1.73.0.txt (27111B)
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 box-pointers allow use of owned (Box type) heap memory 15 deprecated-in-future allow detects use of items that will be deprecated in a future version 16 elided-lifetimes-in-paths allow hidden lifetime parameters in types are deprecated 17 explicit-outlives-requirements allow outlives requirements can be inferred 18 ffi-unwind-calls allow call to foreign functions or function pointers with FFI-unwind ABI 19 fuzzy-provenance-casts allow a fuzzy integer to pointer cast is used 20 keyword-idents allow detects edition keywords being used as an identifier 21 let-underscore-drop allow non-binding let on a type that implements `Drop` 22 lossy-provenance-casts allow a lossy pointer to integer cast is used 23 macro-use-extern-crate allow the `#[macro_use]` attribute is now deprecated in favor of using macros via the module system 24 meta-variable-misuse allow possible meta-variable misuse at macro definition 25 missing-abi allow No declared ABI for extern declaration 26 missing-copy-implementations allow detects potentially-forgotten implementations of `Copy` 27 missing-debug-implementations allow detects missing implementations of Debug 28 missing-docs allow detects missing documentation for public members 29 multiple-supertrait-upcastable allow detect when an object-safe trait has multiple supertraits 30 must-not-suspend allow use of a `#[must_not_suspend]` value across a yield point 31 non-ascii-idents allow detects non-ASCII identifiers 32 non-exhaustive-omitted-patterns allow detect when patterns of types marked `non_exhaustive` are missed 33 pointer-structural-match allow pointers are not structural-match 34 private-bounds allow private type in secondary interface of an item 35 private-interfaces allow private type in primary interface of an item 36 rust-2021-incompatible-closure-captures allow detects closures affected by Rust 2021 changes 37 rust-2021-incompatible-or-patterns allow detects usage of old versions of or-patterns 38 rust-2021-prefixes-incompatible-syntax allow identifiers that will be parsed as a prefix in Rust 2021 39 rust-2021-prelude-collisions allow detects the usage of trait methods which are ambiguous with traits added to the prelude in future editions 40 single-use-lifetimes allow detects lifetime parameters that are only used once 41 trivial-casts allow detects trivial casts which could be removed 42 trivial-numeric-casts allow detects trivial casts of numeric types which could be removed 43 unnameable-types allow effective visibility of a type is larger than the area in which it can be named 44 unreachable-pub allow `pub` items not reachable from crate root 45 unsafe-code allow usage of `unsafe` code and other potentially unsound constructs 46 unsafe-op-in-unsafe-fn allow unsafe operations in unsafe functions without an explicit unsafe block are deprecated 47 unstable-features allow enabling unstable features (deprecated. do not use) 48 unused-crate-dependencies allow crate dependencies that are never used 49 unused-extern-crates allow extern crates that are never used 50 unused-import-braces allow unnecessary braces around an imported item 51 unused-lifetimes allow detects lifetime parameters that are never used 52 unused-macro-rules allow detects macro rules that were not used 53 unused-qualifications allow detects unnecessarily qualified names 54 unused-results allow unused result of an expression in a statement 55 unused-tuple-struct-fields allow detects tuple struct fields that are never read 56 variant-size-differences allow detects enums with widely varying variant sizes 57 ambiguous-glob-imports warn detects certain glob imports that require reporting an ambiguity error 58 ambiguous-glob-reexports warn ambiguous glob re-exports 59 anonymous-parameters warn detects anonymous parameters 60 array-into-iter warn detects calling `into_iter` on arrays in Rust 2015 and 2018 61 asm-sub-register warn using only a subset of a register for inline asm inputs 62 bad-asm-style warn incorrect use of inline assembly 63 bare-trait-objects warn suggest using `dyn Trait` for trait objects 64 break-with-label-and-loop warn `break` expression with label and unlabeled loop as value expression 65 byte-slice-in-packed-struct-with-derive warn `[u8]` or `str` used in a packed struct with `derive` 66 clashing-extern-declarations warn detects when an extern fn has been declared with the same name but different types 67 coherence-leak-check warn distinct impls distinguished only by the leak-check code 68 coinductive-overlap-in-coherence warn impls that are not considered to overlap may be considered to overlap in the future 69 confusable-idents warn detects visually confusable pairs between identifiers 70 const-evaluatable-unchecked warn detects a generic constant is used in a type without a emitting a warning 71 const-item-mutation warn detects attempts to mutate a `const` item 72 dead-code warn detect unused, unexported items 73 deprecated warn detects use of deprecated items 74 deprecated-where-clause-location warn deprecated where clause location 75 deref-into-dyn-supertrait warn `Deref` implementation usage with a supertrait trait object for output might be shadowed in the future 76 deref-nullptr warn detects when an null pointer is dereferenced 77 dropping-copy-types warn calls to `std::mem::drop` with a value that implements Copy 78 dropping-references warn calls to `std::mem::drop` with a reference instead of an owned value 79 drop-bounds warn bounds of the form `T: Drop` are most likely incorrect 80 duplicate-macro-attributes warn duplicated attribute 81 dyn-drop warn trait objects of the form `dyn Drop` are useless 82 ellipsis-inclusive-range-patterns warn `...` range patterns are deprecated 83 exported-private-dependencies warn public interface leaks type from a private dependency 84 forbidden-lint-groups warn applying forbid to lint-groups 85 forgetting-copy-types warn calls to `std::mem::forget` with a value that implements Copy 86 forgetting-references warn calls to `std::mem::forget` with a reference instead of an owned value 87 for-loops-over-fallibles warn for-looping over an `Option` or a `Result`, which is more clearly expressed as an `if let` 88 function-item-references warn suggest casting to a function pointer when attempting to take references to function items 89 hidden-glob-reexports warn name introduced by a private item shadows a name introduced by a public glob re-export 90 illegal-floating-point-literal-pattern warn floating-point literals cannot be used in patterns 91 improper-ctypes warn proper use of libc types in foreign modules 92 improper-ctypes-definitions warn proper use of libc types in foreign item definitions 93 incomplete-features warn incomplete features that may function improperly in some or all cases 94 indirect-structural-match warn constant used in pattern contains value of non-structural-match type in a field or a variant 95 inline-no-sanitize warn detects incompatible use of `#[inline(always)]` and `#[no_sanitize(...)]` 96 internal-features warn internal features are not supposed to be used 97 invalid-doc-attributes warn detects invalid `#[doc(...)]` attributes 98 invalid-from-utf8 warn using a non UTF-8 literal in `std::str::from_utf8` 99 invalid-macro-export-arguments warn "invalid_parameter" isn't a valid argument for `#[macro_export]` 100 invalid-nan-comparisons warn detects invalid floating point NaN comparisons 101 invalid-value warn an invalid value is being created (such as a null reference) 102 irrefutable-let-patterns warn detects irrefutable patterns in `if let` and `while let` statements 103 large-assignments warn detects large moves or copies 104 late-bound-lifetime-arguments warn detects generic lifetime arguments in path segments with late bound lifetime parameters 105 legacy-derive-helpers warn detects derive helper attributes that are used before they are introduced 106 map-unit-fn warn `Iterator::map` call that discard the iterator's values 107 mixed-script-confusables warn detects Unicode scripts whose mixed script confusables codepoints are solely used 108 named-arguments-used-positionally warn named arguments in format used positionally 109 nontrivial-structural-match warn constant used in pattern of non-structural-match type and the constant's initializer expression contains values of non-structural-match types 110 non-camel-case-types warn types, variants, traits and type parameters should have camel case names 111 non-fmt-panics warn detect single-argument panic!() invocations in which the argument is not a format string 112 non-shorthand-field-patterns warn using `Struct { x: x }` instead of `Struct { x }` in a pattern 113 non-snake-case warn variables, methods, functions, lifetime parameters and modules should have snake case names 114 non-upper-case-globals warn static constants should have uppercase identifiers 115 noop-method-call warn detects the use of well-known noop methods 116 no-mangle-generic-items warn generic items must be mangled 117 opaque-hidden-inferred-bound warn detects the use of nested `impl Trait` types in associated type bounds that are not general enough 118 overlapping-range-endpoints warn detects range patterns with overlapping endpoints 119 path-statements warn path statements with no effect 120 private-in-public warn detect private items in public interfaces not caught by the old implementation 121 redundant-semicolons warn detects unnecessary trailing semicolons 122 renamed-and-removed-lints warn lints that have been renamed or removed 123 repr-transparent-external-private-fields warn transparent type contains an external ZST that is marked #[non_exhaustive] or contains private fields 124 semicolon-in-expressions-from-macros warn trailing semicolon in macro body used as expression 125 special-module-name warn module declarations for files with a special meaning 126 stable-features warn stable features found in `#[feature]` directive 127 suspicious-auto-trait-impls warn the rules governing auto traits have recently changed resulting in potential breakage 128 suspicious-double-ref-op warn suspicious call of trait method on `&&T` 129 temporary-cstring-as-ptr warn detects getting the inner pointer of a temporary `CString` 130 trivial-bounds warn these bounds don't depend on an type parameters 131 type-alias-bounds warn bounds in type aliases are not enforced 132 tyvar-behind-raw-pointer warn raw pointer to an inference variable 133 uncommon-codepoints warn detects uncommon Unicode codepoints in identifiers 134 unconditional-recursion warn functions that cannot return without calling themselves 135 undefined-naked-function-abi warn undefined naked function ABI 136 unexpected-cfgs warn detects unexpected names and values in `#[cfg]` conditions 137 unfulfilled-lint-expectations warn unfulfilled lint expectation 138 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 139 uninhabited-static warn uninhabited static 140 unknown-diagnostic-attributes warn unrecognized diagnostic attribute 141 unknown-lints warn unrecognized lint attribute 142 unnameable-test-items warn detects an item that cannot be named being marked as `#[test_case]` 143 unreachable-code warn detects unreachable code paths 144 unreachable-patterns warn detects unreachable patterns 145 unstable-name-collisions warn detects name collision with an existing but unstable method 146 unstable-syntax-pre-expansion warn unstable syntax can change at any point in the future, causing a hard error! 147 unsupported-calling-conventions warn use of unsupported calling convention 148 unused-allocation warn detects unnecessary allocations that can be eliminated 149 unused-assignments warn detect assignments that will never be read 150 unused-associated-type-bounds warn detects unused `Foo = Bar` bounds in `dyn Trait<Foo = Bar>` 151 unused-attributes warn detects attributes that were not used by the compiler 152 unused-braces warn unnecessary braces around an expression 153 unused-comparisons warn comparisons made useless by limits of the types involved 154 unused-doc-comments warn detects doc comments that aren't used by rustdoc 155 unused-features warn unused features found in crate-level `#[feature]` directives 156 unused-imports warn imports that are never used 157 unused-labels warn detects labels that are never used 158 unused-macros warn detects macros that were not used 159 unused-must-use warn unused result of a type flagged as `#[must_use]` 160 unused-mut warn detect mut variables which don't need to be mutable 161 unused-parens warn `if`, `match`, `while` and `return` do not need parentheses 162 unused-unsafe warn unnecessary use of an `unsafe` block 163 unused-variables warn detect variables which are not used in any way 164 useless-ptr-null-checks warn useless checking of non-null-typed pointer 165 warnings warn mass-change the level for lints which produce warnings 166 where-clauses-object-safety warn checks the object safety of where clauses 167 while-true warn suggest using `loop { }` instead of `while true { }` 168 ambiguous-associated-items deny ambiguous associated items 169 arithmetic-overflow deny arithmetic operation overflows 170 bindings-with-variant-name deny detects pattern bindings with the same name as one of the matched variants 171 cenum-impl-drop-cast deny a C-like enum implementing Drop is cast 172 conflicting-repr-hints deny conflicts between `#[repr(..)]` hints that were previously accepted and used in practice 173 deprecated-cfg-attr-crate-type-name deny detects usage of `#![cfg_attr(..., crate_type/crate_name = "...")]` 174 enum-intrinsics-non-enums deny detects calls to `core::mem::discriminant` and `core::mem::variant_count` with non-enum types 175 ill-formed-attribute-input deny ill-formed attribute inputs that were previously accepted and used in practice 176 implied-bounds-entailment deny impl method assumes more implied bounds than its corresponding trait method 177 incomplete-include deny trailing content in included file 178 ineffective-unstable-trait-impl deny detects `#[unstable]` on stable trait implementations for stable types 179 invalid-alignment deny raw pointers must be aligned before dereferencing 180 invalid-atomic-ordering deny usage of invalid atomic ordering in atomic operations and memory fences 181 invalid-from-utf8-unchecked deny using a non UTF-8 literal in `std::str::from_utf8_unchecked` 182 invalid-reference-casting deny casts of `&T` to `&mut T` without interior mutability 183 invalid-type-param-default deny type parameter default erroneously allowed in invalid location 184 let-underscore-lock deny non-binding let on a synchronization lock 185 long-running-const-eval deny detects long const eval operations 186 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 187 missing-fragment-specifier deny detects missing fragment specifiers in unused `macro_rules!` patterns 188 mutable-transmutes deny transmuting &T to &mut T is undefined behavior, even if the reference is unused 189 named-asm-labels deny named labels in inline assembly 190 no-mangle-const-items deny const items will not have their symbols exported 191 order-dependent-trait-objects deny trait-object types were treated as different depending on marker-trait order 192 overflowing-literals deny literal out of range for its type 193 patterns-in-fns-without-body deny patterns in functions without body were erroneously allowed 194 proc-macro-back-compat deny detects usage of old versions of certain proc-macro crates 195 proc-macro-derive-resolution-fallback deny detects proc macro derives using inaccessible names from parent modules 196 pub-use-of-private-extern-crate deny detect public re-exports of private extern crates 197 soft-unstable deny a feature gate that doesn't break dependent crates 198 test-unstable-lint deny this unstable lint is only for testing 199 text-direction-codepoint-in-comment deny invisible directionality-changing codepoints in comment 200 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 201 unconditional-panic deny operation will cause a panic at runtime 202 undropped-manually-drops deny calls to `std::mem::drop` with `std::mem::ManuallyDrop` instead of it's inner value 203 unknown-crate-types deny unknown crate type found in `#[crate_type]` directive 204 useless-deprecated deny detects deprecation attributes with no effect 205 206 207 Lint groups provided by rustc: 208 209 name sub-lints 210 ---- --------- 211 warnings all lints that are set to issue warnings 212 future-incompatible deref-into-dyn-supertrait, ambiguous-associated-items, ambiguous-glob-imports, byte-slice-in-packed-struct-with-derive, cenum-impl-drop-cast, coherence-leak-check, coinductive-overlap-in-coherence, conflicting-repr-hints, const-evaluatable-unchecked, deprecated-cfg-attr-crate-type-name, forbidden-lint-groups, ill-formed-attribute-input, illegal-floating-point-literal-pattern, implied-bounds-entailment, indirect-structural-match, invalid-alignment, invalid-doc-attributes, invalid-type-param-default, late-bound-lifetime-arguments, legacy-derive-helpers, macro-expanded-macro-exports-accessed-by-absolute-paths, missing-fragment-specifier, nontrivial-structural-match, order-dependent-trait-objects, patterns-in-fns-without-body, pointer-structural-match, private-in-public, proc-macro-back-compat, proc-macro-derive-resolution-fallback, pub-use-of-private-extern-crate, repr-transparent-external-private-fields, semicolon-in-expressions-from-macros, soft-unstable, suspicious-auto-trait-impls, uninhabited-static, unstable-name-collisions, unstable-syntax-pre-expansion, unsupported-calling-conventions, where-clauses-object-safety 213 let-underscore let-underscore-drop, let-underscore-lock 214 nonstandard-style non-camel-case-types, non-snake-case, non-upper-case-globals 215 rust-2018-compatibility keyword-idents, anonymous-parameters, absolute-paths-not-starting-with-crate, tyvar-behind-raw-pointer 216 rust-2018-idioms bare-trait-objects, unused-extern-crates, ellipsis-inclusive-range-patterns, elided-lifetimes-in-paths, explicit-outlives-requirements 217 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 218 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 219 220 221 Lint tools like Clippy can provide additional lints and lint groups.