1.66.0.txt (23187B)
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 must-not-suspend allow use of a `#[must_not_suspend]` value across a yield point 30 non-ascii-idents allow detects non-ASCII identifiers 31 non-exhaustive-omitted-patterns allow detect when patterns of types marked `non_exhaustive` are missed 32 noop-method-call allow detects the use of well-known noop methods 33 pointer-structural-match allow pointers are not structural-match 34 rust-2021-incompatible-closure-captures allow detects closures affected by Rust 2021 changes 35 rust-2021-incompatible-or-patterns allow detects usage of old versions of or-patterns 36 rust-2021-prefixes-incompatible-syntax allow identifiers that will be parsed as a prefix in Rust 2021 37 rust-2021-prelude-collisions allow detects the usage of trait methods which are ambiguous with traits added to the prelude in future editions 38 single-use-lifetimes allow detects lifetime parameters that are only used once 39 trivial-casts allow detects trivial casts which could be removed 40 trivial-numeric-casts allow detects trivial casts of numeric types which could be removed 41 unreachable-pub allow `pub` items not reachable from crate root 42 unsafe-code allow usage of `unsafe` code 43 unsafe-op-in-unsafe-fn allow unsafe operations in unsafe functions without an explicit unsafe block are deprecated 44 unstable-features allow enabling unstable features (deprecated. do not use) 45 unused-crate-dependencies allow crate dependencies that are never used 46 unused-extern-crates allow extern crates that are never used 47 unused-import-braces allow unnecessary braces around an imported item 48 unused-lifetimes allow detects lifetime parameters that are never used 49 unused-macro-rules allow detects macro rules that were not used 50 unused-qualifications allow detects unnecessarily qualified names 51 unused-results allow unused result of an expression in a statement 52 unused-tuple-struct-fields allow detects tuple struct fields that are never read 53 variant-size-differences allow detects enums with widely varying variant sizes 54 anonymous-parameters warn detects anonymous parameters 55 array-into-iter warn detects calling `into_iter` on arrays in Rust 2015 and 2018 56 asm-sub-register warn using only a subset of a register for inline asm inputs 57 bad-asm-style warn incorrect use of inline assembly 58 bare-trait-objects warn suggest using `dyn Trait` for trait objects 59 bindings-with-variant-name warn detects pattern bindings with the same name as one of the matched variants 60 break-with-label-and-loop warn `break` expression with label and unlabeled loop as value expression 61 clashing-extern-declarations warn detects when an extern fn has been declared with the same name but different types 62 coherence-leak-check warn distinct impls distinguished only by the leak-check code 63 confusable-idents warn detects visually confusable pairs between identifiers 64 const-evaluatable-unchecked warn detects a generic constant is used in a type without a emitting a warning 65 const-item-mutation warn detects attempts to mutate a `const` item 66 dead-code warn detect unused, unexported items 67 deprecated warn detects use of deprecated items 68 deprecated-where-clause-location warn deprecated where clause location 69 deref-into-dyn-supertrait warn `Deref` implementation usage with a supertrait trait object for output might be shadowed in the future 70 deref-nullptr warn detects when an null pointer is dereferenced 71 drop-bounds warn bounds of the form `T: Drop` are most likely incorrect 72 duplicate-macro-attributes warn duplicated attribute 73 dyn-drop warn trait objects of the form `dyn Drop` are useless 74 ellipsis-inclusive-range-patterns warn `...` range patterns are deprecated 75 exported-private-dependencies warn public interface leaks type from a private dependency 76 forbidden-lint-groups warn applying forbid to lint-groups 77 for-loops-over-fallibles warn for-looping over an `Option` or a `Result`, which is more clearly expressed as an `if let` 78 function-item-references warn suggest casting to a function pointer when attempting to take references to function items 79 illegal-floating-point-literal-pattern warn floating-point literals cannot be used in patterns 80 improper-ctypes warn proper use of libc types in foreign modules 81 improper-ctypes-definitions warn proper use of libc types in foreign item definitions 82 incomplete-features warn incomplete features that may function improperly in some or all cases 83 indirect-structural-match warn constant used in pattern contains value of non-structural-match type in a field or a variant 84 inline-no-sanitize warn detects incompatible use of `#[inline(always)]` and `#[no_sanitize(...)]` 85 invalid-doc-attributes warn detects invalid `#[doc(...)]` attributes 86 invalid-value warn an invalid value is being created (such as a null reference) 87 irrefutable-let-patterns warn detects irrefutable patterns in `if let` and `while let` statements 88 large-assignments warn detects large moves or copies 89 late-bound-lifetime-arguments warn detects generic lifetime arguments in path segments with late bound lifetime parameters 90 legacy-derive-helpers warn detects derive helper attributes that are used before they are introduced 91 mixed-script-confusables warn detects Unicode scripts whose mixed script confusables codepoints are solely used 92 named-arguments-used-positionally warn named arguments in format used positionally 93 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 94 non-camel-case-types warn types, variants, traits and type parameters should have camel case names 95 non-fmt-panics warn detect single-argument panic!() invocations in which the argument is not a format string 96 non-shorthand-field-patterns warn using `Struct { x: x }` instead of `Struct { x }` in a pattern 97 non-snake-case warn variables, methods, functions, lifetime parameters and modules should have snake case names 98 non-upper-case-globals warn static constants should have uppercase identifiers 99 no-mangle-generic-items warn generic items must be mangled 100 opaque-hidden-inferred-bound warn detects the use of nested `impl Trait` types in associated type bounds that are not general enough 101 overlapping-range-endpoints warn detects range patterns with overlapping endpoints 102 path-statements warn path statements with no effect 103 private-in-public warn detect private items in public interfaces not caught by the old implementation 104 redundant-semicolons warn detects unnecessary trailing semicolons 105 renamed-and-removed-lints warn lints that have been renamed or removed 106 repr-transparent-external-private-fields warn transparent type contains an external ZST that is marked #[non_exhaustive] or contains private fields 107 semicolon-in-expressions-from-macros warn trailing semicolon in macro body used as expression 108 special-module-name warn module declarations for files with a special meaning 109 stable-features warn stable features found in `#[feature]` directive 110 suspicious-auto-trait-impls warn the rules governing auto traits will change in the future 111 temporary-cstring-as-ptr warn detects getting the inner pointer of a temporary `CString` 112 trivial-bounds warn these bounds don't depend on an type parameters 113 type-alias-bounds warn bounds in type aliases are not enforced 114 tyvar-behind-raw-pointer warn raw pointer to an inference variable 115 uncommon-codepoints warn detects uncommon Unicode codepoints in identifiers 116 unconditional-recursion warn functions that cannot return without calling themselves 117 unexpected-cfgs warn detects unexpected names and values in `#[cfg]` conditions 118 unfulfilled-lint-expectations warn unfulfilled lint expectation 119 uninhabited-static warn uninhabited static 120 unknown-lints warn unrecognized lint attribute 121 unnameable-test-items warn detects an item that cannot be named being marked as `#[test_case]` 122 unreachable-code warn detects unreachable code paths 123 unreachable-patterns warn detects unreachable patterns 124 unstable-name-collisions warn detects name collision with an existing but unstable method 125 unstable-syntax-pre-expansion warn unstable syntax can change at any point in the future, causing a hard error! 126 unsupported-calling-conventions warn use of unsupported calling convention 127 unused-allocation warn detects unnecessary allocations that can be eliminated 128 unused-assignments warn detect assignments that will never be read 129 unused-attributes warn detects attributes that were not used by the compiler 130 unused-braces warn unnecessary braces around an expression 131 unused-comparisons warn comparisons made useless by limits of the types involved 132 unused-doc-comments warn detects doc comments that aren't used by rustdoc 133 unused-features warn unused features found in crate-level `#[feature]` directives 134 unused-imports warn imports that are never used 135 unused-labels warn detects labels that are never used 136 unused-macros warn detects macros that were not used 137 unused-must-use warn unused result of a type flagged as `#[must_use]` 138 unused-mut warn detect mut variables which don't need to be mutable 139 unused-parens warn `if`, `match`, `while` and `return` do not need parentheses 140 unused-unsafe warn unnecessary use of an `unsafe` block 141 unused-variables warn detect variables which are not used in any way 142 warnings warn mass-change the level for lints which produce warnings 143 where-clauses-object-safety warn checks the object safety of where clauses 144 while-true warn suggest using `loop { }` instead of `while true { }` 145 ambiguous-associated-items deny ambiguous associated items 146 arithmetic-overflow deny arithmetic operation overflows 147 cenum-impl-drop-cast deny a C-like enum implementing Drop is cast 148 conflicting-repr-hints deny conflicts between `#[repr(..)]` hints that were previously accepted and used in practice 149 deprecated-cfg-attr-crate-type-name deny detects usage of `#![cfg_attr(..., crate_type/crate_name = "...")]` 150 enum-intrinsics-non-enums deny detects calls to `core::mem::discriminant` and `core::mem::variant_count` with non-enum types 151 ill-formed-attribute-input deny ill-formed attribute inputs that were previously accepted and used in practice 152 incomplete-include deny trailing content in included file 153 ineffective-unstable-trait-impl deny detects `#[unstable]` on stable trait implementations for stable types 154 invalid-atomic-ordering deny usage of invalid atomic ordering in atomic operations and memory fences 155 invalid-type-param-default deny type parameter default erroneously allowed in invalid location 156 let-underscore-lock deny non-binding let on a synchronization lock 157 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 158 missing-fragment-specifier deny detects missing fragment specifiers in unused `macro_rules!` patterns 159 mutable-transmutes deny transmuting &T to &mut T is undefined behavior, even if the reference is unused 160 named-asm-labels deny named labels in inline assembly 161 no-mangle-const-items deny const items will not have their symbols exported 162 order-dependent-trait-objects deny trait-object types were treated as different depending on marker-trait order 163 overflowing-literals deny literal out of range for its type 164 patterns-in-fns-without-body deny patterns in functions without body were erroneously allowed 165 proc-macro-back-compat deny detects usage of old versions of certain proc-macro crates 166 proc-macro-derive-resolution-fallback deny detects proc macro derives using inaccessible names from parent modules 167 pub-use-of-private-extern-crate deny detect public re-exports of private extern crates 168 soft-unstable deny a feature gate that doesn't break dependent crates 169 test-unstable-lint deny this unstable lint is only for testing 170 text-direction-codepoint-in-comment deny invisible directionality-changing codepoints in comment 171 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 172 unaligned-references deny detects unaligned references to fields of packed structs 173 unconditional-panic deny operation will cause a panic at runtime 174 unknown-crate-types deny unknown crate type found in `#[crate_type]` directive 175 useless-deprecated deny detects deprecation attributes with no effect 176 177 178 Lint groups provided by rustc: 179 180 name sub-lints 181 ---- --------- 182 warnings all lints that are set to issue warnings 183 future-incompatible forbidden-lint-groups, illegal-floating-point-literal-pattern, private-in-public, pub-use-of-private-extern-crate, invalid-type-param-default, unaligned-references, patterns-in-fns-without-body, missing-fragment-specifier, late-bound-lifetime-arguments, order-dependent-trait-objects, coherence-leak-check, unstable-name-collisions, where-clauses-object-safety, proc-macro-derive-resolution-fallback, macro-expanded-macro-exports-accessed-by-absolute-paths, ill-formed-attribute-input, conflicting-repr-hints, ambiguous-associated-items, indirect-structural-match, pointer-structural-match, nontrivial-structural-match, soft-unstable, unstable-syntax-pre-expansion, cenum-impl-drop-cast, const-evaluatable-unchecked, uninhabited-static, invalid-doc-attributes, semicolon-in-expressions-from-macros, legacy-derive-helpers, proc-macro-back-compat, unsupported-calling-conventions, deref-into-dyn-supertrait, deprecated-cfg-attr-crate-type-name, suspicious-auto-trait-impls, repr-transparent-external-private-fields 184 let-underscore let-underscore-drop, let-underscore-lock 185 nonstandard-style non-camel-case-types, non-snake-case, non-upper-case-globals 186 rust-2018-compatibility keyword-idents, anonymous-parameters, tyvar-behind-raw-pointer, absolute-paths-not-starting-with-crate 187 rust-2018-idioms bare-trait-objects, unused-extern-crates, ellipsis-inclusive-range-patterns, elided-lifetimes-in-paths, explicit-outlives-requirements 188 rust-2021-compatibility ellipsis-inclusive-range-patterns, bare-trait-objects, rust-2021-incompatible-closure-captures, rust-2021-incompatible-or-patterns, rust-2021-prelude-collisions, rust-2021-prefixes-incompatible-syntax, array-into-iter, non-fmt-panics 189 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 190 191 192 Lint tools like Clippy can provide additional lints and lint groups.