1108 | /// |
a1dfa0c6 XL |
1109 | /// Note that this is not the `DefId` of the `TraitRef` containing this |
1110 | /// associated type, which is in `tcx.associated_item(item_def_id).container`. | |
7cac9316 | 1111 | pub item_def_id: DefId, |
e9174d1e | 1112 | } |
7cac9316 | 1113 | |
dc9dc135 | 1114 | impl<'tcx> ProjectionTy<'tcx> { |
6a06907d XL |
1115 | pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId { |
1116 | tcx.associated_item(self.item_def_id).container.id() | |
1117 | } | |
7cac9316 | 1118 | |
6a06907d XL |
1119 | /// Extracts the underlying trait reference and own substs from this projection. |
1120 | /// For example, if this is a projection of `<T as StreamingIterator>::Item<'a>`, | |
1121 | /// then this function would return a `T: Iterator` trait reference and `['a]` as the own substs | |
1122 | pub fn trait_ref_and_own_substs( | |
1123 | &self, | |
1124 | tcx: TyCtxt<'tcx>, | |
1125 | ) -> (ty::TraitRef<'tcx>, &'tcx [ty::GenericArg<'tcx>]) { | |
1126 | let def_id = tcx.associated_item(self.item_def_id).container.id(); | |
1127 | let trait_generics = tcx.generics_of(def_id); | |
1128 | ( | |
1129 | ty::TraitRef { def_id, substs: self.substs.truncate_to(tcx, trait_generics) }, | |
1130 | &self.substs[trait_generics.count()..], | |
1131 | ) | |
7cac9316 XL |
1132 | } |
1133 | ||
041b39d2 XL |
1134 | /// Extracts the underlying trait reference from this projection. |
1135 | /// For example, if this is a projection of `<T as Iterator>::Item`, | |
1136 | /// then this function would return a `T: Iterator` trait reference. | |
6a06907d XL |
1137 | /// |
1138 | /// WARNING: This will drop the substs for generic associated types | |
1139 | /// consider calling [Self::trait_ref_and_own_substs] to get those | |
1140 | /// as well. | |
dfeec247 | 1141 | pub fn trait_ref(&self, tcx: TyCtxt<'tcx>) -> ty::TraitRef<'tcx> { |
6a06907d XL |
1142 | let def_id = self.trait_def_id(tcx); |
1143 | ty::TraitRef { def_id, substs: self.substs.truncate_to(tcx, tcx.generics_of(def_id)) } | |
041b39d2 XL |
1144 | } |
1145 | ||
1146 | pub fn self_ty(&self) -> Ty<'tcx> { | |
1147 | self.substs.type_at(0) | |
7cac9316 XL |
1148 | } |
1149 | } | |
1150 | ||
f035d41b | 1151 | #[derive(Copy, Clone, Debug, TypeFoldable)] |
ea8adc8c | 1152 | pub struct GenSig<'tcx> { |
74b04a01 | 1153 | pub resume_ty: Ty<'tcx>, |
ea8adc8c XL |
1154 | pub yield_ty: Ty<'tcx>, |
1155 | pub return_ty: Ty<'tcx>, | |
1156 | } | |
1157 | ||
1158 | pub type PolyGenSig<'tcx> = Binder<GenSig<'tcx>>; | |
1159 | ||
1160 | impl<'tcx> PolyGenSig<'tcx> { | |
74b04a01 XL |
1161 | pub fn resume_ty(&self) -> ty::Binder<Ty<'tcx>> { |
1162 | self.map_bound_ref(|sig| sig.resume_ty) | |
1163 | } | |
ea8adc8c XL |
1164 | pub fn yield_ty(&self) -> ty::Binder<Ty<'tcx>> { |
1165 | self.map_bound_ref(|sig| sig.yield_ty) | |
1166 | } | |
1167 | pub fn return_ty(&self) -> ty::Binder<Ty<'tcx>> { | |
1168 | self.map_bound_ref(|sig| sig.return_ty) | |
1169 | } | |
1170 | } | |
7cac9316 | 1171 | |
e1599b0c | 1172 | /// Signature of a function type, which we have arbitrarily |
e9174d1e SL |
1173 | /// decided to use to refer to the input/output types. |
1174 | /// | |
532ac7d7 XL |
1175 | /// - `inputs`: is the list of arguments and their modes. |
1176 | /// - `output`: is the return type. | |
1177 | /// - `c_variadic`: indicates whether this is a C-variadic function. | |
3dfed10e | 1178 | #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
60c5eb7d | 1179 | #[derive(HashStable, TypeFoldable)] |
e9174d1e | 1180 | pub struct FnSig<'tcx> { |
b7449926 | 1181 | pub inputs_and_output: &'tcx List<Ty<'tcx>>, |
532ac7d7 | 1182 | pub c_variadic: bool, |
8bb4bdeb XL |
1183 | pub unsafety: hir::Unsafety, |
1184 | pub abi: abi::Abi, | |
e9174d1e SL |
1185 | } |
1186 | ||
476ff2be | 1187 | impl<'tcx> FnSig<'tcx> { |
8bb4bdeb | 1188 | pub fn inputs(&self) -> &'tcx [Ty<'tcx>] { |
476ff2be SL |
1189 | &self.inputs_and_output[..self.inputs_and_output.len() - 1] |
1190 | } | |
1191 | ||
1192 | pub fn output(&self) -> Ty<'tcx> { | |
1193 | self.inputs_and_output[self.inputs_and_output.len() - 1] | |
1194 | } | |
48663c56 | 1195 | |
e1599b0c XL |
1196 | // Creates a minimal `FnSig` to be used when encountering a `TyKind::Error` in a fallible |
1197 | // method. | |
48663c56 XL |
1198 | fn fake() -> FnSig<'tcx> { |
1199 | FnSig { | |
1200 | inputs_and_output: List::empty(), | |
1201 | c_variadic: false, | |
1202 | unsafety: hir::Unsafety::Normal, | |
1203 | abi: abi::Abi::Rust, | |
1204 | } | |
1205 | } | |
476ff2be SL |
1206 | } |
1207 | ||
e9174d1e SL |
1208 | pub type PolyFnSig<'tcx> = Binder<FnSig<'tcx>>; |
1209 | ||
1210 | impl<'tcx> PolyFnSig<'tcx> { | |
a1dfa0c6 | 1211 | #[inline] |
8bb4bdeb | 1212 | pub fn inputs(&self) -> Binder<&'tcx [Ty<'tcx>]> { |
83c7162d | 1213 | self.map_bound_ref(|fn_sig| fn_sig.inputs()) |
e9174d1e | 1214 | } |
a1dfa0c6 | 1215 | #[inline] |
e9174d1e | 1216 | pub fn input(&self, index: usize) -> ty::Binder<Ty<'tcx>> { |
476ff2be | 1217 | self.map_bound_ref(|fn_sig| fn_sig.inputs()[index]) |
e9174d1e | 1218 | } |
b7449926 | 1219 | pub fn inputs_and_output(&self) -> ty::Binder<&'tcx List<Ty<'tcx>>> { |
ff7c6d11 XL |
1220 | self.map_bound_ref(|fn_sig| fn_sig.inputs_and_output) |
1221 | } | |
a1dfa0c6 | 1222 | #[inline] |
5bcae85e | 1223 | pub fn output(&self) -> ty::Binder<Ty<'tcx>> { |
0bf4aa26 | 1224 | self.map_bound_ref(|fn_sig| fn_sig.output()) |
e9174d1e | 1225 | } |
532ac7d7 XL |
1226 | pub fn c_variadic(&self) -> bool { |
1227 | self.skip_binder().c_variadic | |
e9174d1e | 1228 | } |
8bb4bdeb XL |
1229 | pub fn unsafety(&self) -> hir::Unsafety { |
1230 | self.skip_binder().unsafety | |
1231 | } | |
1232 | pub fn abi(&self) -> abi::Abi { | |
1233 | self.skip_binder().abi | |
1234 | } | |
e9174d1e SL |
1235 | } |
1236 | ||
0bf4aa26 XL |
1237 | pub type CanonicalPolyFnSig<'tcx> = Canonical<'tcx, Binder<FnSig<'tcx>>>; |
1238 | ||
3dfed10e | 1239 | #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
ba9703b0 | 1240 | #[derive(HashStable)] |
e9174d1e | 1241 | pub struct ParamTy { |
48663c56 | 1242 | pub index: u32, |
e74abb32 | 1243 | pub name: Symbol, |
e9174d1e SL |
1244 | } |
1245 | ||
dc9dc135 | 1246 | impl<'tcx> ParamTy { |
e74abb32 | 1247 | pub fn new(index: u32, name: Symbol) -> ParamTy { |
74b04a01 | 1248 | ParamTy { index, name } |
e9174d1e SL |
1249 | } |
1250 | ||
1251 | pub fn for_self() -> ParamTy { | |
e74abb32 | 1252 | ParamTy::new(0, kw::SelfUpper) |
e9174d1e SL |
1253 | } |
1254 | ||
94b46f34 | 1255 | pub fn for_def(def: &ty::GenericParamDef) -> ParamTy { |
9e0c209e | 1256 | ParamTy::new(def.index, def.name) |
e9174d1e SL |
1257 | } |
1258 | ||
6a06907d | 1259 | #[inline] |
dc9dc135 | 1260 | pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
48663c56 | 1261 | tcx.mk_ty_param(self.index, self.name) |
e9174d1e | 1262 | } |
e9174d1e SL |
1263 | } |
1264 | ||
3dfed10e | 1265 | #[derive(Copy, Clone, Hash, TyEncodable, TyDecodable, Eq, PartialEq, Ord, PartialOrd)] |
ba9703b0 | 1266 | #[derive(HashStable)] |
532ac7d7 XL |
1267 | pub struct ParamConst { |
1268 | pub index: u32, | |
e74abb32 | 1269 | pub name: Symbol, |
532ac7d7 XL |
1270 | } |
1271 | ||
dc9dc135 | 1272 | impl<'tcx> ParamConst { |
e74abb32 | 1273 | pub fn new(index: u32, name: Symbol) -> ParamConst { |
532ac7d7 XL |
1274 | ParamConst { index, name } |
1275 | } | |
1276 | ||
1277 | pub fn for_def(def: &ty::GenericParamDef) -> ParamConst { | |
1278 | ParamConst::new(def.index, def.name) | |
1279 | } | |
1280 | ||
3dfed10e | 1281 | pub fn to_const(self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> &'tcx ty::Const<'tcx> { |
532ac7d7 XL |
1282 | tcx.mk_const_param(self.index, self.name, ty) |
1283 | } | |
1284 | } | |
1285 | ||
7cac9316 XL |
1286 | pub type Region<'tcx> = &'tcx RegionKind; |
1287 | ||
f9f354fc XL |
1288 | /// Representation of regions. Note that the NLL checker uses a distinct |
1289 | /// representation of regions. For this reason, it internally replaces all the | |
1290 | /// regions with inference variables -- the index of the variable is then used | |
1291 | /// to index into internal NLL data structures. See `rustc_mir::borrow_check` | |
1292 | /// module for more information. | |
74b04a01 XL |
1293 | /// |
1294 | /// ## The Region lattice within a given function | |
1295 | /// | |
f9f354fc | 1296 | /// In general, the region lattice looks like |
74b04a01 XL |
1297 | /// |
1298 | /// ``` | |
1299 | /// static ----------+-----...------+ (greatest) | |
1300 | /// | | | | |
1301 | /// early-bound and | | | |
1302 | /// free regions | | | |
1303 | /// | | | | |
74b04a01 XL |
1304 | /// | | | |
1305 | /// empty(root) placeholder(U1) | | |
1306 | /// | / | | |
1307 | /// | / placeholder(Un) | |
1308 | /// empty(U1) -- / | |
1309 | /// | / | |
1310 | /// ... / | |
1311 | /// | / | |
1312 | /// empty(Un) -------- (smallest) | |
1313 | /// ``` | |
e9174d1e | 1314 | /// |
74b04a01 XL |
1315 | /// Early-bound/free regions are the named lifetimes in scope from the |
1316 | /// function declaration. They have relationships to one another | |
1317 | /// determined based on the declared relationships from the | |
f9f354fc | 1318 | /// function. |
74b04a01 XL |
1319 | /// |
1320 | /// Note that inference variables and bound regions are not included | |
1321 | /// in this diagram. In the case of inference variables, they should | |
1322 | /// be inferred to some other region from the diagram. In the case of | |
1323 | /// bound regions, they are excluded because they don't make sense to | |
1324 | /// include -- the diagram indicates the relationship between free | |
1325 | /// regions. | |
1326 | /// | |
1327 | /// ## Inference variables | |
1328 | /// | |
1329 | /// During region inference, we sometimes create inference variables, | |
1330 | /// represented as `ReVar`. These will be inferred by the code in | |
1331 | /// `infer::lexical_region_resolve` to some free region from the | |
1332 | /// lattice above (the minimal region that meets the | |
1333 | /// constraints). | |
1334 | /// | |
1335 | /// During NLL checking, where regions are defined differently, we | |
1336 | /// also use `ReVar` -- in that case, the index is used to index into | |
1337 | /// the NLL region checker's data structures. The variable may in fact | |
1338 | /// represent either a free region or an inference variable, in that | |
1339 | /// case. | |
e9174d1e SL |
1340 | /// |
1341 | /// ## Bound Regions | |
1342 | /// | |
1343 | /// These are regions that are stored behind a binder and must be substituted | |
9fa01778 XL |
1344 | /// with some concrete region before being used. There are two kind of |
1345 | /// bound regions: early-bound, which are bound in an item's `Generics`, | |
532ac7d7 | 1346 | /// and are substituted by a `InternalSubsts`, and late-bound, which are part of |
9fa01778 | 1347 | /// higher-ranked types (e.g., `for<'a> fn(&'a ())`), and are substituted by |
e9174d1e SL |
1348 | /// the likes of `liberate_late_bound_regions`. The distinction exists |
1349 | /// because higher-ranked lifetimes aren't supported in all places. See [1][2]. | |
1350 | /// | |
9fa01778 | 1351 | /// Unlike `Param`s, bound regions are not supposed to exist "in the wild" |
0731742a | 1352 | /// outside their binder, e.g., in types passed to type inference, and |
0bf4aa26 | 1353 | /// should first be substituted (by placeholder regions, free regions, |
e9174d1e SL |
1354 | /// or region variables). |
1355 | /// | |
0bf4aa26 | 1356 | /// ## Placeholder and Free Regions |
e9174d1e SL |
1357 | /// |
1358 | /// One often wants to work with bound regions without knowing their precise | |
1359 | /// identity. For example, when checking a function, the lifetime of a borrow | |
1360 | /// can end up being assigned to some region parameter. In these cases, | |
1361 | /// it must be ensured that bounds on the region can't be accidentally | |
1362 | /// assumed without being checked. | |
1363 | /// | |
0bf4aa26 XL |
1364 | /// To do this, we replace the bound regions with placeholder markers, |
1365 | /// which don't satisfy any relation not explicitly provided. | |
e9174d1e | 1366 | /// |
9fa01778 | 1367 | /// There are two kinds of placeholder regions in rustc: `ReFree` and |
0bf4aa26 | 1368 | /// `RePlaceholder`. When checking an item's body, `ReFree` is supposed |
e9174d1e SL |
1369 | /// to be used. These also support explicit bounds: both the internally-stored |
1370 | /// *scope*, which the region is assumed to outlive, as well as other | |
1371 | /// relations stored in the `FreeRegionMap`. Note that these relations | |
a7813a04 | 1372 | /// aren't checked when you `make_subregion` (or `eq_types`), only by |
e9174d1e SL |
1373 | /// `resolve_regions_and_report_errors`. |
1374 | /// | |
1375 | /// When working with higher-ranked types, some region relations aren't | |
1376 | /// yet known, so you can't just call `resolve_regions_and_report_errors`. | |
0bf4aa26 | 1377 | /// `RePlaceholder` is designed for this purpose. In these contexts, |
e9174d1e | 1378 | /// there's also the risk that some inference variable laying around will |
0bf4aa26 | 1379 | /// get unified with your placeholder region: if you want to check whether |
e9174d1e | 1380 | /// `for<'a> Foo<'_>: 'a`, and you substitute your bound region `'a` |
0bf4aa26 XL |
1381 | /// with a placeholder region `'%a`, the variable `'_` would just be |
1382 | /// instantiated to the placeholder region `'%a`, which is wrong because | |
e9174d1e | 1383 | /// the inference variable is supposed to satisfy the relation |
0bf4aa26 | 1384 | /// *for every value of the placeholder region*. To ensure that doesn't |
e9174d1e | 1385 | /// happen, you can use `leak_check`. This is more clearly explained |
ba9703b0 | 1386 | /// by the [rustc dev guide]. |
e9174d1e | 1387 | /// |
ff7c6d11 XL |
1388 | /// [1]: http://smallcultfollowing.com/babysteps/blog/2013/10/29/intermingled-parameter-lists/ |
1389 | /// [2]: http://smallcultfollowing.com/babysteps/blog/2013/11/04/intermingled-parameter-lists/ | |
ba9703b0 | 1390 | /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html |
3dfed10e | 1391 | #[derive(Clone, PartialEq, Eq, Hash, Copy, TyEncodable, TyDecodable, PartialOrd, Ord)] |
7cac9316 | 1392 | pub enum RegionKind { |
9fa01778 XL |
1393 | /// Region bound in a type or fn declaration which will be |
1394 | /// substituted 'early' -- that is, at the same time when type | |
1395 | /// parameters are substituted. | |
e9174d1e SL |
1396 | ReEarlyBound(EarlyBoundRegion), |
1397 | ||
9fa01778 XL |
1398 | /// Region bound in a function scope, which will be substituted when the |
1399 | /// function is called. | |
fc512014 | 1400 | ReLateBound(ty::DebruijnIndex, BoundRegion), |
e9174d1e SL |
1401 | |
1402 | /// When checking a function body, the types of all arguments and so forth | |
1403 | /// that refer to bound region parameters are modified to refer to free | |
1404 | /// region parameters. | |
1405 | ReFree(FreeRegion), | |
1406 | ||
e9174d1e SL |
1407 | /// Static data that has an "infinite" lifetime. Top in the region lattice. |
1408 | ReStatic, | |
1409 | ||
9fa01778 | 1410 | /// A region variable. Should not exist after typeck. |
e9174d1e SL |
1411 | ReVar(RegionVid), |
1412 | ||
60c5eb7d | 1413 | /// A placeholder region -- basically, the higher-ranked version of `ReFree`. |
e9174d1e | 1414 | /// Should not exist after typeck. |
a1dfa0c6 | 1415 | RePlaceholder(ty::PlaceholderRegion), |
e9174d1e | 1416 | |
74b04a01 XL |
1417 | /// Empty lifetime is for data that is never accessed. We tag the |
1418 | /// empty lifetime with a universe -- the idea is that we don't | |
1419 | /// want `exists<'a> { forall<'b> { 'b: 'a } }` to be satisfiable. | |
1420 | /// Therefore, the `'empty` in a universe `U` is less than all | |
1421 | /// regions visible from `U`, but not less than regions not visible | |
1422 | /// from `U`. | |
1423 | ReEmpty(ty::UniverseIndex), | |
3157f602 | 1424 | |
94b46f34 | 1425 | /// Erased region, used by trait selection, in MIR and during codegen. |
3157f602 | 1426 | ReErased, |
e9174d1e SL |
1427 | } |
1428 | ||
3dfed10e | 1429 | #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, PartialOrd, Ord)] |
e9174d1e | 1430 | pub struct EarlyBoundRegion { |
7cac9316 | 1431 | pub def_id: DefId, |
e9174d1e | 1432 | pub index: u32, |
e74abb32 | 1433 | pub name: Symbol, |
e9174d1e SL |
1434 | } |
1435 | ||
5869c6ff | 1436 | /// A **`const`** **v**ariable **ID**. |
3dfed10e | 1437 | #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
532ac7d7 XL |
1438 | pub struct ConstVid<'tcx> { |
1439 | pub index: u32, | |
1440 | pub phantom: PhantomData<&'tcx ()>, | |
1441 | } | |
1442 | ||
e74abb32 | 1443 | rustc_index::newtype_index! { |
5869c6ff | 1444 | /// A **region** (lifetime) **v**ariable **ID**. |
b7449926 | 1445 | pub struct RegionVid { |
ff7c6d11 | 1446 | DEBUG_FORMAT = custom, |
b7449926 XL |
1447 | } |
1448 | } | |
abe05a73 | 1449 | |
94b46f34 XL |
1450 | impl Atom for RegionVid { |
1451 | fn index(self) -> usize { | |
1452 | Idx::index(self) | |
1453 | } | |
1454 | } | |
1455 | ||
e74abb32 | 1456 | rustc_index::newtype_index! { |
a1dfa0c6 | 1457 | pub struct BoundVar { .. } |
0bf4aa26 XL |
1458 | } |
1459 | ||
3dfed10e | 1460 | #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
ba9703b0 | 1461 | #[derive(HashStable)] |
0bf4aa26 | 1462 | pub struct BoundTy { |
a1dfa0c6 XL |
1463 | pub var: BoundVar, |
1464 | pub kind: BoundTyKind, | |
1465 | } | |
1466 | ||
3dfed10e | 1467 | #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
ba9703b0 | 1468 | #[derive(HashStable)] |
a1dfa0c6 XL |
1469 | pub enum BoundTyKind { |
1470 | Anon, | |
e74abb32 | 1471 | Param(Symbol), |
b7449926 | 1472 | } |
0531ce1d | 1473 | |
a1dfa0c6 XL |
1474 | impl From<BoundVar> for BoundTy { |
1475 | fn from(var: BoundVar) -> Self { | |
dfeec247 | 1476 | BoundTy { var, kind: BoundTyKind::Anon } |
a1dfa0c6 XL |
1477 | } |
1478 | } | |
0bf4aa26 | 1479 | |
9e0c209e | 1480 | /// A `ProjectionPredicate` for an `ExistentialTraitRef`. |
3dfed10e | 1481 | #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
60c5eb7d | 1482 | #[derive(HashStable, TypeFoldable)] |
9e0c209e | 1483 | pub struct ExistentialProjection<'tcx> { |
041b39d2 | 1484 | pub item_def_id: DefId, |
532ac7d7 | 1485 | pub substs: SubstsRef<'tcx>, |
cc61c64b | 1486 | pub ty: Ty<'tcx>, |
e9174d1e SL |
1487 | } |
1488 | ||
9e0c209e SL |
1489 | pub type PolyExistentialProjection<'tcx> = Binder<ExistentialProjection<'tcx>>; |
1490 | ||
dc9dc135 | 1491 | impl<'tcx> ExistentialProjection<'tcx> { |
041b39d2 XL |
1492 | /// Extracts the underlying existential trait reference from this projection. |
1493 | /// For example, if this is a projection of `exists T. <T as Iterator>::Item == X`, | |
1494 | /// then this function would return a `exists T. T: Iterator` existential trait | |
1495 | /// reference. | |
6a06907d | 1496 | pub fn trait_ref(&self, tcx: TyCtxt<'tcx>) -> ty::ExistentialTraitRef<'tcx> { |
041b39d2 | 1497 | let def_id = tcx.associated_item(self.item_def_id).container.id(); |
6a06907d XL |
1498 | let subst_count = tcx.generics_of(def_id).count() - 1; |
1499 | let substs = tcx.intern_substs(&self.substs[..subst_count]); | |
1500 | ty::ExistentialTraitRef { def_id, substs } | |
9e0c209e SL |
1501 | } |
1502 | ||
dc9dc135 XL |
1503 | pub fn with_self_ty( |
1504 | &self, | |
1505 | tcx: TyCtxt<'tcx>, | |
1506 | self_ty: Ty<'tcx>, | |
1507 | ) -> ty::ProjectionPredicate<'tcx> { | |
9e0c209e | 1508 | // otherwise the escaping regions would be captured by the binders |
a1dfa0c6 | 1509 | debug_assert!(!self_ty.has_escaping_bound_vars()); |
9e0c209e | 1510 | |
476ff2be | 1511 | ty::ProjectionPredicate { |
041b39d2 XL |
1512 | projection_ty: ty::ProjectionTy { |
1513 | item_def_id: self.item_def_id, | |
94b46f34 | 1514 | substs: tcx.mk_substs_trait(self_ty, self.substs), |
041b39d2 | 1515 | }, |
cc61c64b | 1516 | ty: self.ty, |
476ff2be | 1517 | } |
e9174d1e | 1518 | } |
6a06907d XL |
1519 | |
1520 | pub fn erase_self_ty( | |
1521 | tcx: TyCtxt<'tcx>, | |
1522 | projection_predicate: ty::ProjectionPredicate<'tcx>, | |
1523 | ) -> Self { | |
1524 | // Assert there is a Self. | |
1525 | projection_predicate.projection_ty.substs.type_at(0); | |
1526 | ||
1527 | Self { | |
1528 | item_def_id: projection_predicate.projection_ty.item_def_id, | |
1529 | substs: tcx.intern_substs(&projection_predicate.projection_ty.substs[1..]), | |
1530 | ty: projection_predicate.ty, | |
1531 | } | |
1532 | } | |
e9174d1e SL |
1533 | } |
1534 | ||
dc9dc135 XL |
1535 | impl<'tcx> PolyExistentialProjection<'tcx> { |
1536 | pub fn with_self_ty( | |
1537 | &self, | |
1538 | tcx: TyCtxt<'tcx>, | |
1539 | self_ty: Ty<'tcx>, | |
1540 | ) -> ty::PolyProjectionPredicate<'tcx> { | |
476ff2be | 1541 | self.map_bound(|p| p.with_self_ty(tcx, self_ty)) |
e9174d1e | 1542 | } |
83c7162d XL |
1543 | |
1544 | pub fn item_def_id(&self) -> DefId { | |
ba9703b0 | 1545 | self.skip_binder().item_def_id |
83c7162d | 1546 | } |
e9174d1e SL |
1547 | } |
1548 | ||
7cac9316 XL |
1549 | /// Region utilities |
1550 | impl RegionKind { | |
0bf4aa26 XL |
1551 | /// Is this region named by the user? |
1552 | pub fn has_name(&self) -> bool { | |
1553 | match *self { | |
1554 | RegionKind::ReEarlyBound(ebr) => ebr.has_name(), | |
fc512014 | 1555 | RegionKind::ReLateBound(_, br) => br.kind.is_named(), |
0bf4aa26 | 1556 | RegionKind::ReFree(fr) => fr.bound_region.is_named(), |
0bf4aa26 XL |
1557 | RegionKind::ReStatic => true, |
1558 | RegionKind::ReVar(..) => false, | |
1559 | RegionKind::RePlaceholder(placeholder) => placeholder.name.is_named(), | |
74b04a01 | 1560 | RegionKind::ReEmpty(_) => false, |
0bf4aa26 | 1561 | RegionKind::ReErased => false, |
0bf4aa26 XL |
1562 | } |
1563 | } | |
1564 | ||
6a06907d | 1565 | #[inline] |
7cac9316 | 1566 | pub fn is_late_bound(&self) -> bool { |
fc512014 | 1567 | matches!(*self, ty::ReLateBound(..)) |
e9174d1e SL |
1568 | } |
1569 | ||
6a06907d | 1570 | #[inline] |
0731742a | 1571 | pub fn is_placeholder(&self) -> bool { |
fc512014 | 1572 | matches!(*self, ty::RePlaceholder(..)) |
0731742a XL |
1573 | } |
1574 | ||
6a06907d | 1575 | #[inline] |
fc512014 | 1576 | pub fn bound_at_or_above_binder(&self, index: ty::DebruijnIndex) -> bool { |
e9174d1e | 1577 | match *self { |
94b46f34 | 1578 | ty::ReLateBound(debruijn, _) => debruijn >= index, |
e9174d1e SL |
1579 | _ => false, |
1580 | } | |
1581 | } | |
1582 | ||
9fa01778 | 1583 | /// Adjusts any De Bruijn indices so as to make `to_binder` the |
94b46f34 XL |
1584 | /// innermost binder. That is, if we have something bound at `to_binder`, |
1585 | /// it will now be bound at INNERMOST. This is an appropriate thing to do | |
1586 | /// when moving a region out from inside binders: | |
1587 | /// | |
1588 | /// ``` | |
1589 | /// for<'a> fn(for<'b> for<'c> fn(&'a u32), _) | |
1590 | /// // Binder: D3 D2 D1 ^^ | |
1591 | /// ``` | |
1592 | /// | |
9fa01778 | 1593 | /// Here, the region `'a` would have the De Bruijn index D3, |
94b46f34 XL |
1594 | /// because it is the bound 3 binders out. However, if we wanted |
1595 | /// to refer to that region `'a` in the second argument (the `_`), | |
1596 | /// those two binders would not be in scope. In that case, we | |
1597 | /// might invoke `shift_out_to_binder(D3)`. This would adjust the | |
9fa01778 | 1598 | /// De Bruijn index of `'a` to D1 (the innermost binder). |
94b46f34 XL |
1599 | /// |
1600 | /// If we invoke `shift_out_to_binder` and the region is in fact | |
1601 | /// bound by one of the binders we are shifting out of, that is an | |
1602 | /// error (and should fail an assertion failure). | |
1603 | pub fn shifted_out_to_binder(&self, to_binder: ty::DebruijnIndex) -> RegionKind { | |
e9174d1e | 1604 | match *self { |
dfeec247 XL |
1605 | ty::ReLateBound(debruijn, r) => { |
1606 | ty::ReLateBound(debruijn.shifted_out_to_binder(to_binder), r) | |
1607 | } | |
1608 | r => r, | |
e9174d1e SL |
1609 | } |
1610 | } | |
c30ab7b3 SL |
1611 | |
1612 | pub fn type_flags(&self) -> TypeFlags { | |
1613 | let mut flags = TypeFlags::empty(); | |
1614 | ||
1615 | match *self { | |
1616 | ty::ReVar(..) => { | |
ff7c6d11 | 1617 | flags = flags | TypeFlags::HAS_FREE_REGIONS; |
74b04a01 | 1618 | flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS; |
c30ab7b3 | 1619 | flags = flags | TypeFlags::HAS_RE_INFER; |
c30ab7b3 | 1620 | } |
0bf4aa26 | 1621 | ty::RePlaceholder(..) => { |
ff7c6d11 | 1622 | flags = flags | TypeFlags::HAS_FREE_REGIONS; |
74b04a01 | 1623 | flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS; |
a1dfa0c6 | 1624 | flags = flags | TypeFlags::HAS_RE_PLACEHOLDER; |
c30ab7b3 | 1625 | } |
ff7c6d11 XL |
1626 | ty::ReEarlyBound(..) => { |
1627 | flags = flags | TypeFlags::HAS_FREE_REGIONS; | |
74b04a01 XL |
1628 | flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS; |
1629 | flags = flags | TypeFlags::HAS_RE_PARAM; | |
ff7c6d11 | 1630 | } |
f9f354fc | 1631 | ty::ReFree { .. } => { |
74b04a01 XL |
1632 | flags = flags | TypeFlags::HAS_FREE_REGIONS; |
1633 | flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS; | |
1634 | } | |
1635 | ty::ReEmpty(_) | ty::ReStatic => { | |
ff7c6d11 XL |
1636 | flags = flags | TypeFlags::HAS_FREE_REGIONS; |
1637 | } | |
74b04a01 XL |
1638 | ty::ReLateBound(..) => { |
1639 | flags = flags | TypeFlags::HAS_RE_LATE_BOUND; | |
1640 | } | |
1641 | ty::ReErased => { | |
1642 | flags = flags | TypeFlags::HAS_RE_ERASED; | |
1643 | } | |
c30ab7b3 SL |
1644 | } |
1645 | ||
1646 | debug!("type_flags({:?}) = {:?}", self, flags); | |
1647 | ||
1648 | flags | |
1649 | } | |
abe05a73 | 1650 | |
9fa01778 | 1651 | /// Given an early-bound or free region, returns the `DefId` where it was bound. |
abe05a73 XL |
1652 | /// For example, consider the regions in this snippet of code: |
1653 | /// | |
1654 | /// ``` | |
1655 | /// impl<'a> Foo { | |
1656 | /// ^^ -- early bound, declared on an impl | |
1657 | /// | |
1658 | /// fn bar<'b, 'c>(x: &self, y: &'b u32, z: &'c u64) where 'static: 'c | |
1659 | /// ^^ ^^ ^ anonymous, late-bound | |
1660 | /// | early-bound, appears in where-clauses | |
1661 | /// late-bound, appears only in fn args | |
1662 | /// {..} | |
1663 | /// } | |
1664 | /// ``` | |
1665 | /// | |
9fa01778 | 1666 | /// Here, `free_region_binding_scope('a)` would return the `DefId` |
abe05a73 | 1667 | /// of the impl, and for all the other highlighted regions, it |
9fa01778 XL |
1668 | /// would return the `DefId` of the function. In other cases (not shown), this |
1669 | /// function might return the `DefId` of a closure. | |
dc9dc135 | 1670 | pub fn free_region_binding_scope(&self, tcx: TyCtxt<'_>) -> DefId { |
abe05a73 | 1671 | match self { |
dfeec247 | 1672 | ty::ReEarlyBound(br) => tcx.parent(br.def_id).unwrap(), |
abe05a73 XL |
1673 | ty::ReFree(fr) => fr.scope, |
1674 | _ => bug!("free_region_binding_scope invoked on inappropriate region: {:?}", self), | |
1675 | } | |
1676 | } | |
e9174d1e SL |
1677 | } |
1678 | ||
7cac9316 | 1679 | /// Type utilities |
dc9dc135 | 1680 | impl<'tcx> TyS<'tcx> { |
1b1a35ee XL |
1681 | #[inline(always)] |
1682 | pub fn kind(&self) -> &TyKind<'tcx> { | |
1683 | &self.kind | |
1684 | } | |
1685 | ||
1686 | #[inline(always)] | |
1687 | pub fn flags(&self) -> TypeFlags { | |
1688 | self.flags | |
1689 | } | |
1690 | ||
dc9dc135 | 1691 | #[inline] |
b7449926 | 1692 | pub fn is_unit(&self) -> bool { |
1b1a35ee | 1693 | match self.kind() { |
b7449926 | 1694 | Tuple(ref tys) => tys.is_empty(), |
cc61c64b | 1695 | _ => false, |
e9174d1e SL |
1696 | } |
1697 | } | |
1698 | ||
dc9dc135 | 1699 | #[inline] |
5bcae85e | 1700 | pub fn is_never(&self) -> bool { |
29967ef6 | 1701 | matches!(self.kind(), Never) |
5bcae85e SL |
1702 | } |
1703 | ||
dc9dc135 | 1704 | #[inline] |
0531ce1d | 1705 | pub fn is_primitive(&self) -> bool { |
1b1a35ee XL |
1706 | self.kind().is_primitive() |
1707 | } | |
1708 | ||
1709 | #[inline] | |
1710 | pub fn is_adt(&self) -> bool { | |
29967ef6 | 1711 | matches!(self.kind(), Adt(..)) |
1b1a35ee XL |
1712 | } |
1713 | ||
1714 | #[inline] | |
1715 | pub fn is_ref(&self) -> bool { | |
29967ef6 | 1716 | matches!(self.kind(), Ref(..)) |
8bb4bdeb XL |
1717 | } |
1718 | ||
a1dfa0c6 | 1719 | #[inline] |
0531ce1d | 1720 | pub fn is_ty_var(&self) -> bool { |
29967ef6 | 1721 | matches!(self.kind(), Infer(TyVar(_))) |
9cc50fc6 SL |
1722 | } |
1723 | ||
dc9dc135 | 1724 | #[inline] |
0531ce1d | 1725 | pub fn is_ty_infer(&self) -> bool { |
29967ef6 | 1726 | matches!(self.kind(), Infer(_)) |
e9174d1e SL |
1727 | } |
1728 | ||
dc9dc135 | 1729 | #[inline] |
b039eaaf | 1730 | pub fn is_phantom_data(&self) -> bool { |
1b1a35ee | 1731 | if let Adt(def, _) = self.kind() { def.is_phantom_data() } else { false } |
b039eaaf SL |
1732 | } |
1733 | ||
dc9dc135 | 1734 | #[inline] |
dfeec247 | 1735 | pub fn is_bool(&self) -> bool { |
1b1a35ee | 1736 | *self.kind() == Bool |
dfeec247 | 1737 | } |
e74abb32 XL |
1738 | |
1739 | /// Returns `true` if this type is a `str`. | |
1740 | #[inline] | |
dfeec247 | 1741 | pub fn is_str(&self) -> bool { |
1b1a35ee | 1742 | *self.kind() == Str |
dfeec247 | 1743 | } |
e9174d1e | 1744 | |
dc9dc135 | 1745 | #[inline] |
9e0c209e | 1746 | pub fn is_param(&self, index: u32) -> bool { |
1b1a35ee | 1747 | match self.kind() { |
48663c56 | 1748 | ty::Param(ref data) => data.index == index, |
e9174d1e SL |
1749 | _ => false, |
1750 | } | |
1751 | } | |
1752 | ||
dc9dc135 | 1753 | #[inline] |
54a0048b | 1754 | pub fn is_slice(&self) -> bool { |
1b1a35ee | 1755 | match self.kind() { |
29967ef6 | 1756 | RawPtr(TypeAndMut { ty, .. }) | Ref(_, ty, _) => matches!(ty.kind(), Slice(_) | Str), |
dfeec247 | 1757 | _ => false, |
e9174d1e SL |
1758 | } |
1759 | } | |
1760 | ||
1b1a35ee XL |
1761 | #[inline] |
1762 | pub fn is_array(&self) -> bool { | |
29967ef6 | 1763 | matches!(self.kind(), Array(..)) |
1b1a35ee XL |
1764 | } |
1765 | ||
e9174d1e SL |
1766 | #[inline] |
1767 | pub fn is_simd(&self) -> bool { | |
1b1a35ee | 1768 | match self.kind() { |
b7449926 | 1769 | Adt(def, _) => def.repr.simd(), |
cc61c64b | 1770 | _ => false, |
e9174d1e SL |
1771 | } |
1772 | } | |
1773 | ||
dc9dc135 | 1774 | pub fn sequence_element_type(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
1b1a35ee | 1775 | match self.kind() { |
b7449926 | 1776 | Array(ty, _) | Slice(ty) => ty, |
5869c6ff | 1777 | Str => tcx.mk_mach_uint(ty::UintTy::U8), |
60c5eb7d | 1778 | _ => bug!("`sequence_element_type` called on non-sequence value: {}", self), |
e9174d1e SL |
1779 | } |
1780 | } | |
1781 | ||
60c5eb7d | 1782 | pub fn simd_size_and_type(&self, tcx: TyCtxt<'tcx>) -> (u64, Ty<'tcx>) { |
1b1a35ee | 1783 | match self.kind() { |
60c5eb7d XL |
1784 | Adt(def, substs) => { |
1785 | let variant = def.non_enum_variant(); | |
fc512014 XL |
1786 | let f0_ty = variant.fields[0].ty(tcx, substs); |
1787 | ||
1788 | match f0_ty.kind() { | |
1789 | Array(f0_elem_ty, f0_len) => { | |
1790 | // FIXME(repr_simd): https://github.com/rust-lang/rust/pull/78863#discussion_r522784112 | |
1791 | // The way we evaluate the `N` in `[T; N]` here only works since we use | |
1792 | // `simd_size_and_type` post-monomorphization. It will probably start to ICE | |
1793 | // if we use it in generic code. See the `simd-array-trait` ui test. | |
1794 | (f0_len.eval_usize(tcx, ParamEnv::empty()) as u64, f0_elem_ty) | |
1795 | } | |
1796 | _ => (variant.fields.len() as u64, f0_ty), | |
1797 | } | |
60c5eb7d XL |
1798 | } |
1799 | _ => bug!("`simd_size_and_type` called on invalid type"), | |
e9174d1e SL |
1800 | } |
1801 | } | |
1802 | ||
dc9dc135 | 1803 | #[inline] |
e9174d1e | 1804 | pub fn is_region_ptr(&self) -> bool { |
29967ef6 | 1805 | matches!(self.kind(), Ref(..)) |
e9174d1e SL |
1806 | } |
1807 | ||
dc9dc135 | 1808 | #[inline] |
416331ca | 1809 | pub fn is_mutable_ptr(&self) -> bool { |
29967ef6 XL |
1810 | matches!( |
1811 | self.kind(), | |
dfeec247 | 1812 | RawPtr(TypeAndMut { mutbl: hir::Mutability::Mut, .. }) |
29967ef6 XL |
1813 | | Ref(_, _, hir::Mutability::Mut) |
1814 | ) | |
32a655c1 SL |
1815 | } |
1816 | ||
6a06907d XL |
1817 | /// Get the mutability of the reference or `None` when not a reference |
1818 | #[inline] | |
1819 | pub fn ref_mutability(&self) -> Option<hir::Mutability> { | |
1820 | match self.kind() { | |
1821 | Ref(_, _, mutability) => Some(*mutability), | |
1822 | _ => None, | |
1823 | } | |
1824 | } | |
1825 | ||
dc9dc135 | 1826 | #[inline] |
e9174d1e | 1827 | pub fn is_unsafe_ptr(&self) -> bool { |
29967ef6 | 1828 | matches!(self.kind(), RawPtr(_)) |
e9174d1e SL |
1829 | } |
1830 | ||
416331ca XL |
1831 | /// Tests if this is any kind of primitive pointer type (reference, raw pointer, fn pointer). |
1832 | #[inline] | |
1833 | pub fn is_any_ptr(&self) -> bool { | |
1834 | self.is_region_ptr() || self.is_unsafe_ptr() || self.is_fn_ptr() | |
1835 | } | |
1836 | ||
dc9dc135 | 1837 | #[inline] |
32a655c1 | 1838 | pub fn is_box(&self) -> bool { |
1b1a35ee | 1839 | match self.kind() { |
b7449926 | 1840 | Adt(def, _) => def.is_box(), |
32a655c1 SL |
1841 | _ => false, |
1842 | } | |
1843 | } | |
1844 | ||
60c5eb7d | 1845 | /// Panics if called on any type other than `Box<T>`. |
32a655c1 | 1846 | pub fn boxed_ty(&self) -> Ty<'tcx> { |
1b1a35ee | 1847 | match self.kind() { |
b7449926 | 1848 | Adt(def, substs) if def.is_box() => substs.type_at(0), |
32a655c1 | 1849 | _ => bug!("`boxed_ty` is called on non-box type {:?}", self), |
e9174d1e SL |
1850 | } |
1851 | } | |
1852 | ||
7cac9316 | 1853 | /// A scalar type is one that denotes an atomic datum, with no sub-components. |
b7449926 | 1854 | /// (A RawPtr is scalar because it represents a non-managed pointer, so its |
7cac9316 | 1855 | /// contents are abstract to rustc.) |
dc9dc135 | 1856 | #[inline] |
e9174d1e | 1857 | pub fn is_scalar(&self) -> bool { |
29967ef6 XL |
1858 | matches!( |
1859 | self.kind(), | |
5869c6ff XL |
1860 | Bool | Char |
1861 | | Int(_) | |
1862 | | Float(_) | |
1863 | | Uint(_) | |
1864 | | FnDef(..) | |
1865 | | FnPtr(_) | |
1866 | | RawPtr(_) | |
1867 | | Infer(IntVar(_) | FloatVar(_)) | |
29967ef6 | 1868 | ) |
e9174d1e SL |
1869 | } |
1870 | ||
9fa01778 | 1871 | /// Returns `true` if this type is a floating point type. |
dc9dc135 | 1872 | #[inline] |
e9174d1e | 1873 | pub fn is_floating_point(&self) -> bool { |
29967ef6 | 1874 | matches!(self.kind(), Float(_) | Infer(FloatVar(_))) |
e9174d1e SL |
1875 | } |
1876 | ||
dc9dc135 | 1877 | #[inline] |
e9174d1e | 1878 | pub fn is_trait(&self) -> bool { |
29967ef6 | 1879 | matches!(self.kind(), Dynamic(..)) |
e9174d1e SL |
1880 | } |
1881 | ||
dc9dc135 | 1882 | #[inline] |
ff7c6d11 | 1883 | pub fn is_enum(&self) -> bool { |
1b1a35ee | 1884 | match self.kind() { |
dfeec247 | 1885 | Adt(adt_def, _) => adt_def.is_enum(), |
ff7c6d11 XL |
1886 | _ => false, |
1887 | } | |
1888 | } | |
1889 | ||
dc9dc135 | 1890 | #[inline] |
7cac9316 | 1891 | pub fn is_closure(&self) -> bool { |
29967ef6 | 1892 | matches!(self.kind(), Closure(..)) |
7cac9316 XL |
1893 | } |
1894 | ||
dc9dc135 | 1895 | #[inline] |
ff7c6d11 | 1896 | pub fn is_generator(&self) -> bool { |
29967ef6 | 1897 | matches!(self.kind(), Generator(..)) |
ff7c6d11 XL |
1898 | } |
1899 | ||
a1dfa0c6 | 1900 | #[inline] |
e9174d1e | 1901 | pub fn is_integral(&self) -> bool { |
29967ef6 | 1902 | matches!(self.kind(), Infer(IntVar(_)) | Int(_) | Uint(_)) |
e9174d1e SL |
1903 | } |
1904 | ||
dc9dc135 | 1905 | #[inline] |
ff7c6d11 | 1906 | pub fn is_fresh_ty(&self) -> bool { |
29967ef6 | 1907 | matches!(self.kind(), Infer(FreshTy(_))) |
ff7c6d11 XL |
1908 | } |
1909 | ||
dc9dc135 | 1910 | #[inline] |
e9174d1e | 1911 | pub fn is_fresh(&self) -> bool { |
29967ef6 | 1912 | matches!(self.kind(), Infer(FreshTy(_) | FreshIntTy(_) | FreshFloatTy(_))) |
e9174d1e SL |
1913 | } |
1914 | ||
dc9dc135 | 1915 | #[inline] |
e9174d1e | 1916 | pub fn is_char(&self) -> bool { |
29967ef6 | 1917 | matches!(self.kind(), Char) |
e9174d1e SL |
1918 | } |
1919 | ||
a1dfa0c6 | 1920 | #[inline] |
e9174d1e | 1921 | pub fn is_numeric(&self) -> bool { |
dc9dc135 | 1922 | self.is_integral() || self.is_floating_point() |
e9174d1e SL |
1923 | } |
1924 | ||
dc9dc135 | 1925 | #[inline] |
e9174d1e | 1926 | pub fn is_signed(&self) -> bool { |
29967ef6 | 1927 | matches!(self.kind(), Int(_)) |
e9174d1e SL |
1928 | } |
1929 | ||
dc9dc135 | 1930 | #[inline] |
416331ca | 1931 | pub fn is_ptr_sized_integral(&self) -> bool { |
5869c6ff | 1932 | matches!(self.kind(), Int(ty::IntTy::Isize) | Uint(ty::UintTy::Usize)) |
0731742a XL |
1933 | } |
1934 | ||
dc9dc135 | 1935 | #[inline] |
e9174d1e | 1936 | pub fn is_machine(&self) -> bool { |
29967ef6 | 1937 | matches!(self.kind(), Int(..) | Uint(..) | Float(..)) |
e9174d1e SL |
1938 | } |
1939 | ||
dc9dc135 | 1940 | #[inline] |
54a0048b | 1941 | pub fn has_concrete_skeleton(&self) -> bool { |
29967ef6 | 1942 | !matches!(self.kind(), Param(_) | Infer(_) | Error(_)) |
54a0048b SL |
1943 | } |
1944 | ||
0731742a | 1945 | /// Returns the type and mutability of `*ty`. |
7cac9316 XL |
1946 | /// |
1947 | /// The parameter `explicit` indicates if this is an *explicit* dereference. | |
0731742a | 1948 | /// Some types -- notably unsafe ptrs -- can only be dereferenced explicitly. |
2c00a5a8 | 1949 | pub fn builtin_deref(&self, explicit: bool) -> Option<TypeAndMut<'tcx>> { |
1b1a35ee | 1950 | match self.kind() { |
b7449926 | 1951 | Adt(def, _) if def.is_box() => { |
dfeec247 XL |
1952 | Some(TypeAndMut { ty: self.boxed_ty(), mutbl: hir::Mutability::Not }) |
1953 | } | |
1b1a35ee XL |
1954 | Ref(_, ty, mutbl) => Some(TypeAndMut { ty, mutbl: *mutbl }), |
1955 | RawPtr(mt) if explicit => Some(*mt), | |
cc61c64b | 1956 | _ => None, |
e9174d1e SL |
1957 | } |
1958 | } | |
1959 | ||
83c7162d | 1960 | /// Returns the type of `ty[i]`. |
e9174d1e | 1961 | pub fn builtin_index(&self) -> Option<Ty<'tcx>> { |
1b1a35ee | 1962 | match self.kind() { |
b7449926 | 1963 | Array(ty, _) | Slice(ty) => Some(ty), |
cc61c64b | 1964 | _ => None, |
e9174d1e SL |
1965 | } |
1966 | } | |
1967 | ||
dc9dc135 | 1968 | pub fn fn_sig(&self, tcx: TyCtxt<'tcx>) -> PolyFnSig<'tcx> { |
1b1a35ee XL |
1969 | match self.kind() { |
1970 | FnDef(def_id, substs) => tcx.fn_sig(*def_id).subst(tcx, substs), | |
1971 | FnPtr(f) => *f, | |
f035d41b | 1972 | Error(_) => { |
dfeec247 | 1973 | // ignore errors (#54954) |
48663c56 XL |
1974 | ty::Binder::dummy(FnSig::fake()) |
1975 | } | |
ba9703b0 XL |
1976 | Closure(..) => bug!( |
1977 | "to get the signature of a closure, use `substs.as_closure().sig()` not `fn_sig()`", | |
1978 | ), | |
dfeec247 | 1979 | _ => bug!("Ty::fn_sig() called on non-fn type: {:?}", self), |
e9174d1e SL |
1980 | } |
1981 | } | |
1982 | ||
dc9dc135 | 1983 | #[inline] |
e9174d1e | 1984 | pub fn is_fn(&self) -> bool { |
29967ef6 | 1985 | matches!(self.kind(), FnDef(..) | FnPtr(_)) |
e9174d1e SL |
1986 | } |
1987 | ||
dc9dc135 XL |
1988 | #[inline] |
1989 | pub fn is_fn_ptr(&self) -> bool { | |
29967ef6 | 1990 | matches!(self.kind(), FnPtr(_)) |
dc9dc135 XL |
1991 | } |
1992 | ||
1993 | #[inline] | |
8faf50e0 | 1994 | pub fn is_impl_trait(&self) -> bool { |
29967ef6 | 1995 | matches!(self.kind(), Opaque(..)) |
e9174d1e SL |
1996 | } |
1997 | ||
a1dfa0c6 | 1998 | #[inline] |
476ff2be | 1999 | pub fn ty_adt_def(&self) -> Option<&'tcx AdtDef> { |
1b1a35ee | 2000 | match self.kind() { |
b7449926 | 2001 | Adt(adt, _) => Some(adt), |
cc61c64b | 2002 | _ => None, |
e9174d1e SL |
2003 | } |
2004 | } | |
2005 | ||
416331ca XL |
2006 | /// Iterates over tuple fields. |
2007 | /// Panics when called on anything but a tuple. | |
dfeec247 | 2008 | pub fn tuple_fields(&self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> { |
1b1a35ee | 2009 | match self.kind() { |
416331ca XL |
2010 | Tuple(substs) => substs.iter().map(|field| field.expect_ty()), |
2011 | _ => bug!("tuple_fields called on non-tuple"), | |
2012 | } | |
2013 | } | |
2014 | ||
fc512014 XL |
2015 | /// Get the `i`-th element of a tuple. |
2016 | /// Panics when called on anything but a tuple. | |
2017 | pub fn tuple_element_ty(&self, i: usize) -> Option<Ty<'tcx>> { | |
2018 | match self.kind() { | |
2019 | Tuple(substs) => substs.iter().nth(i).map(|field| field.expect_ty()), | |
2020 | _ => bug!("tuple_fields called on non-tuple"), | |
2021 | } | |
2022 | } | |
2023 | ||
48663c56 | 2024 | /// If the type contains variants, returns the valid range of variant indices. |
60c5eb7d XL |
2025 | // |
2026 | // FIXME: This requires the optimized MIR in the case of generators. | |
48663c56 | 2027 | #[inline] |
dc9dc135 | 2028 | pub fn variant_range(&self, tcx: TyCtxt<'tcx>) -> Option<Range<VariantIdx>> { |
1b1a35ee | 2029 | match self.kind() { |
48663c56 | 2030 | TyKind::Adt(adt, _) => Some(adt.variant_range()), |
dfeec247 | 2031 | TyKind::Generator(def_id, substs, _) => { |
1b1a35ee | 2032 | Some(substs.as_generator().variant_range(*def_id, tcx)) |
dfeec247 | 2033 | } |
48663c56 XL |
2034 | _ => None, |
2035 | } | |
2036 | } | |
2037 | ||
2038 | /// If the type contains variants, returns the variant for `variant_index`. | |
2039 | /// Panics if `variant_index` is out of range. | |
60c5eb7d XL |
2040 | // |
2041 | // FIXME: This requires the optimized MIR in the case of generators. | |
48663c56 XL |
2042 | #[inline] |
2043 | pub fn discriminant_for_variant( | |
2044 | &self, | |
dc9dc135 XL |
2045 | tcx: TyCtxt<'tcx>, |
2046 | variant_index: VariantIdx, | |
48663c56 | 2047 | ) -> Option<Discr<'tcx>> { |
1b1a35ee | 2048 | match self.kind() { |
f035d41b XL |
2049 | TyKind::Adt(adt, _) if adt.variants.is_empty() => { |
2050 | bug!("discriminant_for_variant called on zero variant enum"); | |
2051 | } | |
f9f354fc XL |
2052 | TyKind::Adt(adt, _) if adt.is_enum() => { |
2053 | Some(adt.discriminant_for_variant(tcx, variant_index)) | |
2054 | } | |
dfeec247 | 2055 | TyKind::Generator(def_id, substs, _) => { |
1b1a35ee | 2056 | Some(substs.as_generator().discriminant_for_variant(*def_id, tcx, variant_index)) |
dfeec247 | 2057 | } |
48663c56 XL |
2058 | _ => None, |
2059 | } | |
2060 | } | |
2061 | ||
f9f354fc | 2062 | /// Returns the type of the discriminant of this type. |
fc512014 | 2063 | pub fn discriminant_ty(&'tcx self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
1b1a35ee | 2064 | match self.kind() { |
f9f354fc XL |
2065 | ty::Adt(adt, _) if adt.is_enum() => adt.repr.discr_type().to_ty(tcx), |
2066 | ty::Generator(_, substs, _) => substs.as_generator().discr_ty(tcx), | |
fc512014 XL |
2067 | |
2068 | ty::Param(_) | ty::Projection(_) | ty::Opaque(..) | ty::Infer(ty::TyVar(_)) => { | |
2069 | let assoc_items = | |
2070 | tcx.associated_items(tcx.lang_items().discriminant_kind_trait().unwrap()); | |
2071 | let discriminant_def_id = assoc_items.in_definition_order().next().unwrap().def_id; | |
2072 | tcx.mk_projection(discriminant_def_id, tcx.mk_substs([self.into()].iter())) | |
2073 | } | |
2074 | ||
2075 | ty::Bool | |
2076 | | ty::Char | |
2077 | | ty::Int(_) | |
2078 | | ty::Uint(_) | |
2079 | | ty::Float(_) | |
2080 | | ty::Adt(..) | |
2081 | | ty::Foreign(_) | |
2082 | | ty::Str | |
2083 | | ty::Array(..) | |
2084 | | ty::Slice(_) | |
2085 | | ty::RawPtr(_) | |
2086 | | ty::Ref(..) | |
2087 | | ty::FnDef(..) | |
2088 | | ty::FnPtr(..) | |
2089 | | ty::Dynamic(..) | |
2090 | | ty::Closure(..) | |
2091 | | ty::GeneratorWitness(..) | |
2092 | | ty::Never | |
2093 | | ty::Tuple(_) | |
2094 | | ty::Error(_) | |
2095 | | ty::Infer(IntVar(_) | FloatVar(_)) => tcx.types.u8, | |
2096 | ||
2097 | ty::Bound(..) | |
2098 | | ty::Placeholder(_) | |
2099 | | ty::Infer(FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => { | |
2100 | bug!("`discriminant_ty` applied to unexpected type: {:?}", self) | |
f9f354fc XL |
2101 | } |
2102 | } | |
2103 | } | |
2104 | ||
6a06907d XL |
2105 | /// Returns the type of metadata for (potentially fat) pointers to this type. |
2106 | pub fn ptr_metadata_ty(&'tcx self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { | |
2107 | // FIXME: should this normalize? | |
2108 | let tail = tcx.struct_tail_without_normalization(self); | |
2109 | match tail.kind() { | |
2110 | // Sized types | |
2111 | ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) | |
2112 | | ty::Uint(_) | |
2113 | | ty::Int(_) | |
2114 | | ty::Bool | |
2115 | | ty::Float(_) | |
2116 | | ty::FnDef(..) | |
2117 | | ty::FnPtr(_) | |
2118 | | ty::RawPtr(..) | |
2119 | | ty::Char | |
2120 | | ty::Ref(..) | |
2121 | | ty::Generator(..) | |
2122 | | ty::GeneratorWitness(..) | |
2123 | | ty::Array(..) | |
2124 | | ty::Closure(..) | |
2125 | | ty::Never | |
2126 | | ty::Error(_) | |
2127 | | ty::Foreign(..) | |
2128 | // If returned by `struct_tail_without_normalization` this is a unit struct | |
2129 | // without any fields, or not a struct, and therefore is Sized. | |
2130 | | ty::Adt(..) | |
2131 | // If returned by `struct_tail_without_normalization` this is the empty tuple, | |
2132 | // a.k.a. unit type, which is Sized | |
2133 | | ty::Tuple(..) => tcx.types.unit, | |
2134 | ||
2135 | ty::Str | ty::Slice(_) => tcx.types.usize, | |
2136 | ty::Dynamic(..) => { | |
2137 | let dyn_metadata = tcx.lang_items().dyn_metadata().unwrap(); | |
2138 | tcx.type_of(dyn_metadata).subst(tcx, &[tail.into()]) | |
2139 | }, | |
2140 | ||
2141 | ty::Projection(_) | |
2142 | | ty::Param(_) | |
2143 | | ty::Opaque(..) | |
2144 | | ty::Infer(ty::TyVar(_)) | |
2145 | | ty::Bound(..) | |
2146 | | ty::Placeholder(..) | |
2147 | | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => { | |
2148 | bug!("`ptr_metadata_ty` applied to unexpected type: {:?}", tail) | |
2149 | } | |
2150 | } | |
2151 | } | |
2152 | ||
ff7c6d11 XL |
2153 | /// When we create a closure, we record its kind (i.e., what trait |
2154 | /// it implements) into its `ClosureSubsts` using a type | |
2155 | /// parameter. This is kind of a phantom type, except that the | |
2156 | /// most convenient thing for us to are the integral types. This | |
2157 | /// function converts such a special type into the closure | |
2158 | /// kind. To go the other way, use | |
2159 | /// `tcx.closure_kind_ty(closure_kind)`. | |
2160 | /// | |
2161 | /// Note that during type checking, we use an inference variable | |
2162 | /// to represent the closure kind, because it has not yet been | |
2163 | /// inferred. Once upvar inference (in `src/librustc_typeck/check/upvar.rs`) | |
2164 | /// is complete, that type variable will be unified. | |
2165 | pub fn to_opt_closure_kind(&self) -> Option<ty::ClosureKind> { | |
1b1a35ee | 2166 | match self.kind() { |
b7449926 | 2167 | Int(int_ty) => match int_ty { |
5869c6ff XL |
2168 | ty::IntTy::I8 => Some(ty::ClosureKind::Fn), |
2169 | ty::IntTy::I16 => Some(ty::ClosureKind::FnMut), | |
2170 | ty::IntTy::I32 => Some(ty::ClosureKind::FnOnce), | |
ff7c6d11 XL |
2171 | _ => bug!("cannot convert type `{:?}` to a closure kind", self), |
2172 | }, | |
2173 | ||
e74abb32 XL |
2174 | // "Bound" types appear in canonical queries when the |
2175 | // closure type is not yet known | |
2176 | Bound(..) | Infer(_) => None, | |
ff7c6d11 | 2177 | |
f035d41b | 2178 | Error(_) => Some(ty::ClosureKind::Fn), |
ff7c6d11 XL |
2179 | |
2180 | _ => bug!("cannot convert type `{:?}` to a closure kind", self), | |
2181 | } | |
2182 | } | |
b7449926 XL |
2183 | |
2184 | /// Fast path helper for testing if a type is `Sized`. | |
2185 | /// | |
2186 | /// Returning true means the type is known to be sized. Returning | |
2187 | /// `false` means nothing -- could be sized, might not be. | |
1b1a35ee XL |
2188 | /// |
2189 | /// Note that we could never rely on the fact that a type such as `[_]` is | |
2190 | /// trivially `!Sized` because we could be in a type environment with a | |
2191 | /// bound such as `[_]: Copy`. A function with such a bound obviously never | |
2192 | /// can be called, but that doesn't mean it shouldn't typecheck. This is why | |
2193 | /// this method doesn't return `Option<bool>`. | |
dc9dc135 | 2194 | pub fn is_trivially_sized(&self, tcx: TyCtxt<'tcx>) -> bool { |
1b1a35ee | 2195 | match self.kind() { |
ba9703b0 | 2196 | ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) |
dfeec247 XL |
2197 | | ty::Uint(_) |
2198 | | ty::Int(_) | |
2199 | | ty::Bool | |
2200 | | ty::Float(_) | |
2201 | | ty::FnDef(..) | |
2202 | | ty::FnPtr(_) | |
2203 | | ty::RawPtr(..) | |
2204 | | ty::Char | |
2205 | | ty::Ref(..) | |
2206 | | ty::Generator(..) | |
2207 | | ty::GeneratorWitness(..) | |
2208 | | ty::Array(..) | |
2209 | | ty::Closure(..) | |
2210 | | ty::Never | |
f035d41b | 2211 | | ty::Error(_) => true, |
dfeec247 XL |
2212 | |
2213 | ty::Str | ty::Slice(_) | ty::Dynamic(..) | ty::Foreign(..) => false, | |
2214 | ||
2215 | ty::Tuple(tys) => tys.iter().all(|ty| ty.expect_ty().is_trivially_sized(tcx)), | |
2216 | ||
2217 | ty::Adt(def, _substs) => def.sized_constraint(tcx).is_empty(), | |
b7449926 XL |
2218 | |
2219 | ty::Projection(_) | ty::Param(_) | ty::Opaque(..) => false, | |
2220 | ||
2221 | ty::Infer(ty::TyVar(_)) => false, | |
2222 | ||
dfeec247 XL |
2223 | ty::Bound(..) |
2224 | | ty::Placeholder(..) | |
ba9703b0 | 2225 | | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => { |
dfeec247 XL |
2226 | bug!("`is_trivially_sized` applied to unexpected type: {:?}", self) |
2227 | } | |
b7449926 XL |
2228 | } |
2229 | } | |
e9174d1e | 2230 | } |