mod bind_instead_of_map;
+mod bytecount;
+mod bytes_count_to_len;
mod bytes_nth;
+mod case_sensitive_file_extension_comparisons;
mod chars_cmp;
mod chars_cmp_with_unwrap;
mod chars_last_cmp;
mod clone_on_copy;
mod clone_on_ref_ptr;
mod cloned_instead_of_copied;
+mod collapsible_str_replace;
+mod err_expect;
mod expect_fun_call;
mod expect_used;
mod extend_with_drain;
mod flat_map_identity;
mod flat_map_option;
mod from_iter_instead_of_collect;
+mod get_first;
+mod get_last_with_len;
mod get_unwrap;
mod implicit_clone;
mod inefficient_to_string;
mod inspect_for_each;
mod into_iter_on_ref;
+mod is_digit_ascii_radix;
mod iter_cloned_collect;
mod iter_count;
+mod iter_kv_map;
mod iter_next_slice;
mod iter_nth;
mod iter_nth_zero;
+mod iter_on_single_or_empty_collections;
+mod iter_overeager_cloned;
mod iter_skip_next;
+mod iter_with_drain;
mod iterator_step_by_zero;
+mod manual_ok_or;
mod manual_saturating_arithmetic;
mod manual_str_repeat;
+mod map_clone;
mod map_collect_result_unit;
+mod map_err_ignore;
mod map_flatten;
mod map_identity;
mod map_unwrap_or;
+mod mut_mutex_lock;
+mod needless_collect;
+mod needless_option_as_deref;
+mod needless_option_take;
+mod no_effect_replace;
+mod obfuscated_if_else;
mod ok_expect;
+mod open_options;
mod option_as_ref_deref;
mod option_map_or_none;
mod option_map_unwrap_or;
mod or_fun_call;
+mod or_then_unwrap;
+mod path_buf_push_overwrite;
+mod range_zip_with_len;
+mod repeat_once;
mod search_is_some;
+mod seek_from_current;
+mod seek_to_start_instead_of_rewind;
mod single_char_add_str;
mod single_char_insert_string;
mod single_char_pattern;
mod single_char_push_string;
mod skip_while_next;
+mod stable_sort_primitive;
+mod str_splitn;
mod string_extend_chars;
mod suspicious_map;
mod suspicious_splitn;
+mod suspicious_to_owned;
mod uninit_assumed_init;
+mod unit_hash;
mod unnecessary_filter_map;
mod unnecessary_fold;
+mod unnecessary_iter_cloned;
+mod unnecessary_join;
mod unnecessary_lazy_eval;
+mod unnecessary_sort_by;
+mod unnecessary_to_owned;
mod unwrap_or_else_default;
mod unwrap_used;
mod useless_asref;
mod utils;
+mod vec_resize_to_zero;
+mod verbose_file_reads;
mod wrong_self_convention;
mod zst_offset;
use bind_instead_of_map::BindInsteadOfMap;
+use clippy_utils::consts::{constant, Constant};
use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
-use clippy_utils::ty::{contains_adt_constructor, contains_ty, implements_trait, is_copy, is_type_diagnostic_item};
-use clippy_utils::{contains_return, get_trait_def_id, in_macro, iter_input_pats, meets_msrv, msrvs, paths, return_ty};
+use clippy_utils::msrvs::{self, Msrv};
+use clippy_utils::ty::{contains_ty_adt_constructor_opaque, implements_trait, is_copy, is_type_diagnostic_item};
+use clippy_utils::{contains_return, is_bool, is_trait_method, iter_input_pats, return_ty};
use if_chain::if_chain;
use rustc_hir as hir;
-use rustc_hir::def::Res;
-use rustc_hir::{Expr, ExprKind, PrimTy, QPath, TraitItem, TraitItemKind};
+use rustc_hir::{Expr, ExprKind, TraitItem, TraitItemKind};
+use rustc_hir_analysis::hir_ty_to_ty;
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::{self, TraitRef, Ty, TyS};
-use rustc_semver::RustcVersion;
+use rustc_middle::ty::{self, TraitRef, Ty};
use rustc_session::{declare_tool_lint, impl_lint_pass};
-use rustc_span::symbol::SymbolStr;
use rustc_span::{sym, Span};
-use rustc_typeck::hir_ty_to_ty;
declare_clippy_lint! {
/// ### What it does
/// ```rust
/// [1, 2, 3].iter().copied();
/// ```
+ #[clippy::version = "1.53.0"]
pub CLONED_INSTEAD_OF_COPIED,
pedantic,
"used `cloned` where `copied` could be used instead"
}
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for consecutive calls to `str::replace` (2 or more)
+ /// that can be collapsed into a single call.
+ ///
+ /// ### Why is this bad?
+ /// Consecutive `str::replace` calls scan the string multiple times
+ /// with repetitive code.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let hello = "hesuo worpd"
+ /// .replace('s', "l")
+ /// .replace("u", "l")
+ /// .replace('p', "l");
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// let hello = "hesuo worpd".replace(['s', 'u', 'p'], "l");
+ /// ```
+ #[clippy::version = "1.65.0"]
+ pub COLLAPSIBLE_STR_REPLACE,
+ perf,
+ "collapse consecutive calls to str::replace (2 or more) into a single call"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for usage of `_.cloned().<func>()` where call to `.cloned()` can be postponed.
+ ///
+ /// ### Why is this bad?
+ /// It's often inefficient to clone all elements of an iterator, when eventually, only some
+ /// of them will be consumed.
+ ///
+ /// ### Known Problems
+ /// This `lint` removes the side of effect of cloning items in the iterator.
+ /// A code that relies on that side-effect could fail.
+ ///
+ /// ### Examples
+ /// ```rust
+ /// # let vec = vec!["string".to_string()];
+ /// vec.iter().cloned().take(10);
+ /// vec.iter().cloned().last();
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// # let vec = vec!["string".to_string()];
+ /// vec.iter().take(10).cloned();
+ /// vec.iter().last().cloned();
+ /// ```
+ #[clippy::version = "1.60.0"]
+ pub ITER_OVEREAGER_CLONED,
+ perf,
+ "using `cloned()` early with `Iterator::iter()` can lead to some performance inefficiencies"
+}
+
declare_clippy_lint! {
/// ### What it does
/// Checks for usages of `Iterator::flat_map()` where `filter_map()` could be
/// ```rust
/// let nums: Vec<i32> = ["1", "2", "whee!"].iter().filter_map(|x| x.parse().ok()).collect();
/// ```
+ #[clippy::version = "1.53.0"]
pub FLAT_MAP_OPTION,
pedantic,
"used `flat_map` where `filter_map` could be used instead"
declare_clippy_lint! {
/// ### What it does
- /// Checks for `.unwrap()` calls on `Option`s and on `Result`s.
+ /// Checks for `.unwrap()` or `.unwrap_err()` calls on `Result`s and `.unwrap()` call on `Option`s.
///
/// ### Why is this bad?
/// It is better to handle the `None` or `Err` case,
///
/// ### Examples
/// ```rust
- /// # let opt = Some(1);
- ///
- /// // Bad
- /// opt.unwrap();
- ///
- /// // Good
- /// opt.expect("more helpful message");
+ /// # let option = Some(1);
+ /// # let result: Result<usize, ()> = Ok(1);
+ /// option.unwrap();
+ /// result.unwrap();
/// ```
///
- /// // or
- ///
+ /// Use instead:
/// ```rust
- /// # let res: Result<usize, ()> = Ok(1);
+ /// # let option = Some(1);
+ /// # let result: Result<usize, ()> = Ok(1);
+ /// option.expect("more helpful message");
+ /// result.expect("more helpful message");
+ /// ```
+ ///
+ /// If [expect_used](#expect_used) is enabled, instead:
+ /// ```rust,ignore
+ /// # let option = Some(1);
+ /// # let result: Result<usize, ()> = Ok(1);
+ /// option?;
///
- /// // Bad
- /// res.unwrap();
+ /// // or
///
- /// // Good
- /// res.expect("more helpful message");
+ /// result?;
/// ```
+ #[clippy::version = "1.45.0"]
pub UNWRAP_USED,
restriction,
"using `.unwrap()` on `Result` or `Option`, which should at least get a better message using `expect()`"
declare_clippy_lint! {
/// ### What it does
- /// Checks for `.expect()` calls on `Option`s and `Result`s.
+ /// Checks for `.expect()` or `.expect_err()` calls on `Result`s and `.expect()` call on `Option`s.
///
/// ### Why is this bad?
/// Usually it is better to handle the `None` or `Err` case.
///
/// ### Examples
/// ```rust,ignore
- /// # let opt = Some(1);
- ///
- /// // Bad
- /// opt.expect("one");
- ///
- /// // Good
- /// let opt = Some(1);
- /// opt?;
+ /// # let option = Some(1);
+ /// # let result: Result<usize, ()> = Ok(1);
+ /// option.expect("one");
+ /// result.expect("one");
/// ```
///
- /// // or
- ///
- /// ```rust
- /// # let res: Result<usize, ()> = Ok(1);
+ /// Use instead:
+ /// ```rust,ignore
+ /// # let option = Some(1);
+ /// # let result: Result<usize, ()> = Ok(1);
+ /// option?;
///
- /// // Bad
- /// res.expect("one");
+ /// // or
///
- /// // Good
- /// res?;
- /// # Ok::<(), ()>(())
+ /// result?;
/// ```
+ #[clippy::version = "1.45.0"]
pub EXPECT_USED,
restriction,
"using `.expect()` on `Result` or `Option`, which might be better handled"
/// }
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub SHOULD_IMPLEMENT_TRAIT,
style,
"defining a method that should be implementing a std trait"
/// Checks for methods with certain name prefixes and which
/// doesn't match how self is taken. The actual rules are:
///
- /// |Prefix |Postfix |`self` taken | `self` type |
- /// |-------|------------|-----------------------|--------------|
- /// |`as_` | none |`&self` or `&mut self` | any |
- /// |`from_`| none | none | any |
- /// |`into_`| none |`self` | any |
- /// |`is_` | none |`&self` or none | any |
- /// |`to_` | `_mut` |`&mut self` | any |
- /// |`to_` | not `_mut` |`self` | `Copy` |
- /// |`to_` | not `_mut` |`&self` | not `Copy` |
+ /// |Prefix |Postfix |`self` taken | `self` type |
+ /// |-------|------------|-------------------------------|--------------|
+ /// |`as_` | none |`&self` or `&mut self` | any |
+ /// |`from_`| none | none | any |
+ /// |`into_`| none |`self` | any |
+ /// |`is_` | none |`&mut self` or `&self` or none | any |
+ /// |`to_` | `_mut` |`&mut self` | any |
+ /// |`to_` | not `_mut` |`self` | `Copy` |
+ /// |`to_` | not `_mut` |`&self` | not `Copy` |
///
/// Note: Clippy doesn't trigger methods with `to_` prefix in:
/// - Traits definition.
/// The method signature is controlled by the trait and often `&self` is required for all types that implement the trait
/// (see e.g. the `std::string::ToString` trait).
///
+ /// Clippy allows `Pin<&Self>` and `Pin<&mut Self>` if `&self` and `&mut self` is required.
+ ///
/// Please find more info here:
/// https://rust-lang.github.io/api-guidelines/naming.html#ad-hoc-conversions-follow-as_-to_-into_-conventions-c-conv
///
/// }
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub WRONG_SELF_CONVENTION,
style,
"defining a method named with an established prefix (like \"into_\") that takes `self` with the wrong convention"
/// ### Example
/// ```rust
/// # let x = Ok::<_, ()>(());
- ///
- /// // Bad
/// x.ok().expect("why did I do this again?");
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
+ /// # let x = Ok::<_, ()>(());
/// x.expect("why did I do this again?");
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub OK_EXPECT,
style,
"using `ok().expect()`, which gives worse error messages than calling `expect` directly on the Result"
}
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for `.err().expect()` calls on the `Result` type.
+ ///
+ /// ### Why is this bad?
+ /// `.expect_err()` can be called directly to avoid the extra type conversion from `err()`.
+ ///
+ /// ### Example
+ /// ```should_panic
+ /// let x: Result<u32, &str> = Ok(10);
+ /// x.err().expect("Testing err().expect()");
+ /// ```
+ /// Use instead:
+ /// ```should_panic
+ /// let x: Result<u32, &str> = Ok(10);
+ /// x.expect_err("Testing expect_err");
+ /// ```
+ #[clippy::version = "1.62.0"]
+ pub ERR_EXPECT,
+ style,
+ r#"using `.err().expect("")` when `.expect_err("")` can be used"#
+}
+
declare_clippy_lint! {
/// ### What it does
/// Checks for usages of `_.unwrap_or_else(Default::default)` on `Option` and
/// ### Examples
/// ```rust
/// # let x = Some(1);
- ///
- /// // Bad
/// x.unwrap_or_else(Default::default);
/// x.unwrap_or_else(u32::default);
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
+ /// # let x = Some(1);
/// x.unwrap_or_default();
/// ```
+ #[clippy::version = "1.56.0"]
pub UNWRAP_OR_ELSE_DEFAULT,
style,
"using `.unwrap_or_else(Default::default)`, which is more succinctly expressed as `.unwrap_or_default()`"
///
/// ### Examples
/// ```rust
- /// # let x = Some(1);
- ///
- /// // Bad
- /// x.map(|a| a + 1).unwrap_or(0);
- ///
- /// // Good
- /// x.map_or(0, |a| a + 1);
+ /// # let option = Some(1);
+ /// # let result: Result<usize, ()> = Ok(1);
+ /// # fn some_function(foo: ()) -> usize { 1 }
+ /// option.map(|a| a + 1).unwrap_or(0);
+ /// result.map(|a| a + 1).unwrap_or_else(some_function);
/// ```
///
- /// // or
- ///
+ /// Use instead:
/// ```rust
- /// # let x: Result<usize, ()> = Ok(1);
+ /// # let option = Some(1);
+ /// # let result: Result<usize, ()> = Ok(1);
/// # fn some_function(foo: ()) -> usize { 1 }
- ///
- /// // Bad
- /// x.map(|a| a + 1).unwrap_or_else(some_function);
- ///
- /// // Good
- /// x.map_or_else(some_function, |a| a + 1);
+ /// option.map_or(0, |a| a + 1);
+ /// result.map_or_else(some_function, |a| a + 1);
/// ```
+ #[clippy::version = "1.45.0"]
pub MAP_UNWRAP_OR,
pedantic,
"using `.map(f).unwrap_or(a)` or `.map(f).unwrap_or_else(func)`, which are more succinctly expressed as `map_or(a, f)` or `map_or_else(a, f)`"
/// ### Example
/// ```rust
/// # let opt = Some(1);
- ///
- /// // Bad
/// opt.map_or(None, |a| Some(a + 1));
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
+ /// # let opt = Some(1);
/// opt.and_then(|a| Some(a + 1));
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub OPTION_MAP_OR_NONE,
style,
"using `Option.map_or(None, f)`, which is more succinctly expressed as `and_then(f)`"
/// `_.ok()`.
///
/// ### Example
- /// Bad:
/// ```rust
/// # let r: Result<u32, &str> = Ok(1);
/// assert_eq!(Some(1), r.map_or(None, Some));
/// ```
///
- /// Good:
+ /// Use instead:
/// ```rust
/// # let r: Result<u32, &str> = Ok(1);
/// assert_eq!(Some(1), r.ok());
/// ```
+ #[clippy::version = "1.44.0"]
pub RESULT_MAP_OR_INTO_OPTION,
style,
"using `Result.map_or(None, Some)`, which is more succinctly expressed as `ok()`"
/// let _ = res().map(|s| if s.len() == 42 { 10 } else { 20 });
/// let _ = res().map_err(|s| if s.len() == 42 { 10 } else { 20 });
/// ```
+ #[clippy::version = "1.45.0"]
pub BIND_INSTEAD_OF_MAP,
complexity,
"using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`"
/// # let vec = vec![1];
/// vec.iter().filter(|x| **x == 0).next();
/// ```
- /// Could be written as
+ ///
+ /// Use instead:
/// ```rust
/// # let vec = vec![1];
/// vec.iter().find(|x| **x == 0);
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub FILTER_NEXT,
complexity,
"using `filter(p).next()`, which is more succinctly expressed as `.find(p)`"
/// # let vec = vec![1];
/// vec.iter().skip_while(|x| **x == 0).next();
/// ```
- /// Could be written as
+ ///
+ /// Use instead:
/// ```rust
/// # let vec = vec![1];
/// vec.iter().find(|x| **x != 0);
/// ```
+ #[clippy::version = "1.42.0"]
pub SKIP_WHILE_NEXT,
complexity,
"using `skip_while(p).next()`, which is more succinctly expressed as `.find(!p)`"
///
/// ### Why is this bad?
/// Readability, this can be written more concisely as
- /// `_.flat_map(_)`
+ /// `_.flat_map(_)` for `Iterator` or `_.and_then(_)` for `Option`
///
/// ### Example
/// ```rust
/// let vec = vec![vec![1]];
+ /// let opt = Some(5);
///
- /// // Bad
/// vec.iter().map(|x| x.iter()).flatten();
+ /// opt.map(|x| Some(x * 2)).flatten();
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
+ /// # let vec = vec![vec![1]];
+ /// # let opt = Some(5);
/// vec.iter().flat_map(|x| x.iter());
+ /// opt.and_then(|x| Some(x * 2));
/// ```
+ #[clippy::version = "1.31.0"]
pub MAP_FLATTEN,
- pedantic,
+ complexity,
"using combinations of `flatten` and `map` which can usually be written as a single method call"
}
/// less performant.
///
/// ### Example
- /// Bad:
/// ```rust
+ /// # #![allow(unused)]
/// (0_i32..10)
/// .filter(|n| n.checked_add(1).is_some())
/// .map(|n| n.checked_add(1).unwrap());
/// ```
///
- /// Good:
+ /// Use instead:
/// ```rust
+ /// # #[allow(unused)]
/// (0_i32..10).filter_map(|n| n.checked_add(1));
/// ```
+ #[clippy::version = "1.51.0"]
pub MANUAL_FILTER_MAP,
complexity,
"using `_.filter(_).map(_)` in a way that can be written more simply as `filter_map(_)`"
/// less performant.
///
/// ### Example
- /// Bad:
/// ```rust
/// (0_i32..10)
/// .find(|n| n.checked_add(1).is_some())
/// .map(|n| n.checked_add(1).unwrap());
/// ```
///
- /// Good:
+ /// Use instead:
/// ```rust
/// (0_i32..10).find_map(|n| n.checked_add(1));
/// ```
+ #[clippy::version = "1.51.0"]
pub MANUAL_FIND_MAP,
complexity,
"using `_.find(_).map(_)` in a way that can be written more simply as `find_map(_)`"
/// ```rust
/// (0..3).find_map(|x| if x == 2 { Some(x) } else { None });
/// ```
+ #[clippy::version = "1.36.0"]
pub FILTER_MAP_NEXT,
pedantic,
"using combination of `filter_map` and `next` which can usually be written as a single method call"
/// # let iter = vec![vec![0]].into_iter();
/// iter.flatten();
/// ```
+ #[clippy::version = "1.39.0"]
pub FLAT_MAP_IDENTITY,
complexity,
"call to `flat_map` where `flatten` is sufficient"
///
/// ### Example
/// ```rust
+ /// # #![allow(unused)]
/// let vec = vec![1];
/// vec.iter().find(|x| **x == 0).is_some();
///
- /// let _ = "hello world".find("world").is_none();
+ /// "hello world".find("world").is_none();
/// ```
- /// Could be written as
+ ///
+ /// Use instead:
/// ```rust
/// let vec = vec![1];
/// vec.iter().any(|x| *x == 0);
///
- /// let _ = !"hello world".contains("world");
+ /// # #[allow(unused)]
+ /// !"hello world".contains("world");
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub SEARCH_IS_SOME,
complexity,
"using an iterator or string search followed by `is_some()` or `is_none()`, which is more succinctly expressed as a call to `any()` or `contains()` (with negation in case of `is_none()`)"
/// let name = "foo";
/// if name.chars().next() == Some('_') {};
/// ```
- /// Could be written as
+ ///
+ /// Use instead:
/// ```rust
/// let name = "foo";
/// if name.starts_with('_') {};
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub CHARS_NEXT_CMP,
style,
"using `.chars().next()` to check if a string starts with a char"
declare_clippy_lint! {
/// ### What it does
/// Checks for calls to `.or(foo(..))`, `.unwrap_or(foo(..))`,
- /// etc., and suggests to use `or_else`, `unwrap_or_else`, etc., or
- /// `unwrap_or_default` instead.
+ /// `.or_insert(foo(..))` etc., and suggests to use `.or_else(|| foo(..))`,
+ /// `.unwrap_or_else(|| foo(..))`, `.unwrap_or_default()` or `.or_default()`
+ /// etc. instead.
///
/// ### Why is this bad?
- /// The function will always be called and potentially
- /// allocate an object acting as the default.
+ /// The function will always be called. This is only bad if it allocates or
+ /// does some non-trivial amount of work.
///
/// ### Known problems
- /// If the function has side-effects, not calling it will
- /// change the semantic of the program, but you shouldn't rely on that anyway.
+ /// If the function has side-effects, not calling it will change the
+ /// semantic of the program, but you shouldn't rely on that.
+ ///
+ /// The lint also cannot figure out whether the function you call is
+ /// actually expensive to call or not.
///
/// ### Example
/// ```rust
/// # let foo = Some(String::new());
- /// foo.unwrap_or(String::new());
+ /// foo.unwrap_or(String::from("empty"));
/// ```
- /// this can instead be written:
- /// ```rust
- /// # let foo = Some(String::new());
- /// foo.unwrap_or_else(String::new);
- /// ```
- /// or
+ ///
+ /// Use instead:
/// ```rust
/// # let foo = Some(String::new());
- /// foo.unwrap_or_default();
+ /// foo.unwrap_or_else(|| String::from("empty"));
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub OR_FUN_CALL,
- perf,
+ nursery,
"using any `*or` method with a function call, which suggests `*or_else`"
}
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for `.or(…).unwrap()` calls to Options and Results.
+ ///
+ /// ### Why is this bad?
+ /// You should use `.unwrap_or(…)` instead for clarity.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # let fallback = "fallback";
+ /// // Result
+ /// # type Error = &'static str;
+ /// # let result: Result<&str, Error> = Err("error");
+ /// let value = result.or::<Error>(Ok(fallback)).unwrap();
+ ///
+ /// // Option
+ /// # let option: Option<&str> = None;
+ /// let value = option.or(Some(fallback)).unwrap();
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// # let fallback = "fallback";
+ /// // Result
+ /// # let result: Result<&str, &str> = Err("error");
+ /// let value = result.unwrap_or(fallback);
+ ///
+ /// // Option
+ /// # let option: Option<&str> = None;
+ /// let value = option.unwrap_or(fallback);
+ /// ```
+ #[clippy::version = "1.61.0"]
+ pub OR_THEN_UNWRAP,
+ complexity,
+ "checks for `.or(…).unwrap()` calls to Options and Results."
+}
+
declare_clippy_lint! {
/// ### What it does
/// Checks for calls to `.expect(&format!(...))`, `.expect(foo(..))`,
/// # let err_code = "418";
/// # let err_msg = "I'm a teapot";
/// foo.expect(&format!("Err {}: {}", err_code, err_msg));
- /// ```
- /// or
- /// ```rust
+ ///
+ /// // or
+ ///
/// # let foo = Some(String::new());
- /// # let err_code = "418";
- /// # let err_msg = "I'm a teapot";
/// foo.expect(format!("Err {}: {}", err_code, err_msg).as_str());
/// ```
- /// this can instead be written:
+ ///
+ /// Use instead:
/// ```rust
/// # let foo = Some(String::new());
/// # let err_code = "418";
/// # let err_msg = "I'm a teapot";
/// foo.unwrap_or_else(|| panic!("Err {}: {}", err_code, err_msg));
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub EXPECT_FUN_CALL,
perf,
"using any `expect` method with a function call"
/// ```rust
/// 42u64.clone();
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub CLONE_ON_COPY,
complexity,
"using `clone` on a `Copy` type"
/// # use std::rc::Rc;
/// let x = Rc::new(1);
///
- /// // Bad
/// x.clone();
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
+ /// # use std::rc::Rc;
+ /// # let x = Rc::new(1);
/// Rc::clone(&x);
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub CLONE_ON_REF_PTR,
restriction,
"using 'clone' on a ref-counted pointer"
/// println!("{:p} {:p}", *y, z); // prints out the same pointer
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub CLONE_DOUBLE_REF,
correctness,
"using `clone` on `&&T`"
/// // OK, the specialized impl is used
/// ["foo", "bar"].iter().map(|&s| s.to_string());
/// ```
+ #[clippy::version = "1.40.0"]
pub INEFFICIENT_TO_STRING,
pedantic,
"using `to_string` on `&&T` where `T: ToString`"
/// fn new() -> Self;
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub NEW_RET_NO_SELF,
style,
"not returning type containing `Self` in a `new` method"
///
/// ### Example
/// ```rust,ignore
- /// // Bad
/// _.split("x");
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust,ignore
/// _.split('x');
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
pub SINGLE_CHAR_PATTERN,
perf,
"using a single-character str where a char could be used, e.g., `_.split(\"x\")`"
/// //..
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub ITERATOR_STEP_BY_ZERO,
correctness,
"using `Iterator::step_by(0)`, which will panic at runtime"
/// ```rust
/// let _ = std::iter::empty::<Option<i32>>().flatten();
/// ```
+ #[clippy::version = "1.53.0"]
pub OPTION_FILTER_MAP,
complexity,
"filtering `Option` for `Some` then force-unwrapping, which can be one type-safe operation"
/// ### Example
/// ```rust
/// # use std::collections::HashSet;
- /// // Bad
/// # let mut s = HashSet::new();
/// # s.insert(1);
/// let x = s.iter().nth(0);
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
+ /// # use std::collections::HashSet;
/// # let mut s = HashSet::new();
/// # s.insert(1);
/// let x = s.iter().next();
/// ```
+ #[clippy::version = "1.42.0"]
pub ITER_NTH_ZERO,
style,
"replace `iter.nth(0)` with `iter.next()`"
declare_clippy_lint! {
/// ### What it does
/// Checks for use of `.iter().nth()` (and the related
- /// `.iter_mut().nth()`) on standard library types with O(1) element access.
+ /// `.iter_mut().nth()`) on standard library types with *O*(1) element access.
///
/// ### Why is this bad?
/// `.get()` and `.get_mut()` are more efficient and more
/// let bad_vec = some_vec.get(3);
/// let bad_slice = &some_vec[..].get(3);
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub ITER_NTH,
perf,
"using `.iter().nth()` on a standard library type with O(1) element access"
/// let bad_vec = some_vec.iter().nth(3);
/// let bad_slice = &some_vec[..].iter().nth(3);
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub ITER_SKIP_NEXT,
style,
"using `.skip(x).next()` on an iterator"
}
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for use of `.drain(..)` on `Vec` and `VecDeque` for iteration.
+ ///
+ /// ### Why is this bad?
+ /// `.into_iter()` is simpler with better performance.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # use std::collections::HashSet;
+ /// let mut foo = vec![0, 1, 2, 3];
+ /// let bar: HashSet<usize> = foo.drain(..).collect();
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// # use std::collections::HashSet;
+ /// let foo = vec![0, 1, 2, 3];
+ /// let bar: HashSet<usize> = foo.into_iter().collect();
+ /// ```
+ #[clippy::version = "1.61.0"]
+ pub ITER_WITH_DRAIN,
+ nursery,
+ "replace `.drain(..)` with `.into_iter()`"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for using `x.get(x.len() - 1)` instead of
+ /// `x.last()`.
+ ///
+ /// ### Why is this bad?
+ /// Using `x.last()` is easier to read and has the same
+ /// result.
+ ///
+ /// Note that using `x[x.len() - 1]` is semantically different from
+ /// `x.last()`. Indexing into the array will panic on out-of-bounds
+ /// accesses, while `x.get()` and `x.last()` will return `None`.
+ ///
+ /// There is another lint (get_unwrap) that covers the case of using
+ /// `x.get(index).unwrap()` instead of `x[index]`.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let x = vec![2, 3, 5];
+ /// let last_element = x.get(x.len() - 1);
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// let x = vec![2, 3, 5];
+ /// let last_element = x.last();
+ /// ```
+ #[clippy::version = "1.37.0"]
+ pub GET_LAST_WITH_LEN,
+ complexity,
+ "Using `x.get(x.len() - 1)` when `x.last()` is correct and simpler"
+}
+
declare_clippy_lint! {
/// ### What it does
/// Checks for use of `.get().unwrap()` (or
/// let last = some_vec[3];
/// some_vec[0] = 1;
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub GET_UNWRAP,
restriction,
"using `.get().unwrap()` or `.get_mut().unwrap()` when using `[]` would work instead"
/// let mut a = vec![1, 2, 3];
/// let mut b = vec![4, 5, 6];
///
- /// // Bad
/// a.extend(b.drain(..));
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// let mut a = vec![1, 2, 3];
+ /// let mut b = vec![4, 5, 6];
///
- /// // Good
/// a.append(&mut b);
/// ```
+ #[clippy::version = "1.55.0"]
pub EXTEND_WITH_DRAIN,
perf,
- "using vec.append(&mut vec) to move the full range of a vecor to another"
+ "using vec.append(&mut vec) to move the full range of a vector to another"
}
declare_clippy_lint! {
/// s.push_str(abc);
/// s.push_str(&def);
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub STRING_EXTEND_CHARS,
style,
"using `x.extend(s.chars())` where s is a `&str` or `String`"
/// let s = [1, 2, 3, 4, 5];
/// let s2: Vec<isize> = s.to_vec();
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub ITER_CLONED_COLLECT,
style,
"using `.cloned().collect()` on slice to create a `Vec`"
/// ### Example
/// ```rust
/// # let name = "_";
- ///
- /// // Bad
/// name.chars().last() == Some('_') || name.chars().next_back() == Some('-');
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
+ /// # let name = "_";
/// name.ends_with('_') || name.ends_with('-');
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub CHARS_LAST_CMP,
style,
"using `.chars().last()` or `.chars().next_back()` to check if a string ends with a char"
/// let x: &[i32] = &[1, 2, 3, 4, 5];
/// do_stuff(x);
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub USELESS_ASREF,
complexity,
"using `as_ref` where the types before and after the call are the same"
///
/// ### Example
/// ```rust
- /// let _ = (0..3).fold(false, |acc, x| acc || x > 2);
+ /// # #[allow(unused)]
+ /// (0..3).fold(false, |acc, x| acc || x > 2);
/// ```
- /// This could be written as:
+ ///
+ /// Use instead:
/// ```rust
- /// let _ = (0..3).any(|x| x > 2);
+ /// (0..3).any(|x| x > 2);
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub UNNECESSARY_FOLD,
style,
"using `fold` when a more succinct alternative exists"
declare_clippy_lint! {
/// ### What it does
- /// Checks for `filter_map` calls which could be replaced by `filter` or `map`.
+ /// Checks for `filter_map` calls that could be replaced by `filter` or `map`.
/// More specifically it checks if the closure provided is only performing one of the
/// filter or map operations and suggests the appropriate option.
///
/// // As there is no conditional check on the argument this could be written as:
/// let _ = (0..4).map(|x| x + 1);
/// ```
+ #[clippy::version = "1.31.0"]
pub UNNECESSARY_FILTER_MAP,
complexity,
"using `filter_map` when a more succinct alternative exists"
}
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for `find_map` calls that could be replaced by `find` or `map`. More
+ /// specifically it checks if the closure provided is only performing one of the
+ /// find or map operations and suggests the appropriate option.
+ ///
+ /// ### Why is this bad?
+ /// Complexity. The intent is also clearer if only a single
+ /// operation is being performed.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let _ = (0..3).find_map(|x| if x > 2 { Some(x) } else { None });
+ ///
+ /// // As there is no transformation of the argument this could be written as:
+ /// let _ = (0..3).find(|&x| x > 2);
+ /// ```
+ ///
+ /// ```rust
+ /// let _ = (0..4).find_map(|x| Some(x + 1));
+ ///
+ /// // As there is no conditional check on the argument this could be written as:
+ /// let _ = (0..4).map(|x| x + 1).next();
+ /// ```
+ #[clippy::version = "1.61.0"]
+ pub UNNECESSARY_FIND_MAP,
+ complexity,
+ "using `find_map` when a more succinct alternative exists"
+}
+
declare_clippy_lint! {
/// ### What it does
/// Checks for `into_iter` calls on references which should be replaced by `iter`
///
/// ### Example
/// ```rust
- /// // Bad
- /// let _ = (&vec![3, 4, 5]).into_iter();
+ /// # let vec = vec![3, 4, 5];
+ /// (&vec).into_iter();
+ /// ```
///
- /// // Good
- /// let _ = (&vec![3, 4, 5]).iter();
+ /// Use instead:
+ /// ```rust
+ /// # let vec = vec![3, 4, 5];
+ /// (&vec).iter();
/// ```
+ #[clippy::version = "1.32.0"]
pub INTO_ITER_ON_REF,
style,
"using `.into_iter()` on a reference"
///
/// ### Why is this bad?
/// It looks suspicious. Maybe `map` was confused with `filter`.
- /// If the `map` call is intentional, this should be rewritten. Or, if you intend to
- /// drive the iterator to completion, you can just use `for_each` instead.
+ /// If the `map` call is intentional, this should be rewritten
+ /// using `inspect`. Or, if you intend to drive the iterator to
+ /// completion, you can just use `for_each` instead.
///
/// ### Example
/// ```rust
/// let _ = (0..3).map(|x| x + 2).count();
/// ```
+ #[clippy::version = "1.39.0"]
pub SUSPICIOUS_MAP,
suspicious,
"suspicious usage of map"
/// MaybeUninit::uninit().assume_init()
/// };
/// ```
+ #[clippy::version = "1.39.0"]
pub UNINIT_ASSUMED_INIT,
correctness,
"`MaybeUninit::uninit().assume_init()`"
/// let add = x.saturating_add(y);
/// let sub = x.saturating_sub(y);
/// ```
+ #[clippy::version = "1.39.0"]
pub MANUAL_SATURATING_ARITHMETIC,
style,
- "`.chcked_add/sub(x).unwrap_or(MAX/MIN)`"
+ "`.checked_add/sub(x).unwrap_or(MAX/MIN)`"
}
declare_clippy_lint! {
/// ```rust
/// unsafe { (&() as *const ()).offset(1) };
/// ```
+ #[clippy::version = "1.41.0"]
pub ZST_OFFSET,
correctness,
"Check for offset calculations on raw pointers to zero-sized types"
/// # Ok::<_, std::io::Error>(())
/// # };
/// ```
+ #[clippy::version = "1.42.0"]
pub FILETYPE_IS_FILE,
restriction,
"`FileType::is_file` is not recommended to test for readable file type"
declare_clippy_lint! {
/// ### What it does
- /// Checks for usage of `_.as_ref().map(Deref::deref)` or it's aliases (such as String::as_str).
+ /// Checks for usage of `_.as_ref().map(Deref::deref)` or its aliases (such as String::as_str).
///
/// ### Why is this bad?
/// Readability, this can be written more concisely as
/// opt.as_deref()
/// # ;
/// ```
+ #[clippy::version = "1.42.0"]
pub OPTION_AS_REF_DEREF,
complexity,
"using `as_ref().map(Deref::deref)`, which is more succinctly expressed as `as_deref()`"
/// a.get(2);
/// b.get(0);
/// ```
+ #[clippy::version = "1.46.0"]
pub ITER_NEXT_SLICE,
style,
"using `.iter().next()` on a sliced array, which can be shortened to just `.get()`"
///
/// ### Example
/// ```rust
- /// let mut string = String::new();
+ /// # let mut string = String::new();
/// string.insert_str(0, "R");
/// string.push_str("R");
/// ```
- /// Could be written as
+ ///
+ /// Use instead:
/// ```rust
- /// let mut string = String::new();
+ /// # let mut string = String::new();
/// string.insert(0, 'R');
/// string.push('R');
/// ```
+ #[clippy::version = "1.49.0"]
pub SINGLE_CHAR_ADD_STR,
style,
"`push_str()` or `insert_str()` used with a single-character string literal as parameter"
///
/// opt.unwrap_or(42);
/// ```
+ #[clippy::version = "1.48.0"]
pub UNNECESSARY_LAZY_EVALUATIONS,
style,
"using unnecessary lazy evaluation, which can be replaced with simpler eager evaluation"
/// ```rust
/// (0..3).try_for_each(|t| Err(t));
/// ```
+ #[clippy::version = "1.49.0"]
pub MAP_COLLECT_RESULT_UNIT,
style,
"using `.map(_).collect::<Result<(),_>()`, which can be replaced with `try_for_each`"
///
/// ### Example
/// ```rust
- /// use std::iter::FromIterator;
- ///
/// let five_fives = std::iter::repeat(5).take(5);
///
/// let v = Vec::from_iter(five_fives);
///
/// assert_eq!(v, vec![5, 5, 5, 5, 5]);
/// ```
+ #[clippy::version = "1.49.0"]
pub FROM_ITER_INSTEAD_OF_COLLECT,
pedantic,
"use `.collect()` instead of `::from_iter()`"
/// assert!(x >= 0);
/// });
/// ```
+ #[clippy::version = "1.51.0"]
pub INSPECT_FOR_EACH,
complexity,
"using `.inspect().for_each()`, which can be replaced with `.for_each()`"
/// # let iter = vec![Some(1)].into_iter();
/// iter.flatten();
/// ```
+ #[clippy::version = "1.52.0"]
pub FILTER_MAP_IDENTITY,
complexity,
"call to `filter_map` where `flatten` is sufficient"
/// let x = [1, 2, 3];
/// let y: Vec<_> = x.iter().map(|x| 2*x).collect();
/// ```
+ #[clippy::version = "1.47.0"]
pub MAP_IDENTITY,
complexity,
"using iterator.map(|x| x)"
///
/// ### Example
/// ```rust
- /// // Bad
- /// let _ = "Hello".bytes().nth(3);
+ /// # #[allow(unused)]
+ /// "Hello".bytes().nth(3);
+ /// ```
///
- /// // Good
- /// let _ = "Hello".as_bytes().get(3);
+ /// Use instead:
+ /// ```rust
+ /// # #[allow(unused)]
+ /// "Hello".as_bytes().get(3);
/// ```
+ #[clippy::version = "1.52.0"]
pub BYTES_NTH,
style,
"replace `.bytes().nth()` with `.as_bytes().get()`"
/// let b = a.clone();
/// let c = a.clone();
/// ```
+ #[clippy::version = "1.52.0"]
pub IMPLICIT_CLONE,
pedantic,
"implicitly cloning a value by invoking a function on its dereferenced type"
///
/// ### Example
/// ```rust
- /// // Bad
+ /// # #![allow(unused)]
/// let some_vec = vec![0, 1, 2, 3];
- /// let _ = some_vec.iter().count();
- /// let _ = &some_vec[..].iter().count();
///
- /// // Good
+ /// some_vec.iter().count();
+ /// &some_vec[..].iter().count();
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
/// let some_vec = vec![0, 1, 2, 3];
- /// let _ = some_vec.len();
- /// let _ = &some_vec[..].len();
+ ///
+ /// some_vec.len();
+ /// &some_vec[..].len();
/// ```
+ #[clippy::version = "1.52.0"]
pub ITER_COUNT,
complexity,
"replace `.iter().count()` with `.len()`"
}
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for the usage of `_.to_owned()`, on a `Cow<'_, _>`.
+ ///
+ /// ### Why is this bad?
+ /// Calling `to_owned()` on a `Cow` creates a clone of the `Cow`
+ /// itself, without taking ownership of the `Cow` contents (i.e.
+ /// it's equivalent to calling `Cow::clone`).
+ /// The similarly named `into_owned` method, on the other hand,
+ /// clones the `Cow` contents, effectively turning any `Cow::Borrowed`
+ /// into a `Cow::Owned`.
+ ///
+ /// Given the potential ambiguity, consider replacing `to_owned`
+ /// with `clone` for better readability or, if getting a `Cow::Owned`
+ /// was the original intent, using `into_owned` instead.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # use std::borrow::Cow;
+ /// let s = "Hello world!";
+ /// let cow = Cow::Borrowed(s);
+ ///
+ /// let data = cow.to_owned();
+ /// assert!(matches!(data, Cow::Borrowed(_)))
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// # use std::borrow::Cow;
+ /// let s = "Hello world!";
+ /// let cow = Cow::Borrowed(s);
+ ///
+ /// let data = cow.clone();
+ /// assert!(matches!(data, Cow::Borrowed(_)))
+ /// ```
+ /// or
+ /// ```rust
+ /// # use std::borrow::Cow;
+ /// let s = "Hello world!";
+ /// let cow = Cow::Borrowed(s);
+ ///
+ /// let _data: String = cow.into_owned();
+ /// ```
+ #[clippy::version = "1.65.0"]
+ pub SUSPICIOUS_TO_OWNED,
+ suspicious,
+ "calls to `to_owned` on a `Cow<'_, _>` might not do what they are expected"
+}
+
declare_clippy_lint! {
/// ### What it does
/// Checks for calls to [`splitn`]
///
/// ### Example
/// ```rust
- /// // Bad
- /// let s = "";
+ /// # let s = "";
/// for x in s.splitn(1, ":") {
- /// // use x
+ /// // ..
/// }
+ /// ```
///
- /// // Good
- /// let s = "";
+ /// Use instead:
+ /// ```rust
+ /// # let s = "";
/// for x in s.splitn(2, ":") {
- /// // use x
+ /// // ..
/// }
/// ```
+ #[clippy::version = "1.54.0"]
pub SUSPICIOUS_SPLITN,
correctness,
"checks for `.splitn(0, ..)` and `.splitn(1, ..)`"
///
/// ### Example
/// ```rust
- /// // Bad
/// let x: String = std::iter::repeat('x').take(10).collect();
+ /// ```
///
- /// // Good
+ /// Use instead:
+ /// ```rust
/// let x: String = "x".repeat(10);
/// ```
+ #[clippy::version = "1.54.0"]
pub MANUAL_STR_REPEAT,
perf,
"manual implementation of `str::repeat`"
}
-pub struct Methods {
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for usages of `str::splitn(2, _)`
+ ///
+ /// ### Why is this bad?
+ /// `split_once` is both clearer in intent and slightly more efficient.
+ ///
+ /// ### Example
+ /// ```rust,ignore
+ /// let s = "key=value=add";
+ /// let (key, value) = s.splitn(2, '=').next_tuple()?;
+ /// let value = s.splitn(2, '=').nth(1)?;
+ ///
+ /// let mut parts = s.splitn(2, '=');
+ /// let key = parts.next()?;
+ /// let value = parts.next()?;
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust,ignore
+ /// let s = "key=value=add";
+ /// let (key, value) = s.split_once('=')?;
+ /// let value = s.split_once('=')?.1;
+ ///
+ /// let (key, value) = s.split_once('=')?;
+ /// ```
+ ///
+ /// ### Limitations
+ /// The multiple statement variant currently only detects `iter.next()?`/`iter.next().unwrap()`
+ /// in two separate `let` statements that immediately follow the `splitn()`
+ #[clippy::version = "1.57.0"]
+ pub MANUAL_SPLIT_ONCE,
+ complexity,
+ "replace `.splitn(2, pat)` with `.split_once(pat)`"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for usages of `str::splitn` (or `str::rsplitn`) where using `str::split` would be the same.
+ /// ### Why is this bad?
+ /// The function `split` is simpler and there is no performance difference in these cases, considering
+ /// that both functions return a lazy iterator.
+ /// ### Example
+ /// ```rust
+ /// let str = "key=value=add";
+ /// let _ = str.splitn(3, '=').next().unwrap();
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// let str = "key=value=add";
+ /// let _ = str.split('=').next().unwrap();
+ /// ```
+ #[clippy::version = "1.59.0"]
+ pub NEEDLESS_SPLITN,
+ complexity,
+ "usages of `str::splitn` that can be replaced with `str::split`"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for unnecessary calls to [`ToOwned::to_owned`](https://doc.rust-lang.org/std/borrow/trait.ToOwned.html#tymethod.to_owned)
+ /// and other `to_owned`-like functions.
+ ///
+ /// ### Why is this bad?
+ /// The unnecessary calls result in useless allocations.
+ ///
+ /// ### Known problems
+ /// `unnecessary_to_owned` can falsely trigger if `IntoIterator::into_iter` is applied to an
+ /// owned copy of a resource and the resource is later used mutably. See
+ /// [#8148](https://github.com/rust-lang/rust-clippy/issues/8148).
+ ///
+ /// ### Example
+ /// ```rust
+ /// let path = std::path::Path::new("x");
+ /// foo(&path.to_string_lossy().to_string());
+ /// fn foo(s: &str) {}
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// let path = std::path::Path::new("x");
+ /// foo(&path.to_string_lossy());
+ /// fn foo(s: &str) {}
+ /// ```
+ #[clippy::version = "1.59.0"]
+ pub UNNECESSARY_TO_OWNED,
+ perf,
+ "unnecessary calls to `to_owned`-like functions"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for use of `.collect::<Vec<String>>().join("")` on iterators.
+ ///
+ /// ### Why is this bad?
+ /// `.collect::<String>()` is more concise and might be more performant
+ ///
+ /// ### Example
+ /// ```rust
+ /// let vector = vec!["hello", "world"];
+ /// let output = vector.iter().map(|item| item.to_uppercase()).collect::<Vec<String>>().join("");
+ /// println!("{}", output);
+ /// ```
+ /// The correct use would be:
+ /// ```rust
+ /// let vector = vec!["hello", "world"];
+ /// let output = vector.iter().map(|item| item.to_uppercase()).collect::<String>();
+ /// println!("{}", output);
+ /// ```
+ /// ### Known problems
+ /// While `.collect::<String>()` is sometimes more performant, there are cases where
+ /// using `.collect::<String>()` over `.collect::<Vec<String>>().join("")`
+ /// will prevent loop unrolling and will result in a negative performance impact.
+ ///
+ /// Additionally, differences have been observed between aarch64 and x86_64 assembly output,
+ /// with aarch64 tending to producing faster assembly in more cases when using `.collect::<String>()`
+ #[clippy::version = "1.61.0"]
+ pub UNNECESSARY_JOIN,
+ pedantic,
+ "using `.collect::<Vec<String>>().join(\"\")` on an iterator"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for no-op uses of `Option::{as_deref, as_deref_mut}`,
+ /// for example, `Option<&T>::as_deref()` returns the same type.
+ ///
+ /// ### Why is this bad?
+ /// Redundant code and improving readability.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let a = Some(&1);
+ /// let b = a.as_deref(); // goes from Option<&i32> to Option<&i32>
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// let a = Some(&1);
+ /// let b = a;
+ /// ```
+ #[clippy::version = "1.57.0"]
+ pub NEEDLESS_OPTION_AS_DEREF,
+ complexity,
+ "no-op use of `deref` or `deref_mut` method to `Option`."
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Finds usages of [`char::is_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_digit) that
+ /// can be replaced with [`is_ascii_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_ascii_digit) or
+ /// [`is_ascii_hexdigit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_ascii_hexdigit).
+ ///
+ /// ### Why is this bad?
+ /// `is_digit(..)` is slower and requires specifying the radix.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let c: char = '6';
+ /// c.is_digit(10);
+ /// c.is_digit(16);
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// let c: char = '6';
+ /// c.is_ascii_digit();
+ /// c.is_ascii_hexdigit();
+ /// ```
+ #[clippy::version = "1.62.0"]
+ pub IS_DIGIT_ASCII_RADIX,
+ style,
+ "use of `char::is_digit(..)` with literal radix of 10 or 16"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for calling `take` function after `as_ref`.
+ ///
+ /// ### Why is this bad?
+ /// Redundant code. `take` writes `None` to its argument.
+ /// In this case the modification is useless as it's a temporary that cannot be read from afterwards.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let x = Some(3);
+ /// x.as_ref().take();
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// let x = Some(3);
+ /// x.as_ref();
+ /// ```
+ #[clippy::version = "1.62.0"]
+ pub NEEDLESS_OPTION_TAKE,
+ complexity,
+ "using `.as_ref().take()` on a temporary value"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for `replace` statements which have no effect.
+ ///
+ /// ### Why is this bad?
+ /// It's either a mistake or confusing.
+ ///
+ /// ### Example
+ /// ```rust
+ /// "1234".replace("12", "12");
+ /// "1234".replacen("12", "12", 1);
+ /// ```
+ #[clippy::version = "1.63.0"]
+ pub NO_EFFECT_REPLACE,
+ suspicious,
+ "replace with no effect"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for usages of `.then_some(..).unwrap_or(..)`
+ ///
+ /// ### Why is this bad?
+ /// This can be written more clearly with `if .. else ..`
+ ///
+ /// ### Limitations
+ /// This lint currently only looks for usages of
+ /// `.then_some(..).unwrap_or(..)`, but will be expanded
+ /// to account for similar patterns.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let x = true;
+ /// x.then_some("a").unwrap_or("b");
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// let x = true;
+ /// if x { "a" } else { "b" };
+ /// ```
+ #[clippy::version = "1.64.0"]
+ pub OBFUSCATED_IF_ELSE,
+ style,
+ "use of `.then_some(..).unwrap_or(..)` can be written \
+ more clearly with `if .. else ..`"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ ///
+ /// Checks for calls to `iter`, `iter_mut` or `into_iter` on collections containing a single item
+ ///
+ /// ### Why is this bad?
+ ///
+ /// It is simpler to use the once function from the standard library:
+ ///
+ /// ### Example
+ ///
+ /// ```rust
+ /// let a = [123].iter();
+ /// let b = Some(123).into_iter();
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// use std::iter;
+ /// let a = iter::once(&123);
+ /// let b = iter::once(123);
+ /// ```
+ ///
+ /// ### Known problems
+ ///
+ /// The type of the resulting iterator might become incompatible with its usage
+ #[clippy::version = "1.65.0"]
+ pub ITER_ON_SINGLE_ITEMS,
+ nursery,
+ "Iterator for array of length 1"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ ///
+ /// Checks for calls to `iter`, `iter_mut` or `into_iter` on empty collections
+ ///
+ /// ### Why is this bad?
+ ///
+ /// It is simpler to use the empty function from the standard library:
+ ///
+ /// ### Example
+ ///
+ /// ```rust
+ /// use std::{slice, option};
+ /// let a: slice::Iter<i32> = [].iter();
+ /// let f: option::IntoIter<i32> = None.into_iter();
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// use std::iter;
+ /// let a: iter::Empty<i32> = iter::empty();
+ /// let b: iter::Empty<i32> = iter::empty();
+ /// ```
+ ///
+ /// ### Known problems
+ ///
+ /// The type of the resulting iterator might become incompatible with its usage
+ #[clippy::version = "1.65.0"]
+ pub ITER_ON_EMPTY_COLLECTIONS,
+ nursery,
+ "Iterator for empty array"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for naive byte counts
+ ///
+ /// ### Why is this bad?
+ /// The [`bytecount`](https://crates.io/crates/bytecount)
+ /// crate has methods to count your bytes faster, especially for large slices.
+ ///
+ /// ### Known problems
+ /// If you have predominantly small slices, the
+ /// `bytecount::count(..)` method may actually be slower. However, if you can
+ /// ensure that less than 2³²-1 matches arise, the `naive_count_32(..)` can be
+ /// faster in those cases.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # let vec = vec![1_u8];
+ /// let count = vec.iter().filter(|x| **x == 0u8).count();
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust,ignore
+ /// # let vec = vec![1_u8];
+ /// let count = bytecount::count(&vec, 0u8);
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
+ pub NAIVE_BYTECOUNT,
+ pedantic,
+ "use of naive `<slice>.filter(|&x| x == y).count()` to count byte values"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// It checks for `str::bytes().count()` and suggests replacing it with
+ /// `str::len()`.
+ ///
+ /// ### Why is this bad?
+ /// `str::bytes().count()` is longer and may not be as performant as using
+ /// `str::len()`.
+ ///
+ /// ### Example
+ /// ```rust
+ /// "hello".bytes().count();
+ /// String::from("hello").bytes().count();
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// "hello".len();
+ /// String::from("hello").len();
+ /// ```
+ #[clippy::version = "1.62.0"]
+ pub BYTES_COUNT_TO_LEN,
+ complexity,
+ "Using `bytes().count()` when `len()` performs the same functionality"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for calls to `ends_with` with possible file extensions
+ /// and suggests to use a case-insensitive approach instead.
+ ///
+ /// ### Why is this bad?
+ /// `ends_with` is case-sensitive and may not detect files with a valid extension.
+ ///
+ /// ### Example
+ /// ```rust
+ /// fn is_rust_file(filename: &str) -> bool {
+ /// filename.ends_with(".rs")
+ /// }
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// fn is_rust_file(filename: &str) -> bool {
+ /// let filename = std::path::Path::new(filename);
+ /// filename.extension()
+ /// .map_or(false, |ext| ext.eq_ignore_ascii_case("rs"))
+ /// }
+ /// ```
+ #[clippy::version = "1.51.0"]
+ pub CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
+ pedantic,
+ "Checks for calls to ends_with with case-sensitive file extensions"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for using `x.get(0)` instead of
+ /// `x.first()`.
+ ///
+ /// ### Why is this bad?
+ /// Using `x.first()` is easier to read and has the same
+ /// result.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let x = vec![2, 3, 5];
+ /// let first_element = x.get(0);
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// let x = vec![2, 3, 5];
+ /// let first_element = x.first();
+ /// ```
+ #[clippy::version = "1.63.0"]
+ pub GET_FIRST,
+ style,
+ "Using `x.get(0)` when `x.first()` is simpler"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ ///
+ /// Finds patterns that reimplement `Option::ok_or`.
+ ///
+ /// ### Why is this bad?
+ ///
+ /// Concise code helps focusing on behavior instead of boilerplate.
+ ///
+ /// ### Examples
+ /// ```rust
+ /// let foo: Option<i32> = None;
+ /// foo.map_or(Err("error"), |v| Ok(v));
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// let foo: Option<i32> = None;
+ /// foo.ok_or("error");
+ /// ```
+ #[clippy::version = "1.49.0"]
+ pub MANUAL_OK_OR,
+ pedantic,
+ "finds patterns that can be encoded more concisely with `Option::ok_or`"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for usage of `map(|x| x.clone())` or
+ /// dereferencing closures for `Copy` types, on `Iterator` or `Option`,
+ /// and suggests `cloned()` or `copied()` instead
+ ///
+ /// ### Why is this bad?
+ /// Readability, this can be written more concisely
+ ///
+ /// ### Example
+ /// ```rust
+ /// let x = vec![42, 43];
+ /// let y = x.iter();
+ /// let z = y.map(|i| *i);
+ /// ```
+ ///
+ /// The correct use would be:
+ ///
+ /// ```rust
+ /// let x = vec![42, 43];
+ /// let y = x.iter();
+ /// let z = y.cloned();
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
+ pub MAP_CLONE,
+ style,
+ "using `iterator.map(|x| x.clone())`, or dereferencing closures for `Copy` types"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for instances of `map_err(|_| Some::Enum)`
+ ///
+ /// ### Why is this bad?
+ /// This `map_err` throws away the original error rather than allowing the enum to contain and report the cause of the error
+ ///
+ /// ### Example
+ /// Before:
+ /// ```rust
+ /// use std::fmt;
+ ///
+ /// #[derive(Debug)]
+ /// enum Error {
+ /// Indivisible,
+ /// Remainder(u8),
+ /// }
+ ///
+ /// impl fmt::Display for Error {
+ /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ /// match self {
+ /// Error::Indivisible => write!(f, "could not divide input by three"),
+ /// Error::Remainder(remainder) => write!(
+ /// f,
+ /// "input is not divisible by three, remainder = {}",
+ /// remainder
+ /// ),
+ /// }
+ /// }
+ /// }
+ ///
+ /// impl std::error::Error for Error {}
+ ///
+ /// fn divisible_by_3(input: &str) -> Result<(), Error> {
+ /// input
+ /// .parse::<i32>()
+ /// .map_err(|_| Error::Indivisible)
+ /// .map(|v| v % 3)
+ /// .and_then(|remainder| {
+ /// if remainder == 0 {
+ /// Ok(())
+ /// } else {
+ /// Err(Error::Remainder(remainder as u8))
+ /// }
+ /// })
+ /// }
+ /// ```
+ ///
+ /// After:
+ /// ```rust
+ /// use std::{fmt, num::ParseIntError};
+ ///
+ /// #[derive(Debug)]
+ /// enum Error {
+ /// Indivisible(ParseIntError),
+ /// Remainder(u8),
+ /// }
+ ///
+ /// impl fmt::Display for Error {
+ /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ /// match self {
+ /// Error::Indivisible(_) => write!(f, "could not divide input by three"),
+ /// Error::Remainder(remainder) => write!(
+ /// f,
+ /// "input is not divisible by three, remainder = {}",
+ /// remainder
+ /// ),
+ /// }
+ /// }
+ /// }
+ ///
+ /// impl std::error::Error for Error {
+ /// fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+ /// match self {
+ /// Error::Indivisible(source) => Some(source),
+ /// _ => None,
+ /// }
+ /// }
+ /// }
+ ///
+ /// fn divisible_by_3(input: &str) -> Result<(), Error> {
+ /// input
+ /// .parse::<i32>()
+ /// .map_err(Error::Indivisible)
+ /// .map(|v| v % 3)
+ /// .and_then(|remainder| {
+ /// if remainder == 0 {
+ /// Ok(())
+ /// } else {
+ /// Err(Error::Remainder(remainder as u8))
+ /// }
+ /// })
+ /// }
+ /// ```
+ #[clippy::version = "1.48.0"]
+ pub MAP_ERR_IGNORE,
+ restriction,
+ "`map_err` should not ignore the original error"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for `&mut Mutex::lock` calls
+ ///
+ /// ### Why is this bad?
+ /// `Mutex::lock` is less efficient than
+ /// calling `Mutex::get_mut`. In addition you also have a statically
+ /// guarantee that the mutex isn't locked, instead of just a runtime
+ /// guarantee.
+ ///
+ /// ### Example
+ /// ```rust
+ /// use std::sync::{Arc, Mutex};
+ ///
+ /// let mut value_rc = Arc::new(Mutex::new(42_u8));
+ /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap();
+ ///
+ /// let mut value = value_mutex.lock().unwrap();
+ /// *value += 1;
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// use std::sync::{Arc, Mutex};
+ ///
+ /// let mut value_rc = Arc::new(Mutex::new(42_u8));
+ /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap();
+ ///
+ /// let value = value_mutex.get_mut().unwrap();
+ /// *value += 1;
+ /// ```
+ #[clippy::version = "1.49.0"]
+ pub MUT_MUTEX_LOCK,
+ style,
+ "`&mut Mutex::lock` does unnecessary locking"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for duplicate open options as well as combinations
+ /// that make no sense.
+ ///
+ /// ### Why is this bad?
+ /// In the best case, the code will be harder to read than
+ /// necessary. I don't know the worst case.
+ ///
+ /// ### Example
+ /// ```rust
+ /// use std::fs::OpenOptions;
+ ///
+ /// OpenOptions::new().read(true).truncate(true);
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
+ pub NONSENSICAL_OPEN_OPTIONS,
+ correctness,
+ "nonsensical combination of options for opening a file"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ ///* Checks for [push](https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.push)
+ /// calls on `PathBuf` that can cause overwrites.
+ ///
+ /// ### Why is this bad?
+ /// Calling `push` with a root path at the start can overwrite the
+ /// previous defined path.
+ ///
+ /// ### Example
+ /// ```rust
+ /// use std::path::PathBuf;
+ ///
+ /// let mut x = PathBuf::from("/foo");
+ /// x.push("/bar");
+ /// assert_eq!(x, PathBuf::from("/bar"));
+ /// ```
+ /// Could be written:
+ ///
+ /// ```rust
+ /// use std::path::PathBuf;
+ ///
+ /// let mut x = PathBuf::from("/foo");
+ /// x.push("bar");
+ /// assert_eq!(x, PathBuf::from("/foo/bar"));
+ /// ```
+ #[clippy::version = "1.36.0"]
+ pub PATH_BUF_PUSH_OVERWRITE,
+ nursery,
+ "calling `push` with file system root on `PathBuf` can overwrite it"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for zipping a collection with the range of
+ /// `0.._.len()`.
+ ///
+ /// ### Why is this bad?
+ /// The code is better expressed with `.enumerate()`.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # let x = vec![1];
+ /// let _ = x.iter().zip(0..x.len());
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// # let x = vec![1];
+ /// let _ = x.iter().enumerate();
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
+ pub RANGE_ZIP_WITH_LEN,
+ complexity,
+ "zipping iterator with a range when `enumerate()` would do"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for usage of `.repeat(1)` and suggest the following method for each types.
+ /// - `.to_string()` for `str`
+ /// - `.clone()` for `String`
+ /// - `.to_vec()` for `slice`
+ ///
+ /// The lint will evaluate constant expressions and values as arguments of `.repeat(..)` and emit a message if
+ /// they are equivalent to `1`. (Related discussion in [rust-clippy#7306](https://github.com/rust-lang/rust-clippy/issues/7306))
+ ///
+ /// ### Why is this bad?
+ /// For example, `String.repeat(1)` is equivalent to `.clone()`. If cloning
+ /// the string is the intention behind this, `clone()` should be used.
+ ///
+ /// ### Example
+ /// ```rust
+ /// fn main() {
+ /// let x = String::from("hello world").repeat(1);
+ /// }
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// fn main() {
+ /// let x = String::from("hello world").clone();
+ /// }
+ /// ```
+ #[clippy::version = "1.47.0"]
+ pub REPEAT_ONCE,
+ complexity,
+ "using `.repeat(1)` instead of `String.clone()`, `str.to_string()` or `slice.to_vec()` "
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// When sorting primitive values (integers, bools, chars, as well
+ /// as arrays, slices, and tuples of such items), it is typically better to
+ /// use an unstable sort than a stable sort.
+ ///
+ /// ### Why is this bad?
+ /// Typically, using a stable sort consumes more memory and cpu cycles.
+ /// Because values which compare equal are identical, preserving their
+ /// relative order (the guarantee that a stable sort provides) means
+ /// nothing, while the extra costs still apply.
+ ///
+ /// ### Known problems
+ ///
+ /// As pointed out in
+ /// [issue #8241](https://github.com/rust-lang/rust-clippy/issues/8241),
+ /// a stable sort can instead be significantly faster for certain scenarios
+ /// (eg. when a sorted vector is extended with new data and resorted).
+ ///
+ /// For more information and benchmarking results, please refer to the
+ /// issue linked above.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let mut vec = vec![2, 1, 3];
+ /// vec.sort();
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// let mut vec = vec![2, 1, 3];
+ /// vec.sort_unstable();
+ /// ```
+ #[clippy::version = "1.47.0"]
+ pub STABLE_SORT_PRIMITIVE,
+ pedantic,
+ "use of sort() when sort_unstable() is equivalent"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Detects `().hash(_)`.
+ ///
+ /// ### Why is this bad?
+ /// Hashing a unit value doesn't do anything as the implementation of `Hash` for `()` is a no-op.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # use std::hash::Hash;
+ /// # use std::collections::hash_map::DefaultHasher;
+ /// # enum Foo { Empty, WithValue(u8) }
+ /// # use Foo::*;
+ /// # let mut state = DefaultHasher::new();
+ /// # let my_enum = Foo::Empty;
+ /// match my_enum {
+ /// Empty => ().hash(&mut state),
+ /// WithValue(x) => x.hash(&mut state),
+ /// }
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// # use std::hash::Hash;
+ /// # use std::collections::hash_map::DefaultHasher;
+ /// # enum Foo { Empty, WithValue(u8) }
+ /// # use Foo::*;
+ /// # let mut state = DefaultHasher::new();
+ /// # let my_enum = Foo::Empty;
+ /// match my_enum {
+ /// Empty => 0_u8.hash(&mut state),
+ /// WithValue(x) => x.hash(&mut state),
+ /// }
+ /// ```
+ #[clippy::version = "1.58.0"]
+ pub UNIT_HASH,
+ correctness,
+ "hashing a unit value, which does nothing"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Detects uses of `Vec::sort_by` passing in a closure
+ /// which compares the two arguments, either directly or indirectly.
+ ///
+ /// ### Why is this bad?
+ /// It is more clear to use `Vec::sort_by_key` (or `Vec::sort` if
+ /// possible) than to use `Vec::sort_by` and a more complicated
+ /// closure.
+ ///
+ /// ### Known problems
+ /// If the suggested `Vec::sort_by_key` uses Reverse and it isn't already
+ /// imported by a use statement, then it will need to be added manually.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # struct A;
+ /// # impl A { fn foo(&self) {} }
+ /// # let mut vec: Vec<A> = Vec::new();
+ /// vec.sort_by(|a, b| a.foo().cmp(&b.foo()));
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// # struct A;
+ /// # impl A { fn foo(&self) {} }
+ /// # let mut vec: Vec<A> = Vec::new();
+ /// vec.sort_by_key(|a| a.foo());
+ /// ```
+ #[clippy::version = "1.46.0"]
+ pub UNNECESSARY_SORT_BY,
+ complexity,
+ "Use of `Vec::sort_by` when `Vec::sort_by_key` or `Vec::sort` would be clearer"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Finds occurrences of `Vec::resize(0, an_int)`
+ ///
+ /// ### Why is this bad?
+ /// This is probably an argument inversion mistake.
+ ///
+ /// ### Example
+ /// ```rust
+ /// vec!(1, 2, 3, 4, 5).resize(0, 5)
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// vec!(1, 2, 3, 4, 5).clear()
+ /// ```
+ #[clippy::version = "1.46.0"]
+ pub VEC_RESIZE_TO_ZERO,
+ correctness,
+ "emptying a vector with `resize(0, an_int)` instead of `clear()` is probably an argument inversion mistake"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for use of File::read_to_end and File::read_to_string.
+ ///
+ /// ### Why is this bad?
+ /// `fs::{read, read_to_string}` provide the same functionality when `buf` is empty with fewer imports and no intermediate values.
+ /// See also: [fs::read docs](https://doc.rust-lang.org/std/fs/fn.read.html), [fs::read_to_string docs](https://doc.rust-lang.org/std/fs/fn.read_to_string.html)
+ ///
+ /// ### Example
+ /// ```rust,no_run
+ /// # use std::io::Read;
+ /// # use std::fs::File;
+ /// let mut f = File::open("foo.txt").unwrap();
+ /// let mut bytes = Vec::new();
+ /// f.read_to_end(&mut bytes).unwrap();
+ /// ```
+ /// Can be written more concisely as
+ /// ```rust,no_run
+ /// # use std::fs;
+ /// let mut bytes = fs::read("foo.txt").unwrap();
+ /// ```
+ #[clippy::version = "1.44.0"]
+ pub VERBOSE_FILE_READS,
+ restriction,
+ "use of `File::read_to_end` or `File::read_to_string`"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ ///
+ /// Checks for iterating a map (`HashMap` or `BTreeMap`) and
+ /// ignoring either the keys or values.
+ ///
+ /// ### Why is this bad?
+ ///
+ /// Readability. There are `keys` and `values` methods that
+ /// can be used to express that we only need the keys or the values.
+ ///
+ /// ### Example
+ ///
+ /// ```
+ /// # use std::collections::HashMap;
+ /// let map: HashMap<u32, u32> = HashMap::new();
+ /// let values = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+ /// ```
+ ///
+ /// Use instead:
+ /// ```
+ /// # use std::collections::HashMap;
+ /// let map: HashMap<u32, u32> = HashMap::new();
+ /// let values = map.values().collect::<Vec<_>>();
+ /// ```
+ #[clippy::version = "1.66.0"]
+ pub ITER_KV_MAP,
+ complexity,
+ "iterating on map using `iter` when `keys` or `values` would do"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ ///
+ /// Checks an argument of `seek` method of `Seek` trait
+ /// and if it start seek from `SeekFrom::Current(0)`, suggests `stream_position` instead.
+ ///
+ /// ### Why is this bad?
+ ///
+ /// Readability. Use dedicated method.
+ ///
+ /// ### Example
+ ///
+ /// ```rust,no_run
+ /// use std::fs::File;
+ /// use std::io::{self, Write, Seek, SeekFrom};
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::create("foo.txt")?;
+ /// f.write_all(b"Hello")?;
+ /// eprintln!("Written {} bytes", f.seek(SeekFrom::Current(0))?);
+ ///
+ /// Ok(())
+ /// }
+ /// ```
+ /// Use instead:
+ /// ```rust,no_run
+ /// use std::fs::File;
+ /// use std::io::{self, Write, Seek, SeekFrom};
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::create("foo.txt")?;
+ /// f.write_all(b"Hello")?;
+ /// eprintln!("Written {} bytes", f.stream_position()?);
+ ///
+ /// Ok(())
+ /// }
+ /// ```
+ #[clippy::version = "1.66.0"]
+ pub SEEK_FROM_CURRENT,
+ complexity,
+ "use dedicated method for seek from current position"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ ///
+ /// Checks for jumps to the start of a stream that implements `Seek`
+ /// and uses the `seek` method providing `Start` as parameter.
+ ///
+ /// ### Why is this bad?
+ ///
+ /// Readability. There is a specific method that was implemented for
+ /// this exact scenario.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # use std::io;
+ /// fn foo<T: io::Seek>(t: &mut T) {
+ /// t.seek(io::SeekFrom::Start(0));
+ /// }
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// # use std::io;
+ /// fn foo<T: io::Seek>(t: &mut T) {
+ /// t.rewind();
+ /// }
+ /// ```
+ #[clippy::version = "1.66.0"]
+ pub SEEK_TO_START_INSTEAD_OF_REWIND,
+ complexity,
+ "jumping to the start of stream using `seek` method"
+}
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for functions collecting an iterator when collect
+ /// is not needed.
+ ///
+ /// ### Why is this bad?
+ /// `collect` causes the allocation of a new data structure,
+ /// when this allocation may not be needed.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # let iterator = vec![1].into_iter();
+ /// let len = iterator.clone().collect::<Vec<_>>().len();
+ /// // should be
+ /// let len = iterator.count();
+ /// ```
+ #[clippy::version = "1.30.0"]
+ pub NEEDLESS_COLLECT,
+ nursery,
+ "collecting an iterator when collect is not needed"
+}
+
+pub struct Methods {
avoid_breaking_exported_api: bool,
- msrv: Option<RustcVersion>,
+ msrv: Msrv,
+ allow_expect_in_tests: bool,
+ allow_unwrap_in_tests: bool,
}
impl Methods {
#[must_use]
- pub fn new(avoid_breaking_exported_api: bool, msrv: Option<RustcVersion>) -> Self {
+ pub fn new(
+ avoid_breaking_exported_api: bool,
+ msrv: Msrv,
+ allow_expect_in_tests: bool,
+ allow_unwrap_in_tests: bool,
+ ) -> Self {
Self {
avoid_breaking_exported_api,
msrv,
+ allow_expect_in_tests,
+ allow_unwrap_in_tests,
}
}
}
OPTION_MAP_OR_NONE,
BIND_INSTEAD_OF_MAP,
OR_FUN_CALL,
+ OR_THEN_UNWRAP,
EXPECT_FUN_CALL,
CHARS_NEXT_CMP,
CHARS_LAST_CMP,
CLONE_ON_COPY,
CLONE_ON_REF_PTR,
CLONE_DOUBLE_REF,
+ COLLAPSIBLE_STR_REPLACE,
+ ITER_OVEREAGER_CLONED,
CLONED_INSTEAD_OF_COPIED,
FLAT_MAP_OPTION,
INEFFICIENT_TO_STRING,
BYTES_NTH,
ITER_SKIP_NEXT,
GET_UNWRAP,
+ GET_LAST_WITH_LEN,
STRING_EXTEND_CHARS,
ITER_CLONED_COLLECT,
+ ITER_WITH_DRAIN,
USELESS_ASREF,
UNNECESSARY_FOLD,
UNNECESSARY_FILTER_MAP,
+ UNNECESSARY_FIND_MAP,
INTO_ITER_ON_REF,
SUSPICIOUS_MAP,
UNINIT_ASSUMED_INIT,
FROM_ITER_INSTEAD_OF_COLLECT,
INSPECT_FOR_EACH,
IMPLICIT_CLONE,
+ SUSPICIOUS_TO_OWNED,
SUSPICIOUS_SPLITN,
MANUAL_STR_REPEAT,
- EXTEND_WITH_DRAIN
+ EXTEND_WITH_DRAIN,
+ MANUAL_SPLIT_ONCE,
+ NEEDLESS_SPLITN,
+ UNNECESSARY_TO_OWNED,
+ UNNECESSARY_JOIN,
+ ERR_EXPECT,
+ NEEDLESS_OPTION_AS_DEREF,
+ IS_DIGIT_ASCII_RADIX,
+ NEEDLESS_OPTION_TAKE,
+ NO_EFFECT_REPLACE,
+ OBFUSCATED_IF_ELSE,
+ ITER_ON_SINGLE_ITEMS,
+ ITER_ON_EMPTY_COLLECTIONS,
+ NAIVE_BYTECOUNT,
+ BYTES_COUNT_TO_LEN,
+ CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
+ GET_FIRST,
+ MANUAL_OK_OR,
+ MAP_CLONE,
+ MAP_ERR_IGNORE,
+ MUT_MUTEX_LOCK,
+ NONSENSICAL_OPEN_OPTIONS,
+ PATH_BUF_PUSH_OVERWRITE,
+ RANGE_ZIP_WITH_LEN,
+ REPEAT_ONCE,
+ STABLE_SORT_PRIMITIVE,
+ UNIT_HASH,
+ UNNECESSARY_SORT_BY,
+ VEC_RESIZE_TO_ZERO,
+ VERBOSE_FILE_READS,
+ ITER_KV_MAP,
+ SEEK_FROM_CURRENT,
+ SEEK_TO_START_INSTEAD_OF_REWIND,
+ NEEDLESS_COLLECT,
]);
/// Extracts a method call name, args, and `Span` of the method name.
-fn method_call<'tcx>(recv: &'tcx hir::Expr<'tcx>) -> Option<(SymbolStr, &'tcx [hir::Expr<'tcx>], Span)> {
- if let ExprKind::MethodCall(path, span, args, _) = recv.kind {
- if !args.iter().any(|e| e.span.from_expansion()) {
- return Some((path.ident.name.as_str(), args, span));
+fn method_call<'tcx>(
+ recv: &'tcx hir::Expr<'tcx>,
+) -> Option<(&'tcx str, &'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>], Span, Span)> {
+ if let ExprKind::MethodCall(path, receiver, args, call_span) = recv.kind {
+ if !args.iter().any(|e| e.span.from_expansion()) && !receiver.span.from_expansion() {
+ let name = path.ident.name.as_str();
+ return Some((name, receiver, args, path.ident.span, call_span));
}
}
None
}
-/// Same as `method_call` but the `SymbolStr` is dereferenced into a temporary `&str`
-macro_rules! method_call {
- ($expr:expr) => {
- method_call($expr)
- .as_ref()
- .map(|&(ref name, args, span)| (&**name, args, span))
- };
-}
-
impl<'tcx> LateLintPass<'tcx> for Methods {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
- if in_macro(expr.span) {
+ if expr.span.from_expansion() {
return;
}
- check_methods(cx, expr, self.msrv.as_ref());
+ self.check_methods(cx, expr);
match expr.kind {
hir::ExprKind::Call(func, args) => {
from_iter_instead_of_collect::check(cx, expr, args, func);
},
- hir::ExprKind::MethodCall(method_call, ref method_span, args, _) => {
- or_fun_call::check(cx, expr, *method_span, &method_call.ident.as_str(), args);
- expect_fun_call::check(cx, expr, *method_span, &method_call.ident.as_str(), args);
- clone_on_copy::check(cx, expr, method_call.ident.name, args);
- clone_on_ref_ptr::check(cx, expr, method_call.ident.name, args);
- inefficient_to_string::check(cx, expr, method_call.ident.name, args);
- single_char_add_str::check(cx, expr, args);
- into_iter_on_ref::check(cx, expr, *method_span, method_call.ident.name, args);
- single_char_pattern::check(cx, expr, method_call.ident.name, args);
+ hir::ExprKind::MethodCall(method_call, receiver, args, _) => {
+ let method_span = method_call.ident.span;
+ or_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), receiver, args);
+ expect_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), receiver, args);
+ clone_on_copy::check(cx, expr, method_call.ident.name, receiver, args);
+ clone_on_ref_ptr::check(cx, expr, method_call.ident.name, receiver, args);
+ inefficient_to_string::check(cx, expr, method_call.ident.name, receiver, args);
+ single_char_add_str::check(cx, expr, receiver, args);
+ into_iter_on_ref::check(cx, expr, method_span, method_call.ident.name, receiver);
+ single_char_pattern::check(cx, expr, method_call.ident.name, receiver, args);
+ unnecessary_to_owned::check(cx, expr, method_call.ident.name, receiver, args, &self.msrv);
},
hir::ExprKind::Binary(op, lhs, rhs) if op.node == hir::BinOpKind::Eq || op.node == hir::BinOpKind::Ne => {
let mut info = BinaryExprInfo {
return;
}
let name = impl_item.ident.name.as_str();
- let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id());
+ let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id()).def_id;
let item = cx.tcx.hir().expect_item(parent);
- let self_ty = cx.tcx.type_of(item.def_id);
+ let self_ty = cx.tcx.type_of(item.owner_id);
let implements_trait = matches!(item.kind, hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }));
- if_chain! {
- if let hir::ImplItemKind::Fn(ref sig, id) = impl_item.kind;
- if let Some(first_arg) = iter_input_pats(sig.decl, cx.tcx.hir().body(id)).next();
-
- let method_sig = cx.tcx.fn_sig(impl_item.def_id);
+ if let hir::ImplItemKind::Fn(ref sig, id) = impl_item.kind {
+ let method_sig = cx.tcx.fn_sig(impl_item.owner_id);
let method_sig = cx.tcx.erase_late_bound_regions(method_sig);
-
- let first_arg_ty = &method_sig.inputs().iter().next();
-
- // check conventions w.r.t. conversion method names and predicates
- if let Some(first_arg_ty) = first_arg_ty;
-
- then {
- // if this impl block implements a trait, lint in trait definition instead
- if !implements_trait && cx.access_levels.is_exported(impl_item.def_id) {
- // check missing trait implementations
- for method_config in &TRAIT_METHODS {
- if name == method_config.method_name &&
- sig.decl.inputs.len() == method_config.param_count &&
- method_config.output_type.matches(&sig.decl.output) &&
- method_config.self_kind.matches(cx, self_ty, first_arg_ty) &&
- fn_header_equals(method_config.fn_header, sig.header) &&
- method_config.lifetime_param_cond(impl_item)
- {
- span_lint_and_help(
- cx,
- SHOULD_IMPLEMENT_TRAIT,
- impl_item.span,
- &format!(
- "method `{}` can be confused for the standard trait method `{}::{}`",
- method_config.method_name,
- method_config.trait_name,
- method_config.method_name
- ),
- None,
- &format!(
- "consider implementing the trait `{}` or choosing a less ambiguous method name",
- method_config.trait_name
- )
- );
- }
+ let first_arg_ty_opt = method_sig.inputs().iter().next().copied();
+ // if this impl block implements a trait, lint in trait definition instead
+ if !implements_trait && cx.effective_visibilities.is_exported(impl_item.owner_id.def_id) {
+ // check missing trait implementations
+ for method_config in &TRAIT_METHODS {
+ if name == method_config.method_name
+ && sig.decl.inputs.len() == method_config.param_count
+ && method_config.output_type.matches(&sig.decl.output)
+ // in case there is no first arg, since we already have checked the number of arguments
+ // it's should be always true
+ && first_arg_ty_opt.map_or(true, |first_arg_ty| method_config
+ .self_kind.matches(cx, self_ty, first_arg_ty)
+ )
+ && fn_header_equals(method_config.fn_header, sig.header)
+ && method_config.lifetime_param_cond(impl_item)
+ {
+ span_lint_and_help(
+ cx,
+ SHOULD_IMPLEMENT_TRAIT,
+ impl_item.span,
+ &format!(
+ "method `{}` can be confused for the standard trait method `{}::{}`",
+ method_config.method_name, method_config.trait_name, method_config.method_name
+ ),
+ None,
+ &format!(
+ "consider implementing the trait `{}` or choosing a less ambiguous method name",
+ method_config.trait_name
+ ),
+ );
}
}
+ }
- if sig.decl.implicit_self.has_implicit_self()
+ if sig.decl.implicit_self.has_implicit_self()
&& !(self.avoid_breaking_exported_api
- && cx.access_levels.is_exported(impl_item.def_id))
+ && cx.effective_visibilities.is_exported(impl_item.owner_id.def_id))
+ && let Some(first_arg) = iter_input_pats(sig.decl, cx.tcx.hir().body(id)).next()
+ && let Some(first_arg_ty) = first_arg_ty_opt
{
wrong_self_convention::check(
cx,
- &name,
+ name,
self_ty,
first_arg_ty,
first_arg.pat.span,
false
);
}
- }
}
// if this impl block implements a trait, lint in trait definition instead
if let hir::ImplItemKind::Fn(_, _) = impl_item.kind {
let ret_ty = return_ty(cx, impl_item.hir_id());
- // walk the return type and check for Self (this does not check associated types)
- if let Some(self_adt) = self_ty.ty_adt_def() {
- if contains_adt_constructor(cx.tcx, ret_ty, self_adt) {
- return;
- }
- } else if contains_ty(cx.tcx, ret_ty, self_ty) {
+ if contains_ty_adt_constructor_opaque(cx, ret_ty, self_ty) {
return;
}
- // if return type is impl trait, check the associated types
- if let ty::Opaque(def_id, _) = *ret_ty.kind() {
- // one of the associated types must be Self
- for &(predicate, _span) in cx.tcx.explicit_item_bounds(def_id) {
- if let ty::PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder() {
- // walk the associated type and check for Self
- if let Some(self_adt) = self_ty.ty_adt_def() {
- if contains_adt_constructor(cx.tcx, projection_predicate.ty, self_adt) {
- return;
- }
- } else if contains_ty(cx.tcx, projection_predicate.ty, self_ty) {
- return;
- }
- }
- }
- }
-
- if name == "new" && !TyS::same_type(ret_ty, self_ty) {
+ if name == "new" && ret_ty != self_ty {
span_lint(
cx,
NEW_RET_NO_SELF,
then {
let first_arg_span = first_arg_ty.span;
let first_arg_ty = hir_ty_to_ty(cx.tcx, first_arg_ty);
- let self_ty = TraitRef::identity(cx.tcx, item.def_id.to_def_id()).self_ty();
+ let self_ty = TraitRef::identity(cx.tcx, item.owner_id.to_def_id())
+ .self_ty()
+ .skip_binder();
wrong_self_convention::check(
cx,
- &item.ident.name.as_str(),
+ item.ident.name.as_str(),
self_ty,
first_arg_ty,
first_arg_span,
false,
- true
+ true,
);
}
}
if item.ident.name == sym::new;
if let TraitItemKind::Fn(_, _) = item.kind;
let ret_ty = return_ty(cx, item.hir_id());
- let self_ty = TraitRef::identity(cx.tcx, item.def_id.to_def_id()).self_ty();
- if !contains_ty(cx.tcx, ret_ty, self_ty);
+ let self_ty = TraitRef::identity(cx.tcx, item.owner_id.to_def_id())
+ .self_ty()
+ .skip_binder();
+ if !ret_ty.contains(self_ty);
then {
span_lint(
extract_msrv_attr!(LateContext);
}
-#[allow(clippy::too_many_lines)]
-fn check_methods<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, msrv: Option<&RustcVersion>) {
- if let Some((name, [recv, args @ ..], span)) = method_call!(expr) {
- match (name, args) {
- ("add" | "offset" | "sub" | "wrapping_offset" | "wrapping_add" | "wrapping_sub", [_arg]) => {
- zst_offset::check(cx, expr, recv);
- },
- ("and_then", [arg]) => {
- let biom_option_linted = bind_instead_of_map::OptionAndThenSome::check(cx, expr, recv, arg);
- let biom_result_linted = bind_instead_of_map::ResultAndThenOk::check(cx, expr, recv, arg);
- if !biom_option_linted && !biom_result_linted {
- unnecessary_lazy_eval::check(cx, expr, recv, arg, "and");
- }
- },
- ("as_mut", []) => useless_asref::check(cx, expr, "as_mut", recv),
- ("as_ref", []) => useless_asref::check(cx, expr, "as_ref", recv),
- ("assume_init", []) => uninit_assumed_init::check(cx, expr, recv),
- ("cloned", []) => cloned_instead_of_copied::check(cx, expr, recv, span, msrv),
- ("collect", []) => match method_call!(recv) {
- Some(("cloned", [recv2], _)) => iter_cloned_collect::check(cx, expr, recv2),
- Some(("map", [m_recv, m_arg], _)) => {
- map_collect_result_unit::check(cx, expr, m_recv, m_arg, recv);
+impl Methods {
+ #[allow(clippy::too_many_lines)]
+ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+ if let Some((name, recv, args, span, call_span)) = method_call(expr) {
+ match (name, args) {
+ ("add" | "offset" | "sub" | "wrapping_offset" | "wrapping_add" | "wrapping_sub", [_arg]) => {
+ zst_offset::check(cx, expr, recv);
},
- Some(("take", [take_self_arg, take_arg], _)) => {
- if meets_msrv(msrv, &msrvs::STR_REPEAT) {
- manual_str_repeat::check(cx, expr, recv, take_self_arg, take_arg);
+ ("and_then", [arg]) => {
+ let biom_option_linted = bind_instead_of_map::OptionAndThenSome::check(cx, expr, recv, arg);
+ let biom_result_linted = bind_instead_of_map::ResultAndThenOk::check(cx, expr, recv, arg);
+ if !biom_option_linted && !biom_result_linted {
+ unnecessary_lazy_eval::check(cx, expr, recv, arg, "and");
}
},
- _ => {},
- },
- ("count", []) => match method_call!(recv) {
- Some((name @ ("into_iter" | "iter" | "iter_mut"), [recv2], _)) => {
- iter_count::check(cx, expr, recv2, name);
+ ("as_deref" | "as_deref_mut", []) => {
+ needless_option_as_deref::check(cx, expr, recv, name);
},
- Some(("map", [_, arg], _)) => suspicious_map::check(cx, expr, recv, arg),
- _ => {},
- },
- ("expect", [_]) => match method_call!(recv) {
- Some(("ok", [recv], _)) => ok_expect::check(cx, expr, recv),
- _ => expect_used::check(cx, expr, recv),
- },
- ("extend", [arg]) => {
- string_extend_chars::check(cx, expr, recv, arg);
- extend_with_drain::check(cx, expr, recv, arg);
- },
- ("filter_map", [arg]) => {
- unnecessary_filter_map::check(cx, expr, arg);
- filter_map_identity::check(cx, expr, arg, span);
- },
- ("flat_map", [arg]) => {
- flat_map_identity::check(cx, expr, arg, span);
- flat_map_option::check(cx, expr, arg, span);
- },
- ("flatten", []) => {
- if let Some(("map", [recv, map_arg], _)) = method_call!(recv) {
- map_flatten::check(cx, expr, recv, map_arg);
- }
- },
- ("fold", [init, acc]) => unnecessary_fold::check(cx, expr, init, acc, span),
- ("for_each", [_]) => {
- if let Some(("inspect", [_, _], span2)) = method_call!(recv) {
- inspect_for_each::check(cx, expr, span2);
- }
- },
- ("get_or_insert_with", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "get_or_insert"),
- ("is_file", []) => filetype_is_file::check(cx, expr, recv),
- ("is_none", []) => check_is_some_is_none(cx, expr, recv, false),
- ("is_some", []) => check_is_some_is_none(cx, expr, recv, true),
- ("map", [m_arg]) => {
- if let Some((name, [recv2, args @ ..], span2)) = method_call!(recv) {
- match (name, args) {
- ("as_mut", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, true, msrv),
- ("as_ref", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, false, msrv),
- ("filter", [f_arg]) => {
- filter_map::check(cx, expr, recv2, f_arg, span2, recv, m_arg, span, false);
+ ("as_mut", []) => useless_asref::check(cx, expr, "as_mut", recv),
+ ("as_ref", []) => useless_asref::check(cx, expr, "as_ref", recv),
+ ("assume_init", []) => uninit_assumed_init::check(cx, expr, recv),
+ ("cloned", []) => cloned_instead_of_copied::check(cx, expr, recv, span, &self.msrv),
+ ("collect", []) if is_trait_method(cx, expr, sym::Iterator) => {
+ needless_collect::check(cx, span, expr, recv, call_span);
+ match method_call(recv) {
+ Some((name @ ("cloned" | "copied"), recv2, [], _, _)) => {
+ iter_cloned_collect::check(cx, name, expr, recv2);
+ },
+ Some(("map", m_recv, [m_arg], _, _)) => {
+ map_collect_result_unit::check(cx, expr, m_recv, m_arg);
+ },
+ Some(("take", take_self_arg, [take_arg], _, _)) => {
+ if self.msrv.meets(msrvs::STR_REPEAT) {
+ manual_str_repeat::check(cx, expr, recv, take_self_arg, take_arg);
+ }
},
- ("find", [f_arg]) => filter_map::check(cx, expr, recv2, f_arg, span2, recv, m_arg, span, true),
_ => {},
}
- }
- map_identity::check(cx, expr, recv, m_arg, span);
- },
- ("map_or", [def, map]) => option_map_or_none::check(cx, expr, recv, def, map),
- ("next", []) => {
- if let Some((name, [recv, args @ ..], _)) = method_call!(recv) {
- match (name, args) {
- ("filter", [arg]) => filter_next::check(cx, expr, recv, arg),
- ("filter_map", [arg]) => filter_map_next::check(cx, expr, recv, arg, msrv),
- ("iter", []) => iter_next_slice::check(cx, expr, recv),
- ("skip", [arg]) => iter_skip_next::check(cx, expr, recv, arg),
- ("skip_while", [_]) => skip_while_next::check(cx, expr),
+ },
+ ("count", []) if is_trait_method(cx, expr, sym::Iterator) => match method_call(recv) {
+ Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false),
+ Some((name2 @ ("into_iter" | "iter" | "iter_mut"), recv2, [], _, _)) => {
+ iter_count::check(cx, expr, recv2, name2);
+ },
+ Some(("map", _, [arg], _, _)) => suspicious_map::check(cx, expr, recv, arg),
+ Some(("filter", recv2, [arg], _, _)) => bytecount::check(cx, expr, recv2, arg),
+ Some(("bytes", recv2, [], _, _)) => bytes_count_to_len::check(cx, expr, recv, recv2),
+ _ => {},
+ },
+ ("drain", [arg]) => {
+ iter_with_drain::check(cx, expr, recv, span, arg);
+ },
+ ("ends_with", [arg]) => {
+ if let ExprKind::MethodCall(.., span) = expr.kind {
+ case_sensitive_file_extension_comparisons::check(cx, expr, span, recv, arg);
+ }
+ },
+ ("expect", [_]) => match method_call(recv) {
+ Some(("ok", recv, [], _, _)) => ok_expect::check(cx, expr, recv),
+ Some(("err", recv, [], err_span, _)) => err_expect::check(cx, expr, recv, span, err_span, &self.msrv),
+ _ => expect_used::check(cx, expr, recv, false, self.allow_expect_in_tests),
+ },
+ ("expect_err", [_]) => expect_used::check(cx, expr, recv, true, self.allow_expect_in_tests),
+ ("extend", [arg]) => {
+ string_extend_chars::check(cx, expr, recv, arg);
+ extend_with_drain::check(cx, expr, recv, arg);
+ },
+ ("filter_map", [arg]) => {
+ unnecessary_filter_map::check(cx, expr, arg, name);
+ filter_map_identity::check(cx, expr, arg, span);
+ },
+ ("find_map", [arg]) => {
+ unnecessary_filter_map::check(cx, expr, arg, name);
+ },
+ ("flat_map", [arg]) => {
+ flat_map_identity::check(cx, expr, arg, span);
+ flat_map_option::check(cx, expr, arg, span);
+ },
+ ("flatten", []) => match method_call(recv) {
+ Some(("map", recv, [map_arg], map_span, _)) => map_flatten::check(cx, expr, recv, map_arg, map_span),
+ Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true),
+ _ => {},
+ },
+ ("fold", [init, acc]) => unnecessary_fold::check(cx, expr, init, acc, span),
+ ("for_each", [_]) => {
+ if let Some(("inspect", _, [_], span2, _)) = method_call(recv) {
+ inspect_for_each::check(cx, expr, span2);
+ }
+ },
+ ("get", [arg]) => {
+ get_first::check(cx, expr, recv, arg);
+ get_last_with_len::check(cx, expr, recv, arg);
+ },
+ ("get_or_insert_with", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "get_or_insert"),
+ ("hash", [arg]) => {
+ unit_hash::check(cx, expr, recv, arg);
+ },
+ ("is_file", []) => filetype_is_file::check(cx, expr, recv),
+ ("is_digit", [radix]) => is_digit_ascii_radix::check(cx, expr, recv, radix, &self.msrv),
+ ("is_none", []) => check_is_some_is_none(cx, expr, recv, false),
+ ("is_some", []) => check_is_some_is_none(cx, expr, recv, true),
+ ("iter" | "iter_mut" | "into_iter", []) => {
+ iter_on_single_or_empty_collections::check(cx, expr, name, recv);
+ },
+ ("join", [join_arg]) => {
+ if let Some(("collect", _, _, span, _)) = method_call(recv) {
+ unnecessary_join::check(cx, expr, recv, join_arg, span);
+ }
+ },
+ ("last", []) | ("skip", [_]) => {
+ if let Some((name2, recv2, args2, _span2, _)) = method_call(recv) {
+ if let ("cloned", []) = (name2, args2) {
+ iter_overeager_cloned::check(cx, expr, recv, recv2, false, false);
+ }
+ }
+ },
+ ("lock", []) => {
+ mut_mutex_lock::check(cx, expr, recv, span);
+ },
+ (name @ ("map" | "map_err"), [m_arg]) => {
+ if name == "map" {
+ map_clone::check(cx, expr, recv, m_arg, &self.msrv);
+ if let Some((map_name @ ("iter" | "into_iter"), recv2, _, _, _)) = method_call(recv) {
+ iter_kv_map::check(cx, map_name, expr, recv2, m_arg);
+ }
+ } else {
+ map_err_ignore::check(cx, expr, m_arg);
+ }
+ if let Some((name, recv2, args, span2,_)) = method_call(recv) {
+ match (name, args) {
+ ("as_mut", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, true, &self.msrv),
+ ("as_ref", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, false, &self.msrv),
+ ("filter", [f_arg]) => {
+ filter_map::check(cx, expr, recv2, f_arg, span2, recv, m_arg, span, false);
+ },
+ ("find", [f_arg]) => {
+ filter_map::check(cx, expr, recv2, f_arg, span2, recv, m_arg, span, true);
+ },
+ _ => {},
+ }
+ }
+ map_identity::check(cx, expr, recv, m_arg, name, span);
+ },
+ ("map_or", [def, map]) => {
+ option_map_or_none::check(cx, expr, recv, def, map);
+ manual_ok_or::check(cx, expr, recv, def, map);
+ },
+ ("next", []) => {
+ if let Some((name2, recv2, args2, _, _)) = method_call(recv) {
+ match (name2, args2) {
+ ("cloned", []) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),
+ ("filter", [arg]) => filter_next::check(cx, expr, recv2, arg),
+ ("filter_map", [arg]) => filter_map_next::check(cx, expr, recv2, arg, &self.msrv),
+ ("iter", []) => iter_next_slice::check(cx, expr, recv2),
+ ("skip", [arg]) => iter_skip_next::check(cx, expr, recv2, arg),
+ ("skip_while", [_]) => skip_while_next::check(cx, expr),
+ _ => {},
+ }
+ }
+ },
+ ("nth", [n_arg]) => match method_call(recv) {
+ Some(("bytes", recv2, [], _, _)) => bytes_nth::check(cx, expr, recv2, n_arg),
+ Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),
+ Some(("iter", recv2, [], _, _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false),
+ Some(("iter_mut", recv2, [], _, _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true),
+ _ => iter_nth_zero::check(cx, expr, recv, n_arg),
+ },
+ ("ok_or_else", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "ok_or"),
+ ("open", [_]) => {
+ open_options::check(cx, expr, recv);
+ },
+ ("or_else", [arg]) => {
+ if !bind_instead_of_map::ResultOrElseErrInfo::check(cx, expr, recv, arg) {
+ unnecessary_lazy_eval::check(cx, expr, recv, arg, "or");
+ }
+ },
+ ("push", [arg]) => {
+ path_buf_push_overwrite::check(cx, expr, arg);
+ },
+ ("read_to_end", [_]) => {
+ verbose_file_reads::check(cx, expr, recv, verbose_file_reads::READ_TO_END_MSG);
+ },
+ ("read_to_string", [_]) => {
+ verbose_file_reads::check(cx, expr, recv, verbose_file_reads::READ_TO_STRING_MSG);
+ },
+ ("repeat", [arg]) => {
+ repeat_once::check(cx, expr, recv, arg);
+ },
+ (name @ ("replace" | "replacen"), [arg1, arg2] | [arg1, arg2, _]) => {
+ no_effect_replace::check(cx, expr, arg1, arg2);
+
+ // Check for repeated `str::replace` calls to perform `collapsible_str_replace` lint
+ if self.msrv.meets(msrvs::PATTERN_TRAIT_CHAR_ARRAY)
+ && name == "replace"
+ && let Some(("replace", ..)) = method_call(recv)
+ {
+ collapsible_str_replace::check(cx, expr, arg1, arg2);
+ }
+ },
+ ("resize", [count_arg, default_arg]) => {
+ vec_resize_to_zero::check(cx, expr, count_arg, default_arg, span);
+ },
+ ("seek", [arg]) => {
+ if self.msrv.meets(msrvs::SEEK_FROM_CURRENT) {
+ seek_from_current::check(cx, expr, recv, arg);
+ }
+ if self.msrv.meets(msrvs::SEEK_REWIND) {
+ seek_to_start_instead_of_rewind::check(cx, expr, recv, arg, span);
+ }
+ },
+ ("sort", []) => {
+ stable_sort_primitive::check(cx, expr, recv);
+ },
+ ("sort_by", [arg]) => {
+ unnecessary_sort_by::check(cx, expr, recv, arg, false);
+ },
+ ("sort_unstable_by", [arg]) => {
+ unnecessary_sort_by::check(cx, expr, recv, arg, true);
+ },
+ ("splitn" | "rsplitn", [count_arg, pat_arg]) => {
+ if let Some((Constant::Int(count), _)) = constant(cx, cx.typeck_results(), count_arg) {
+ suspicious_splitn::check(cx, name, expr, recv, count);
+ str_splitn::check(cx, name, expr, recv, pat_arg, count, &self.msrv);
+ }
+ },
+ ("splitn_mut" | "rsplitn_mut", [count_arg, _]) => {
+ if let Some((Constant::Int(count), _)) = constant(cx, cx.typeck_results(), count_arg) {
+ suspicious_splitn::check(cx, name, expr, recv, count);
+ }
+ },
+ ("step_by", [arg]) => iterator_step_by_zero::check(cx, expr, arg),
+ ("take", [_arg]) => {
+ if let Some((name2, recv2, args2, _span2, _)) = method_call(recv) {
+ if let ("cloned", []) = (name2, args2) {
+ iter_overeager_cloned::check(cx, expr, recv, recv2, false, false);
+ }
+ }
+ },
+ ("take", []) => needless_option_take::check(cx, expr, recv),
+ ("then", [arg]) => {
+ if !self.msrv.meets(msrvs::BOOL_THEN_SOME) {
+ return;
+ }
+ unnecessary_lazy_eval::check(cx, expr, recv, arg, "then_some");
+ },
+ ("to_owned", []) => {
+ if !suspicious_to_owned::check(cx, expr, recv) {
+ implicit_clone::check(cx, name, expr, recv);
+ }
+ },
+ ("to_os_string" | "to_path_buf" | "to_vec", []) => {
+ implicit_clone::check(cx, name, expr, recv);
+ },
+ ("unwrap", []) => {
+ match method_call(recv) {
+ Some(("get", recv, [get_arg], _, _)) => {
+ get_unwrap::check(cx, expr, recv, get_arg, false);
+ },
+ Some(("get_mut", recv, [get_arg], _, _)) => {
+ get_unwrap::check(cx, expr, recv, get_arg, true);
+ },
+ Some(("or", recv, [or_arg], or_span, _)) => {
+ or_then_unwrap::check(cx, expr, recv, or_arg, or_span);
+ },
_ => {},
}
- }
- },
- ("nth", [n_arg]) => match method_call!(recv) {
- Some(("bytes", [recv2], _)) => bytes_nth::check(cx, expr, recv2, n_arg),
- Some(("iter", [recv2], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false),
- Some(("iter_mut", [recv2], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true),
- _ => iter_nth_zero::check(cx, expr, recv, n_arg),
- },
- ("ok_or_else", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "ok_or"),
- ("or_else", [arg]) => {
- if !bind_instead_of_map::ResultOrElseErrInfo::check(cx, expr, recv, arg) {
- unnecessary_lazy_eval::check(cx, expr, recv, arg, "or");
- }
- },
- ("splitn" | "splitn_mut" | "rsplitn" | "rsplitn_mut", [count_arg, _]) => {
- suspicious_splitn::check(cx, name, expr, recv, count_arg);
- },
- ("step_by", [arg]) => iterator_step_by_zero::check(cx, expr, arg),
- ("to_os_string" | "to_owned" | "to_path_buf" | "to_vec", []) => {
- implicit_clone::check(cx, name, expr, recv, span);
- },
- ("unwrap", []) => match method_call!(recv) {
- Some(("get", [recv, get_arg], _)) => get_unwrap::check(cx, expr, recv, get_arg, false),
- Some(("get_mut", [recv, get_arg], _)) => get_unwrap::check(cx, expr, recv, get_arg, true),
- _ => unwrap_used::check(cx, expr, recv),
- },
- ("unwrap_or", [u_arg]) => match method_call!(recv) {
- Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), [lhs, rhs], _)) => {
- manual_saturating_arithmetic::check(cx, expr, lhs, rhs, u_arg, &arith["checked_".len()..]);
+ unwrap_used::check(cx, expr, recv, false, self.allow_unwrap_in_tests);
},
- Some(("map", [m_recv, m_arg], span)) => {
- option_map_unwrap_or::check(cx, expr, m_recv, m_arg, recv, u_arg, span);
+ ("unwrap_err", []) => unwrap_used::check(cx, expr, recv, true, self.allow_unwrap_in_tests),
+ ("unwrap_or", [u_arg]) => match method_call(recv) {
+ Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), lhs, [rhs], _, _)) => {
+ manual_saturating_arithmetic::check(cx, expr, lhs, rhs, u_arg, &arith["checked_".len()..]);
+ },
+ Some(("map", m_recv, [m_arg], span, _)) => {
+ option_map_unwrap_or::check(cx, expr, m_recv, m_arg, recv, u_arg, span);
+ },
+ Some(("then_some", t_recv, [t_arg], _, _)) => {
+ obfuscated_if_else::check(cx, expr, t_recv, t_arg, u_arg);
+ },
+ _ => {},
},
- _ => {},
- },
- ("unwrap_or_else", [u_arg]) => match method_call!(recv) {
- Some(("map", [recv, map_arg], _)) if map_unwrap_or::check(cx, expr, recv, map_arg, u_arg, msrv) => {},
- _ => {
- unwrap_or_else_default::check(cx, expr, recv, u_arg);
- unnecessary_lazy_eval::check(cx, expr, recv, u_arg, "unwrap_or");
+ ("unwrap_or_else", [u_arg]) => match method_call(recv) {
+ Some(("map", recv, [map_arg], _, _))
+ if map_unwrap_or::check(cx, expr, recv, map_arg, u_arg, &self.msrv) => {},
+ _ => {
+ unwrap_or_else_default::check(cx, expr, recv, u_arg);
+ unnecessary_lazy_eval::check(cx, expr, recv, u_arg, "unwrap_or");
+ },
},
- },
- _ => {},
+ ("zip", [arg]) => {
+ if let ExprKind::MethodCall(name, iter_recv, [], _) = recv.kind
+ && name.ident.name == sym::iter
+ {
+ range_zip_with_len::check(cx, expr, iter_recv, arg);
+ }
+ },
+ _ => {},
+ }
}
}
}
fn check_is_some_is_none(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, is_some: bool) {
- if let Some((name @ ("find" | "position" | "rposition"), [f_recv, arg], span)) = method_call!(recv) {
+ if let Some((name @ ("find" | "position" | "rposition"), f_recv, [arg], span, _)) = method_call(recv) {
search_is_some::check(cx, expr, name, is_some, f_recv, arg, recv, span);
}
}
ShouldImplTraitCase::new("std::borrow::BorrowMut", "borrow_mut", 1, FN_HEADER, SelfKind::RefMut, OutType::Ref, true),
ShouldImplTraitCase::new("std::clone::Clone", "clone", 1, FN_HEADER, SelfKind::Ref, OutType::Any, true),
ShouldImplTraitCase::new("std::cmp::Ord", "cmp", 2, FN_HEADER, SelfKind::Ref, OutType::Any, true),
- // FIXME: default doesn't work
ShouldImplTraitCase::new("std::default::Default", "default", 0, FN_HEADER, SelfKind::No, OutType::Any, true),
ShouldImplTraitCase::new("std::ops::Deref", "deref", 1, FN_HEADER, SelfKind::Ref, OutType::Ref, true),
ShouldImplTraitCase::new("std::ops::DerefMut", "deref_mut", 1, FN_HEADER, SelfKind::RefMut, OutType::Ref, true),
ShouldImplTraitCase::new("std::ops::Sub", "sub", 2, FN_HEADER, SelfKind::Value, OutType::Any, true),
];
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
enum SelfKind {
Value,
Ref,
RefMut,
- No,
+ No, // When we want the first argument type to be different than `Self`
}
impl SelfKind {
fn matches<'a>(self, cx: &LateContext<'a>, parent_ty: Ty<'a>, ty: Ty<'a>) -> bool {
- fn matches_value<'a>(cx: &LateContext<'a>, parent_ty: Ty<'_>, ty: Ty<'_>) -> bool {
+ fn matches_value<'a>(cx: &LateContext<'a>, parent_ty: Ty<'a>, ty: Ty<'a>) -> bool {
if ty == parent_ty {
true
} else if ty.is_box() {
return m == mutability && t == parent_ty;
}
- let trait_path = match mutability {
- hir::Mutability::Not => &paths::ASREF_TRAIT,
- hir::Mutability::Mut => &paths::ASMUT_TRAIT,
+ let trait_sym = match mutability {
+ hir::Mutability::Not => sym::AsRef,
+ hir::Mutability::Mut => sym::AsMut,
};
- let trait_def_id = match get_trait_def_id(cx, trait_path) {
- Some(did) => did,
- None => return false,
+ let Some(trait_def_id) = cx.tcx.get_diagnostic_item(trait_sym) else {
+ return false
};
implements_trait(cx, ty, trait_def_id, &[parent_ty.into()])
}
+ fn matches_none<'a>(cx: &LateContext<'a>, parent_ty: Ty<'a>, ty: Ty<'a>) -> bool {
+ !matches_value(cx, parent_ty, ty)
+ && !matches_ref(cx, hir::Mutability::Not, parent_ty, ty)
+ && !matches_ref(cx, hir::Mutability::Mut, parent_ty, ty)
+ }
+
match self {
Self::Value => matches_value(cx, parent_ty, ty),
Self::Ref => matches_ref(cx, hir::Mutability::Not, parent_ty, ty) || ty == parent_ty && is_copy(cx, ty),
Self::RefMut => matches_ref(cx, hir::Mutability::Mut, parent_ty, ty),
- Self::No => ty != parent_ty,
+ Self::No => matches_none(cx, parent_ty, ty),
}
}
(Self::Unit, &hir::FnRetTy::Return(ty)) if is_unit(ty) => true,
(Self::Bool, &hir::FnRetTy::Return(ty)) if is_bool(ty) => true,
(Self::Any, &hir::FnRetTy::Return(ty)) if !is_unit(ty) => true,
- (Self::Ref, &hir::FnRetTy::Return(ty)) => matches!(ty.kind, hir::TyKind::Rptr(_, _)),
+ (Self::Ref, &hir::FnRetTy::Return(ty)) => matches!(ty.kind, hir::TyKind::Ref(_, _)),
_ => false,
}
}
}
-fn is_bool(ty: &hir::Ty<'_>) -> bool {
- if let hir::TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
- matches!(path.res, Res::PrimTy(PrimTy::Bool))
- } else {
- false
- }
-}
-
fn fn_header_equals(expected: hir::FnHeader, actual: hir::FnHeader) -> bool {
expected.constness == actual.constness
&& expected.unsafety == actual.unsafety
projects / rustc.git / blobdiff