1.83.0.txt (30906B)
1 2 Available lint options: 3 -W <foo> Warn about <foo> 4 -A <foo> Allow <foo> 5 -D <foo> Deny <foo> 6 -F <foo> Forbid <foo> (deny <foo> and all attempts to override) 7 8 9 Lint checks provided by rustc: 10 11 name default meaning 12 ---- ------- ------- 13 absolute-paths-not-starting-with-crate allow fully qualified paths that start with a module name instead of `crate`, `self`, or an extern crate name 14 ambiguous-negative-literals allow ambiguous negative literals operations 15 closure-returning-async-block allow closure that returns `async {}` could be rewritten as an async closure 16 deprecated-in-future allow detects use of items that will be deprecated in a future version 17 deprecated-safe-2024 allow detects unsafe functions being used as safe functions 18 edition-2024-expr-fragment-specifier allow The `expr` fragment specifier will accept more expressions in the 2024 edition. To keep the existing behavior, use the `expr_2021` fragment specifier. 19 elided-lifetimes-in-paths allow hidden lifetime parameters in types are deprecated 20 explicit-outlives-requirements allow outlives requirements can be inferred 21 ffi-unwind-calls allow call to foreign functions or function pointers with FFI-unwind ABI 22 fuzzy-provenance-casts allow a fuzzy integer to pointer cast is used 23 if-let-rescope allow `if let` assigns a shorter lifetime to temporary values being pattern-matched against in Edition 2024 and rewriting in `match` is an option to preserve the semantics up to Edition 2021 24 impl-trait-overcaptures allow `impl Trait` will capture more lifetimes than possibly intended in edition 2024 25 keyword-idents-2018 allow detects edition keywords being used as an identifier 26 keyword-idents-2024 allow detects edition keywords being used as an identifier 27 let-underscore-drop allow non-binding let on a type that has a destructor 28 lossy-provenance-casts allow a lossy pointer to integer cast is used 29 macro-use-extern-crate allow the `#[macro_use]` attribute is now deprecated in favor of using macros via the module system 30 meta-variable-misuse allow possible meta-variable misuse at macro definition 31 missing-abi allow No declared ABI for extern declaration 32 missing-copy-implementations allow detects potentially-forgotten implementations of `Copy` 33 missing-debug-implementations allow detects missing implementations of Debug 34 missing-docs allow detects missing documentation for public members 35 missing-unsafe-on-extern allow detects missing unsafe keyword on extern declarations 36 multiple-supertrait-upcastable allow detect when a dyn-compatible trait has multiple supertraits 37 must-not-suspend allow use of a `#[must_not_suspend]` value across a yield point 38 non-ascii-idents allow detects non-ASCII identifiers 39 non-exhaustive-omitted-patterns allow detect when patterns of types marked `non_exhaustive` are missed 40 redundant-imports allow imports that are redundant due to being imported already 41 redundant-lifetimes allow detects lifetime parameters that are redundant because they are equal to some other named lifetime 42 rust-2021-incompatible-closure-captures allow detects closures affected by Rust 2021 changes 43 rust-2021-incompatible-or-patterns allow detects usage of old versions of or-patterns 44 rust-2021-prefixes-incompatible-syntax allow identifiers that will be parsed as a prefix in Rust 2021 45 rust-2021-prelude-collisions allow detects the usage of trait methods which are ambiguous with traits added to the prelude in future editions 46 rust-2024-guarded-string-incompatible-syntax allow will be parsed as a guarded string in Rust 2024 47 rust-2024-incompatible-pat allow detects patterns whose meaning will change in Rust 2024 48 rust-2024-prelude-collisions allow detects the usage of trait methods which are ambiguous with traits added to the prelude in future editions 49 single-use-lifetimes allow detects lifetime parameters that are only used once 50 tail-expr-drop-order allow Detect and warn on significant change in drop order in tail expression location 51 trivial-casts allow detects trivial casts which could be removed 52 trivial-numeric-casts allow detects trivial casts of numeric types which could be removed 53 unit-bindings allow binding is useless because it has the unit `()` type 54 unnameable-types allow effective visibility of a type is larger than the area in which it can be named 55 unqualified-local-imports allow `use` of a local item without leading `self::`, `super::`, or `crate::` 56 unreachable-pub allow `pub` items not reachable from crate root 57 unsafe-attr-outside-unsafe allow detects unsafe attributes outside of unsafe 58 unsafe-code allow usage of `unsafe` code and other potentially unsound constructs 59 unsafe-op-in-unsafe-fn allow unsafe operations in unsafe functions without an explicit unsafe block are deprecated 60 unstable-features allow enabling unstable features 61 unused-crate-dependencies allow crate dependencies that are never used 62 unused-extern-crates allow extern crates that are never used 63 unused-import-braces allow unnecessary braces around an imported item 64 unused-lifetimes allow detects lifetime parameters that are never used 65 unused-macro-rules allow detects macro rules that were not used 66 unused-qualifications allow detects unnecessarily qualified names 67 unused-results allow unused result of an expression in a statement 68 variant-size-differences allow detects enums with widely varying variant sizes 69 ambiguous-glob-imports warn detects certain glob imports that require reporting an ambiguity error 70 ambiguous-glob-reexports warn ambiguous glob re-exports 71 ambiguous-wide-pointer-comparisons warn detects ambiguous wide pointer comparisons 72 anonymous-parameters warn detects anonymous parameters 73 array-into-iter warn detects calling `into_iter` on arrays in Rust 2015 and 2018 74 asm-sub-register warn using only a subset of a register for inline asm inputs 75 async-fn-in-trait warn use of `async fn` in definition of a publicly-reachable trait 76 bad-asm-style warn incorrect use of inline assembly 77 bare-trait-objects warn suggest using `dyn Trait` for trait objects 78 boxed-slice-into-iter warn detects calling `into_iter` on boxed slices in Rust 2015, 2018, and 2021 79 break-with-label-and-loop warn `break` expression with label and unlabeled loop as value expression 80 clashing-extern-declarations warn detects when an extern fn has been declared with the same name but different types 81 coherence-leak-check warn distinct impls distinguished only by the leak-check code 82 confusable-idents warn detects visually confusable pairs between identifiers 83 const-evaluatable-unchecked warn detects a generic constant is used in a type without a emitting a warning 84 const-item-mutation warn detects attempts to mutate a `const` item 85 dead-code warn detect unused, unexported items 86 dependency-on-unit-never-type-fallback warn never type fallback affecting unsafe function calls 87 deprecated warn detects use of deprecated items 88 deprecated-where-clause-location warn deprecated where clause location 89 deref-into-dyn-supertrait warn `Deref` implementation usage with a supertrait trait object for output might be shadowed in the future 90 deref-nullptr warn detects when an null pointer is dereferenced 91 dropping-copy-types warn calls to `std::mem::drop` with a value that implements Copy 92 dropping-references warn calls to `std::mem::drop` with a reference instead of an owned value 93 drop-bounds warn bounds of the form `T: Drop` are most likely incorrect 94 duplicate-macro-attributes warn duplicated attribute 95 dyn-drop warn trait objects of the form `dyn Drop` are useless 96 elided-named-lifetimes warn detects when an elided lifetime gets resolved to be `'static` or some named parameter 97 ellipsis-inclusive-range-patterns warn `...` range patterns are deprecated 98 exported-private-dependencies warn public interface leaks type from a private dependency 99 forbidden-lint-groups warn applying forbid to lint-groups 100 forgetting-copy-types warn calls to `std::mem::forget` with a value that implements Copy 101 forgetting-references warn calls to `std::mem::forget` with a reference instead of an owned value 102 for-loops-over-fallibles warn for-looping over an `Option` or a `Result`, which is more clearly expressed as an `if let` 103 function-item-references warn suggest casting to a function pointer when attempting to take references to function items 104 hidden-glob-reexports warn name introduced by a private item shadows a name introduced by a public glob re-export 105 impl-trait-redundant-captures warn redundant precise-capturing `use<...>` syntax on an `impl Trait` 106 improper-ctypes warn proper use of libc types in foreign modules 107 improper-ctypes-definitions warn proper use of libc types in foreign item definitions 108 incomplete-features warn incomplete features that may function improperly in some or all cases 109 inline-no-sanitize warn detects incompatible use of `#[inline(always)]` and `#[no_sanitize(...)]` 110 internal-features warn internal features are not supposed to be used 111 invalid-from-utf8 warn using a non UTF-8 literal in `std::str::from_utf8` 112 invalid-macro-export-arguments warn "invalid_parameter" isn't a valid argument for `#[macro_export]` 113 invalid-nan-comparisons warn detects invalid floating point NaN comparisons 114 invalid-value warn an invalid value is being created (such as a null reference) 115 irrefutable-let-patterns warn detects irrefutable patterns in `if let` and `while let` statements 116 large-assignments warn detects large moves or copies 117 late-bound-lifetime-arguments warn detects generic lifetime arguments in path segments with late bound lifetime parameters 118 legacy-derive-helpers warn detects derive helper attributes that are used before they are introduced 119 map-unit-fn warn `Iterator::map` call that discard the iterator's values 120 mixed-script-confusables warn detects Unicode scripts whose mixed script confusables codepoints are solely used 121 named-arguments-used-positionally warn named arguments in format used positionally 122 never-type-fallback-flowing-into-unsafe warn never type fallback affecting unsafe function calls 123 non-camel-case-types warn types, variants, traits and type parameters should have camel case names 124 non-contiguous-range-endpoints warn detects off-by-one errors with exclusive range patterns 125 non-fmt-panics warn detect single-argument panic!() invocations in which the argument is not a format string 126 non-local-definitions warn checks for non-local definitions 127 non-shorthand-field-patterns warn using `Struct { x: x }` instead of `Struct { x }` in a pattern 128 non-snake-case warn variables, methods, functions, lifetime parameters and modules should have snake case names 129 non-upper-case-globals warn static constants should have uppercase identifiers 130 noop-method-call warn detects the use of well-known noop methods 131 no-mangle-generic-items warn generic items must be mangled 132 opaque-hidden-inferred-bound warn detects the use of nested `impl Trait` types in associated type bounds that are not general enough 133 out-of-scope-macro-calls warn detects out of scope calls to `macro_rules` in key-value attributes 134 overlapping-range-endpoints warn detects range patterns with overlapping endpoints 135 path-statements warn path statements with no effect 136 private-bounds warn private type in secondary interface of an item 137 private-interfaces warn private type in primary interface of an item 138 ptr-cast-add-auto-to-object warn detects `as` casts from pointers to `dyn Trait` to pointers to `dyn Trait + Auto` 139 ptr-to-integer-transmute-in-consts warn detects pointer to integer transmutes in const functions and associated constants 140 redundant-semicolons warn detects unnecessary trailing semicolons 141 refining-impl-trait-internal warn impl trait in impl method signature does not match trait method signature 142 refining-impl-trait-reachable warn impl trait in impl method signature does not match trait method signature 143 renamed-and-removed-lints warn lints that have been renamed or removed 144 repr-transparent-external-private-fields warn transparent type contains an external ZST that is marked #[non_exhaustive] or contains private fields 145 self-constructor-from-outer-item warn detect unsupported use of `Self` from outer item 146 semicolon-in-expressions-from-macros warn trailing semicolon in macro body used as expression 147 special-module-name warn module declarations for files with a special meaning 148 stable-features warn stable features found in `#[feature]` directive 149 static-mut-refs warn shared references or mutable references of mutable static is discouraged 150 suspicious-double-ref-op warn suspicious call of trait method on `&&T` 151 temporary-cstring-as-ptr warn detects getting the inner pointer of a temporary `CString` 152 trivial-bounds warn these bounds don't depend on an type parameters 153 type-alias-bounds warn bounds in type aliases are not enforced 154 tyvar-behind-raw-pointer warn raw pointer to an inference variable 155 uncommon-codepoints warn detects uncommon Unicode codepoints in identifiers 156 unconditional-recursion warn functions that cannot return without calling themselves 157 uncovered-param-in-projection warn impl contains type parameters that are not covered 158 undefined-naked-function-abi warn undefined naked function ABI 159 unexpected-cfgs warn detects unexpected names and values in `#[cfg]` conditions 160 unfulfilled-lint-expectations warn unfulfilled lint expectation 161 ungated-async-fn-track-caller warn enabling track_caller on an async fn is a no-op unless the async_fn_track_caller feature is enabled 162 uninhabited-static warn uninhabited static 163 unknown-lints warn unrecognized lint attribute 164 unknown-or-malformed-diagnostic-attributes warn unrecognized or malformed diagnostic attribute 165 unnameable-test-items warn detects an item that cannot be named being marked as `#[test_case]` 166 unreachable-code warn detects unreachable code paths 167 unreachable-patterns warn detects unreachable patterns 168 unstable-name-collisions warn detects name collision with an existing but unstable method 169 unstable-syntax-pre-expansion warn unstable syntax can change at any point in the future, causing a hard error! 170 unsupported-calling-conventions warn use of unsupported calling convention 171 unsupported-fn-ptr-calling-conventions warn use of unsupported calling convention for function pointer 172 unused-allocation warn detects unnecessary allocations that can be eliminated 173 unused-assignments warn detect assignments that will never be read 174 unused-associated-type-bounds warn detects unused `Foo = Bar` bounds in `dyn Trait<Foo = Bar>` 175 unused-attributes warn detects attributes that were not used by the compiler 176 unused-braces warn unnecessary braces around an expression 177 unused-comparisons warn comparisons made useless by limits of the types involved 178 unused-doc-comments warn detects doc comments that aren't used by rustdoc 179 unused-features warn unused features found in crate-level `#[feature]` directives 180 unused-imports warn imports that are never used 181 unused-labels warn detects labels that are never used 182 unused-macros warn detects macros that were not used 183 unused-must-use warn unused result of a type flagged as `#[must_use]` 184 unused-mut warn detect mut variables which don't need to be mutable 185 unused-parens warn `if`, `match`, `while` and `return` do not need parentheses 186 unused-unsafe warn unnecessary use of an `unsafe` block 187 unused-variables warn detect variables which are not used in any way 188 useless-ptr-null-checks warn useless checking of non-null-typed pointer 189 warnings warn mass-change the level for lints which produce warnings 190 while-true warn suggest using `loop { }` instead of `while true { }` 191 ambiguous-associated-items deny ambiguous associated items 192 arithmetic-overflow deny arithmetic operation overflows 193 binary-asm-labels deny labels in inline assembly containing only 0 or 1 digits 194 bindings-with-variant-name deny detects pattern bindings with the same name as one of the matched variants 195 cenum-impl-drop-cast deny a C-like enum implementing Drop is cast 196 conflicting-repr-hints deny conflicts between `#[repr(..)]` hints that were previously accepted and used in practice 197 elided-lifetimes-in-associated-constant deny elided lifetimes cannot be used in associated constants in impls 198 enum-intrinsics-non-enums deny detects calls to `core::mem::discriminant` and `core::mem::variant_count` with non-enum types 199 explicit-builtin-cfgs-in-flags deny detects builtin cfgs set via the `--cfg` 200 ill-formed-attribute-input deny ill-formed attribute inputs that were previously accepted and used in practice 201 incomplete-include deny trailing content in included file 202 ineffective-unstable-trait-impl deny detects `#[unstable]` on stable trait implementations for stable types 203 invalid-atomic-ordering deny usage of invalid atomic ordering in atomic operations and memory fences 204 invalid-doc-attributes deny detects invalid `#[doc(...)]` attributes 205 invalid-from-utf8-unchecked deny using a non UTF-8 literal in `std::str::from_utf8_unchecked` 206 invalid-reference-casting deny casts of `&T` to `&mut T` without interior mutability 207 invalid-type-param-default deny type parameter default erroneously allowed in invalid location 208 let-underscore-lock deny non-binding let on a synchronization lock 209 long-running-const-eval deny detects long const eval operations 210 macro-expanded-macro-exports-accessed-by-absolute-paths deny macro-expanded `macro_export` macros from the current crate cannot be referred to by absolute paths 211 missing-fragment-specifier deny detects missing fragment specifiers in unused `macro_rules!` patterns 212 mutable-transmutes deny transmuting &T to &mut T is undefined behavior, even if the reference is unused 213 named-asm-labels deny named labels in inline assembly 214 no-mangle-const-items deny const items will not have their symbols exported 215 order-dependent-trait-objects deny trait-object types were treated as different depending on marker-trait order 216 overflowing-literals deny literal out of range for its type 217 patterns-in-fns-without-body deny patterns in functions without body were erroneously allowed 218 proc-macro-derive-resolution-fallback deny detects proc macro derives using inaccessible names from parent modules 219 pub-use-of-private-extern-crate deny detect public re-exports of private extern crates 220 soft-unstable deny a feature gate that doesn't break dependent crates 221 test-unstable-lint deny this unstable lint is only for testing 222 text-direction-codepoint-in-comment deny invisible directionality-changing codepoints in comment 223 text-direction-codepoint-in-literal deny detect special Unicode codepoints that affect the visual representation of text on screen, changing the direction in which text flows 224 unconditional-panic deny operation will cause a panic at runtime 225 undropped-manually-drops deny calls to `std::mem::drop` with `std::mem::ManuallyDrop` instead of it's inner value 226 unknown-crate-types deny unknown crate type found in `#[crate_type]` directive 227 useless-deprecated deny detects deprecation attributes with no effect 228 wasm-c-abi deny detects dependencies that are incompatible with the Wasm C ABI 229 230 231 Lint groups provided by rustc: 232 233 name sub-lints 234 ---- --------- 235 warnings all lints that are set to issue warnings 236 deprecated-safe deprecated-safe-2024 237 future-incompatible deref-into-dyn-supertrait, ambiguous-associated-items, ambiguous-glob-imports, cenum-impl-drop-cast, coherence-leak-check, conflicting-repr-hints, const-evaluatable-unchecked, dependency-on-unit-never-type-fallback, elided-lifetimes-in-associated-constant, forbidden-lint-groups, ill-formed-attribute-input, invalid-type-param-default, late-bound-lifetime-arguments, legacy-derive-helpers, macro-expanded-macro-exports-accessed-by-absolute-paths, missing-fragment-specifier, never-type-fallback-flowing-into-unsafe, order-dependent-trait-objects, out-of-scope-macro-calls, patterns-in-fns-without-body, proc-macro-derive-resolution-fallback, ptr-cast-add-auto-to-object, pub-use-of-private-extern-crate, repr-transparent-external-private-fields, self-constructor-from-outer-item, semicolon-in-expressions-from-macros, soft-unstable, uncovered-param-in-projection, uninhabited-static, unstable-name-collisions, unstable-syntax-pre-expansion, unsupported-calling-conventions, unsupported-fn-ptr-calling-conventions, wasm-c-abi 238 keyword-idents keyword-idents-2018, keyword-idents-2024 239 let-underscore let-underscore-drop, let-underscore-lock 240 nonstandard-style non-camel-case-types, non-snake-case, non-upper-case-globals 241 refining-impl-trait refining-impl-trait-reachable, refining-impl-trait-internal 242 rust-2018-compatibility keyword-idents-2018, anonymous-parameters, absolute-paths-not-starting-with-crate, tyvar-behind-raw-pointer 243 rust-2018-idioms bare-trait-objects, unused-extern-crates, ellipsis-inclusive-range-patterns, elided-lifetimes-in-paths, explicit-outlives-requirements 244 rust-2021-compatibility ellipsis-inclusive-range-patterns, bare-trait-objects, rust-2021-incompatible-closure-captures, rust-2021-incompatible-or-patterns, rust-2021-prefixes-incompatible-syntax, rust-2021-prelude-collisions, array-into-iter, non-fmt-panics 245 rust-2024-compatibility keyword-idents-2024, edition-2024-expr-fragment-specifier, deprecated-safe-2024, missing-unsafe-on-extern, rust-2024-guarded-string-incompatible-syntax, rust-2024-prelude-collisions, unsafe-attr-outside-unsafe, unsafe-op-in-unsafe-fn, boxed-slice-into-iter, impl-trait-overcaptures, tail-expr-drop-order, if-let-rescope, static-mut-refs 246 unused unused-imports, unused-variables, unused-assignments, dead-code, unused-mut, unreachable-code, unreachable-patterns, unused-must-use, unused-unsafe, path-statements, unused-attributes, unused-macros, unused-macro-rules, unused-allocation, unused-doc-comments, unused-extern-crates, unused-features, unused-labels, unused-parens, unused-braces, redundant-semicolons, map-unit-fn 247 248 249 Lint tools like Clippy can load additional lints and lint groups.