1 //! Lints, aka compiler warnings.
3 //! A 'lint' check is a kind of miscellaneous constraint that a user _might_
4 //! want to enforce, but might reasonably want to permit as well, on a
5 //! module-by-module basis. They contrast with static constraints enforced by
6 //! other phases of the compiler, which are generally required to hold in order
7 //! to compile the program at all.
9 //! Most lints can be written as [LintPass] instances. These run after
10 //! all other analyses. The `LintPass`es built into rustc are defined
11 //! within [rustc_session::lint::builtin],
12 //! which has further comments on how to add such a lint.
13 //! rustc can also load user-defined lint plugins via the plugin mechanism.
15 //! Some of rustc's lints are defined elsewhere in the compiler and work by
16 //! calling `add_lint()` on the overall `Session` object. This works when
17 //! it happens before the main lint pass, which emits the lints stored by
18 //! `add_lint()`. To emit lints after the main lint pass (from codegen, for
19 //! example) requires more effort. See `emit_lint` and `GatherNodeLevels`
22 //! Some code also exists in [rustc_session::lint], [rustc_middle::lint].
26 //! This API is completely unstable and subject to change.
28 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
29 #![cfg_attr(test, feature(test))]
30 #![feature(array_windows)]
31 #![feature(bool_to_option)]
32 #![feature(box_syntax)]
33 #![feature(box_patterns)]
34 #![feature(crate_visibility_modifier)]
35 #![feature(iter_order_by)]
37 #![feature(never_type)]
39 #![feature(control_flow_enum)]
40 #![recursion_limit = "256"]
43 extern crate rustc_middle
;
45 extern crate rustc_session
;
57 mod nonstandard_style
;
60 mod redundant_semicolon
;
67 use rustc_hir
::def_id
::LocalDefId
;
68 use rustc_middle
::ty
::query
::Providers
;
69 use rustc_middle
::ty
::TyCtxt
;
70 use rustc_session
::lint
::builtin
::{
71 BARE_TRAIT_OBJECTS
, ELIDED_LIFETIMES_IN_PATHS
, EXPLICIT_OUTLIVES_REQUIREMENTS
,
73 use rustc_span
::symbol
::{Ident, Symbol}
;
76 use array_into_iter
::ArrayIntoIter
;
80 use non_ascii_idents
::*;
81 use non_fmt_panic
::NonPanicFmt
;
82 use nonstandard_style
::*;
83 use noop_method_call
::*;
84 use redundant_semicolon
::*;
89 /// Useful for other parts of the compiler / Clippy.
90 pub use builtin
::SoftLints
;
91 pub use context
::{CheckLintNameResult, EarlyContext, LateContext, LintContext, LintStore}
;
92 pub use early
::check_ast_crate
;
93 pub use late
::check_crate
;
94 pub use passes
::{EarlyLintPass, LateLintPass}
;
95 pub use rustc_session
::lint
::Level
::{self, *}
;
96 pub use rustc_session
::lint
::{BufferedEarlyLint, FutureIncompatibleInfo, Lint, LintId}
;
97 pub use rustc_session
::lint
::{LintArray, LintPass}
;
99 pub fn provide(providers
: &mut Providers
) {
100 levels
::provide(providers
);
101 *providers
= Providers { lint_mod, ..*providers }
;
104 fn lint_mod(tcx
: TyCtxt
<'_
>, module_def_id
: LocalDefId
) {
105 late
::late_lint_mod(tcx
, module_def_id
, BuiltinCombinedModuleLateLintPass
::new());
108 macro_rules
! pre_expansion_lint_passes
{
109 ($
macro:path
, $args
:tt
) => {
110 $
macro!($args
, [KeywordIdents
: KeywordIdents
,]);
114 macro_rules
! early_lint_passes
{
115 ($
macro:path
, $args
:tt
) => {
119 UnusedParens
: UnusedParens
,
120 UnusedBraces
: UnusedBraces
,
121 UnusedImportBraces
: UnusedImportBraces
,
122 UnsafeCode
: UnsafeCode
,
123 AnonymousParameters
: AnonymousParameters
,
124 EllipsisInclusiveRangePatterns
: EllipsisInclusiveRangePatterns
::default(),
125 NonCamelCaseTypes
: NonCamelCaseTypes
,
126 DeprecatedAttr
: DeprecatedAttr
::new(),
127 WhileTrue
: WhileTrue
,
128 NonAsciiIdents
: NonAsciiIdents
,
129 IncompleteFeatures
: IncompleteFeatures
,
130 RedundantSemicolons
: RedundantSemicolons
,
131 UnusedDocComment
: UnusedDocComment
,
137 macro_rules
! declare_combined_early_pass
{
138 ([$name
:ident
], $passes
:tt
) => (
139 early_lint_methods
!(declare_combined_early_lint_pass
, [pub $name
, $passes
]);
143 pre_expansion_lint_passes
!(declare_combined_early_pass
, [BuiltinCombinedPreExpansionLintPass
]);
144 early_lint_passes
!(declare_combined_early_pass
, [BuiltinCombinedEarlyLintPass
]);
146 macro_rules
! late_lint_passes
{
147 ($
macro:path
, $args
:tt
) => {
151 // FIXME: Look into regression when this is used as a module lint
152 // May Depend on constants elsewhere
153 UnusedBrokenConst
: UnusedBrokenConst
,
154 // Uses attr::is_used which is untracked, can't be an incremental module pass.
155 UnusedAttributes
: UnusedAttributes
::new(),
156 // Needs to run after UnusedAttributes as it marks all `feature` attributes as used.
157 UnstableFeatures
: UnstableFeatures
,
158 // Tracks state across modules
159 UnnameableTestItems
: UnnameableTestItems
::new(),
160 // Tracks attributes of parents
161 MissingDoc
: MissingDoc
::new(),
162 // Depends on access levels
163 // FIXME: Turn the computation of types which implement Debug into a query
164 // and change this to a module lint pass
165 MissingDebugImplementations
: MissingDebugImplementations
::default(),
166 ArrayIntoIter
: ArrayIntoIter
::default(),
167 ClashingExternDeclarations
: ClashingExternDeclarations
::new(),
168 DropTraitConstraints
: DropTraitConstraints
,
169 TemporaryCStringAsPtr
: TemporaryCStringAsPtr
,
170 NonPanicFmt
: NonPanicFmt
,
171 NoopMethodCall
: NoopMethodCall
,
177 macro_rules
! late_lint_mod_passes
{
178 ($
macro:path
, $args
:tt
) => {
182 HardwiredLints
: HardwiredLints
,
183 ImproperCTypesDeclarations
: ImproperCTypesDeclarations
,
184 ImproperCTypesDefinitions
: ImproperCTypesDefinitions
,
185 VariantSizeDifferences
: VariantSizeDifferences
,
186 BoxPointers
: BoxPointers
,
187 PathStatements
: PathStatements
,
188 // Depends on referenced function signatures in expressions
189 UnusedResults
: UnusedResults
,
190 NonUpperCaseGlobals
: NonUpperCaseGlobals
,
191 NonShorthandFieldPatterns
: NonShorthandFieldPatterns
,
192 UnusedAllocation
: UnusedAllocation
,
193 // Depends on types used in type definitions
194 MissingCopyImplementations
: MissingCopyImplementations
,
195 // Depends on referenced function signatures in expressions
196 MutableTransmutes
: MutableTransmutes
,
197 TypeAliasBounds
: TypeAliasBounds
,
198 TrivialConstraints
: TrivialConstraints
,
199 TypeLimits
: TypeLimits
::new(),
200 NonSnakeCase
: NonSnakeCase
,
201 InvalidNoMangleItems
: InvalidNoMangleItems
,
202 // Depends on access levels
203 UnreachablePub
: UnreachablePub
,
204 ExplicitOutlivesRequirements
: ExplicitOutlivesRequirements
,
205 InvalidValue
: InvalidValue
,
206 DerefNullPtr
: DerefNullPtr
,
212 macro_rules
! declare_combined_late_pass
{
213 ([$v
:vis $name
:ident
], $passes
:tt
) => (
214 late_lint_methods
!(declare_combined_late_lint_pass
, [$v $name
, $passes
], ['tcx
]);
218 // FIXME: Make a separate lint type which do not require typeck tables
219 late_lint_passes
!(declare_combined_late_pass
, [pub BuiltinCombinedLateLintPass
]);
221 late_lint_mod_passes
!(declare_combined_late_pass
, [BuiltinCombinedModuleLateLintPass
]);
223 pub fn new_lint_store(no_interleave_lints
: bool
, internal_lints
: bool
) -> LintStore
{
224 let mut lint_store
= LintStore
::new();
226 register_builtins(&mut lint_store
, no_interleave_lints
);
228 register_internals(&mut lint_store
);
234 /// Tell the `LintStore` about all the built-in lints (the ones
235 /// defined in this crate and the ones defined in
236 /// `rustc_session::lint::builtin`).
237 fn register_builtins(store
: &mut LintStore
, no_interleave_lints
: bool
) {
238 macro_rules
! add_lint_group
{
239 ($name
:expr
, $
($lint
:ident
),*) => (
240 store
.register_group(false, $name
, None
, vec
![$
(LintId
::of($lint
)),*]);
244 macro_rules
! register_pass
{
245 ($method
:ident
, $ty
:ident
, $constructor
:expr
) => {
246 store
.register_lints(&$ty
::get_lints());
247 store
.$
method(|| box $constructor
);
251 macro_rules
! register_passes
{
252 ($method
:ident
, [$
($passes
:ident
: $constructor
:expr
,)*]) => (
254 register_pass
!($method
, $passes
, $constructor
);
259 if no_interleave_lints
{
260 pre_expansion_lint_passes
!(register_passes
, register_pre_expansion_pass
);
261 early_lint_passes
!(register_passes
, register_early_pass
);
262 late_lint_passes
!(register_passes
, register_late_pass
);
263 late_lint_mod_passes
!(register_passes
, register_late_mod_pass
);
265 store
.register_lints(&BuiltinCombinedPreExpansionLintPass
::get_lints());
266 store
.register_lints(&BuiltinCombinedEarlyLintPass
::get_lints());
267 store
.register_lints(&BuiltinCombinedModuleLateLintPass
::get_lints());
268 store
.register_lints(&BuiltinCombinedLateLintPass
::get_lints());
273 NON_CAMEL_CASE_TYPES
,
275 NON_UPPER_CASE_GLOBALS
286 UNREACHABLE_PATTERNS
,
294 UNUSED_EXTERN_CRATES
,
305 UNUSED_EXTERN_CRATES
,
306 ELLIPSIS_INCLUSIVE_RANGE_PATTERNS
,
307 ELIDED_LIFETIMES_IN_PATHS
,
308 EXPLICIT_OUTLIVES_REQUIREMENTS
// FIXME(#52665, #47816) not always applicable and not all
309 // macros are ready for this yet.
312 // FIXME macro crates are not up for this yet, too much
313 // breakage is seen if we try to encourage this lint.
314 // MACRO_USE_EXTERN_CRATE
317 // Register renamed and removed lints.
318 store
.register_renamed("single_use_lifetime", "single_use_lifetimes");
319 store
.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
320 store
.register_renamed("bare_trait_object", "bare_trait_objects");
321 store
.register_renamed("unstable_name_collision", "unstable_name_collisions");
322 store
.register_renamed("unused_doc_comment", "unused_doc_comments");
323 store
.register_renamed("async_idents", "keyword_idents");
324 store
.register_renamed("exceeding_bitshifts", "arithmetic_overflow");
325 store
.register_renamed("redundant_semicolon", "redundant_semicolons");
326 store
.register_renamed("overlapping_patterns", "overlapping_range_endpoints");
327 store
.register_renamed("safe_packed_borrows", "unaligned_references");
328 store
.register_renamed("disjoint_capture_migration", "rust_2021_incompatible_closure_captures");
329 store
.register_renamed("or_patterns_back_compat", "rust_2021_incompatible_or_patterns");
330 store
.register_renamed("non_fmt_panic", "non_fmt_panics");
332 // These were moved to tool lints, but rustc still sees them when compiling normally, before
333 // tool lints are registered, so `check_tool_name_for_backwards_compat` doesn't work. Use
334 // `register_removed` explicitly.
335 const RUSTDOC_LINTS
: &[&str] = &[
336 "broken_intra_doc_links",
337 "private_intra_doc_links",
338 "missing_crate_level_docs",
339 "missing_doc_code_examples",
341 "invalid_codeblock_attributes",
345 for rustdoc_lint
in RUSTDOC_LINTS
{
346 store
.register_ignored(rustdoc_lint
);
348 store
.register_removed(
349 "intra_doc_link_resolution_failure",
350 "use `rustdoc::broken_intra_doc_links` instead",
352 store
.register_removed("rustdoc", "use `rustdoc::all` instead");
354 store
.register_removed("unknown_features", "replaced by an error");
355 store
.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
356 store
.register_removed("negate_unsigned", "cast a signed value instead");
357 store
.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
358 // Register lint group aliases.
359 store
.register_group_alias("nonstandard_style", "bad_style");
360 // This was renamed to `raw_pointer_derive`, which was then removed,
361 // so it is also considered removed.
362 store
.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
363 store
.register_removed("drop_with_repr_extern", "drop flags have been removed");
364 store
.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
365 store
.register_removed("deprecated_attr", "use `deprecated` instead");
366 store
.register_removed(
367 "transmute_from_fn_item_types",
368 "always cast functions before transmuting them",
370 store
.register_removed(
371 "hr_lifetime_in_assoc_type",
372 "converted into hard error, see issue #33685 \
373 <https://github.com/rust-lang/rust/issues/33685> for more information",
375 store
.register_removed(
376 "inaccessible_extern_crate",
377 "converted into hard error, see issue #36886 \
378 <https://github.com/rust-lang/rust/issues/36886> for more information",
380 store
.register_removed(
381 "super_or_self_in_global_path",
382 "converted into hard error, see issue #36888 \
383 <https://github.com/rust-lang/rust/issues/36888> for more information",
385 store
.register_removed(
386 "overlapping_inherent_impls",
387 "converted into hard error, see issue #36889 \
388 <https://github.com/rust-lang/rust/issues/36889> for more information",
390 store
.register_removed(
391 "illegal_floating_point_constant_pattern",
392 "converted into hard error, see issue #36890 \
393 <https://github.com/rust-lang/rust/issues/36890> for more information",
395 store
.register_removed(
396 "illegal_struct_or_enum_constant_pattern",
397 "converted into hard error, see issue #36891 \
398 <https://github.com/rust-lang/rust/issues/36891> for more information",
400 store
.register_removed(
401 "lifetime_underscore",
402 "converted into hard error, see issue #36892 \
403 <https://github.com/rust-lang/rust/issues/36892> for more information",
405 store
.register_removed(
406 "extra_requirement_in_impl",
407 "converted into hard error, see issue #37166 \
408 <https://github.com/rust-lang/rust/issues/37166> for more information",
410 store
.register_removed(
412 "converted into hard error, see issue #38260 \
413 <https://github.com/rust-lang/rust/issues/38260> for more information",
415 store
.register_removed(
417 "converted into hard error, see issue #48950 \
418 <https://github.com/rust-lang/rust/issues/48950> for more information",
420 store
.register_removed(
421 "resolve_trait_on_defaulted_unit",
422 "converted into hard error, see issue #48950 \
423 <https://github.com/rust-lang/rust/issues/48950> for more information",
425 store
.register_removed(
426 "private_no_mangle_fns",
427 "no longer a warning, `#[no_mangle]` functions always exported",
429 store
.register_removed(
430 "private_no_mangle_statics",
431 "no longer a warning, `#[no_mangle]` statics always exported",
433 store
.register_removed("bad_repr", "replaced with a generic attribute input check");
434 store
.register_removed(
435 "duplicate_matcher_binding_name",
436 "converted into hard error, see issue #57742 \
437 <https://github.com/rust-lang/rust/issues/57742> for more information",
439 store
.register_removed(
440 "incoherent_fundamental_impls",
441 "converted into hard error, see issue #46205 \
442 <https://github.com/rust-lang/rust/issues/46205> for more information",
444 store
.register_removed(
445 "legacy_constructor_visibility",
446 "converted into hard error, see issue #39207 \
447 <https://github.com/rust-lang/rust/issues/39207> for more information",
449 store
.register_removed(
450 "legacy_directory_ownership",
451 "converted into hard error, see issue #37872 \
452 <https://github.com/rust-lang/rust/issues/37872> for more information",
454 store
.register_removed(
455 "safe_extern_statics",
456 "converted into hard error, see issue #36247 \
457 <https://github.com/rust-lang/rust/issues/36247> for more information",
459 store
.register_removed(
460 "parenthesized_params_in_types_and_modules",
461 "converted into hard error, see issue #42238 \
462 <https://github.com/rust-lang/rust/issues/42238> for more information",
464 store
.register_removed(
465 "duplicate_macro_exports",
466 "converted into hard error, see issue #35896 \
467 <https://github.com/rust-lang/rust/issues/35896> for more information",
469 store
.register_removed(
471 "converted into hard error, see issue #59014 \
472 <https://github.com/rust-lang/rust/issues/59014> for more information",
474 store
.register_removed("plugin_as_library", "plugins have been deprecated and retired");
477 fn register_internals(store
: &mut LintStore
) {
478 store
.register_lints(&LintPassImpl
::get_lints());
479 store
.register_early_pass(|| box LintPassImpl
);
480 store
.register_lints(&DefaultHashTypes
::get_lints());
481 store
.register_late_pass(|| box DefaultHashTypes
);
482 store
.register_lints(&ExistingDocKeyword
::get_lints());
483 store
.register_late_pass(|| box ExistingDocKeyword
);
484 store
.register_lints(&TyTyKind
::get_lints());
485 store
.register_late_pass(|| box TyTyKind
);
486 store
.register_group(
491 LintId
::of(DEFAULT_HASH_TYPES
),
492 LintId
::of(USAGE_OF_TY_TYKIND
),
493 LintId
::of(LINT_PASS_IMPL_WITHOUT_MACRO
),
494 LintId
::of(TY_PASS_BY_REFERENCE
),
495 LintId
::of(USAGE_OF_QUALIFIED_TY
),
496 LintId
::of(EXISTING_DOC_KEYWORD
),