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/")]
29 #![cfg_attr(test, feature(test))]
30 #![feature(bool_to_option)]
31 #![feature(box_syntax)]
32 #![feature(crate_visibility_modifier)]
33 #![feature(iter_order_by)]
34 #![feature(never_type)]
36 #![feature(or_patterns)]
37 #![recursion_limit = "256"]
40 extern crate rustc_middle;
42 extern crate rustc_session;
52 mod nonstandard_style;
54 mod redundant_semicolon;
60 use rustc_hir::def_id::LocalDefId;
61 use rustc_middle::ty::query::Providers;
62 use rustc_middle::ty::TyCtxt;
63 use rustc_session::lint::builtin::{
64 BARE_TRAIT_OBJECTS, BROKEN_INTRA_DOC_LINKS, ELIDED_LIFETIMES_IN_PATHS,
65 EXPLICIT_OUTLIVES_REQUIREMENTS, INVALID_CODEBLOCK_ATTRIBUTES, MISSING_DOC_CODE_EXAMPLES,
68 use rustc_span::symbol::{Ident, Symbol};
71 use array_into_iter::ArrayIntoIter;
74 use non_ascii_idents::*;
75 use nonstandard_style::*;
76 use redundant_semicolon::*;
80 /// Useful for other parts of the compiler / Clippy.
81 pub use builtin::SoftLints;
82 pub use context::{CheckLintNameResult, EarlyContext, LateContext, LintContext, LintStore};
83 pub use early::check_ast_crate;
84 pub use late::check_crate;
85 pub use passes::{EarlyLintPass, LateLintPass};
86 pub use rustc_session::lint::Level::{self, *};
87 pub use rustc_session::lint::{BufferedEarlyLint, FutureIncompatibleInfo, Lint, LintId};
88 pub use rustc_session::lint::{LintArray, LintPass};
90 pub fn provide(providers: &mut Providers) {
91 levels::provide(providers);
92 *providers = Providers { lint_mod, ..*providers };
95 fn lint_mod(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
96 late::late_lint_mod(tcx, module_def_id, BuiltinCombinedModuleLateLintPass::new());
99 macro_rules! pre_expansion_lint_passes {
100 ($macro:path, $args:tt) => {
101 $macro!($args, [KeywordIdents: KeywordIdents,]);
105 macro_rules! early_lint_passes {
106 ($macro:path, $args:tt) => {
110 UnusedParens: UnusedParens,
111 UnusedBraces: UnusedBraces,
112 UnusedImportBraces: UnusedImportBraces,
113 UnsafeCode: UnsafeCode,
114 AnonymousParameters: AnonymousParameters,
115 EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns::default(),
116 NonCamelCaseTypes: NonCamelCaseTypes,
117 DeprecatedAttr: DeprecatedAttr::new(),
118 WhileTrue: WhileTrue,
119 NonAsciiIdents: NonAsciiIdents,
120 IncompleteFeatures: IncompleteFeatures,
121 RedundantSemicolons: RedundantSemicolons,
122 UnusedDocComment: UnusedDocComment,
128 macro_rules! declare_combined_early_pass {
129 ([$name:ident], $passes:tt) => (
130 early_lint_methods!(declare_combined_early_lint_pass, [pub $name, $passes]);
134 pre_expansion_lint_passes!(declare_combined_early_pass, [BuiltinCombinedPreExpansionLintPass]);
135 early_lint_passes!(declare_combined_early_pass, [BuiltinCombinedEarlyLintPass]);
137 macro_rules! late_lint_passes {
138 ($macro:path, $args:tt) => {
142 // FIXME: Look into regression when this is used as a module lint
143 // May Depend on constants elsewhere
144 UnusedBrokenConst: UnusedBrokenConst,
145 // Uses attr::is_used which is untracked, can't be an incremental module pass.
146 UnusedAttributes: UnusedAttributes::new(),
147 // Needs to run after UnusedAttributes as it marks all `feature` attributes as used.
148 UnstableFeatures: UnstableFeatures,
149 // Tracks state across modules
150 UnnameableTestItems: UnnameableTestItems::new(),
151 // Tracks attributes of parents
152 MissingDoc: MissingDoc::new(),
153 // Depends on access levels
154 // FIXME: Turn the computation of types which implement Debug into a query
155 // and change this to a module lint pass
156 MissingDebugImplementations: MissingDebugImplementations::default(),
157 ArrayIntoIter: ArrayIntoIter,
158 ClashingExternDeclarations: ClashingExternDeclarations::new(),
164 macro_rules! late_lint_mod_passes {
165 ($macro:path, $args:tt) => {
169 HardwiredLints: HardwiredLints,
170 ImproperCTypesDeclarations: ImproperCTypesDeclarations,
171 ImproperCTypesDefinitions: ImproperCTypesDefinitions,
172 VariantSizeDifferences: VariantSizeDifferences,
173 BoxPointers: BoxPointers,
174 PathStatements: PathStatements,
175 // Depends on referenced function signatures in expressions
176 UnusedResults: UnusedResults,
177 NonUpperCaseGlobals: NonUpperCaseGlobals,
178 NonShorthandFieldPatterns: NonShorthandFieldPatterns,
179 UnusedAllocation: UnusedAllocation,
180 // Depends on types used in type definitions
181 MissingCopyImplementations: MissingCopyImplementations,
182 // Depends on referenced function signatures in expressions
183 MutableTransmutes: MutableTransmutes,
184 TypeAliasBounds: TypeAliasBounds,
185 TrivialConstraints: TrivialConstraints,
186 TypeLimits: TypeLimits::new(),
187 NonSnakeCase: NonSnakeCase,
188 InvalidNoMangleItems: InvalidNoMangleItems,
189 // Depends on access levels
190 UnreachablePub: UnreachablePub,
191 ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
192 InvalidValue: InvalidValue,
198 macro_rules! declare_combined_late_pass {
199 ([$v:vis $name:ident], $passes:tt) => (
200 late_lint_methods!(declare_combined_late_lint_pass, [$v $name, $passes], ['tcx]);
204 // FIXME: Make a separate lint type which do not require typeck tables
205 late_lint_passes!(declare_combined_late_pass, [pub BuiltinCombinedLateLintPass]);
207 late_lint_mod_passes!(declare_combined_late_pass, [BuiltinCombinedModuleLateLintPass]);
209 pub fn new_lint_store(no_interleave_lints: bool, internal_lints: bool) -> LintStore {
210 let mut lint_store = LintStore::new();
212 register_builtins(&mut lint_store, no_interleave_lints);
214 register_internals(&mut lint_store);
220 /// Tell the `LintStore` about all the built-in lints (the ones
221 /// defined in this crate and the ones defined in
222 /// `rustc_session::lint::builtin`).
223 fn register_builtins(store: &mut LintStore, no_interleave_lints: bool) {
224 macro_rules! add_lint_group {
225 ($name:expr, $($lint:ident),*) => (
226 store.register_group(false, $name, None, vec![$(LintId::of($lint)),*]);
230 macro_rules! register_pass {
231 ($method:ident, $ty:ident, $constructor:expr) => {
232 store.register_lints(&$ty::get_lints());
233 store.$method(|| box $constructor);
237 macro_rules! register_passes {
238 ($method:ident, [$($passes:ident: $constructor:expr,)*]) => (
240 register_pass!($method, $passes, $constructor);
245 if no_interleave_lints {
246 pre_expansion_lint_passes!(register_passes, register_pre_expansion_pass);
247 early_lint_passes!(register_passes, register_early_pass);
248 late_lint_passes!(register_passes, register_late_pass);
249 late_lint_mod_passes!(register_passes, register_late_mod_pass);
251 store.register_lints(&BuiltinCombinedPreExpansionLintPass::get_lints());
252 store.register_lints(&BuiltinCombinedEarlyLintPass::get_lints());
253 store.register_lints(&BuiltinCombinedModuleLateLintPass::get_lints());
254 store.register_lints(&BuiltinCombinedLateLintPass::get_lints());
259 NON_CAMEL_CASE_TYPES,
261 NON_UPPER_CASE_GLOBALS
272 UNREACHABLE_PATTERNS,
273 OVERLAPPING_PATTERNS,
281 UNUSED_EXTERN_CRATES,
292 UNUSED_EXTERN_CRATES,
293 ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
294 ELIDED_LIFETIMES_IN_PATHS,
295 EXPLICIT_OUTLIVES_REQUIREMENTS // FIXME(#52665, #47816) not always applicable and not all
296 // macros are ready for this yet.
299 // FIXME macro crates are not up for this yet, too much
300 // breakage is seen if we try to encourage this lint.
301 // MACRO_USE_EXTERN_CRATE
306 BROKEN_INTRA_DOC_LINKS,
307 INVALID_CODEBLOCK_ATTRIBUTES,
308 MISSING_DOC_CODE_EXAMPLES,
312 // Register renamed and removed lints.
313 store.register_renamed("single_use_lifetime", "single_use_lifetimes");
314 store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
315 store.register_renamed("bare_trait_object", "bare_trait_objects");
316 store.register_renamed("unstable_name_collision", "unstable_name_collisions");
317 store.register_renamed("unused_doc_comment", "unused_doc_comments");
318 store.register_renamed("async_idents", "keyword_idents");
319 store.register_renamed("exceeding_bitshifts", "arithmetic_overflow");
320 store.register_renamed("redundant_semicolon", "redundant_semicolons");
321 store.register_renamed("intra_doc_link_resolution_failure", "broken_intra_doc_links");
322 store.register_removed("unknown_features", "replaced by an error");
323 store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
324 store.register_removed("negate_unsigned", "cast a signed value instead");
325 store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
326 // Register lint group aliases.
327 store.register_group_alias("nonstandard_style", "bad_style");
328 // This was renamed to `raw_pointer_derive`, which was then removed,
329 // so it is also considered removed.
330 store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
331 store.register_removed("drop_with_repr_extern", "drop flags have been removed");
332 store.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
333 store.register_removed("deprecated_attr", "use `deprecated` instead");
334 store.register_removed(
335 "transmute_from_fn_item_types",
336 "always cast functions before transmuting them",
338 store.register_removed(
339 "hr_lifetime_in_assoc_type",
340 "converted into hard error, see issue #33685 \
341 <https://github.com/rust-lang/rust/issues/33685> for more information",
343 store.register_removed(
344 "inaccessible_extern_crate",
345 "converted into hard error, see issue #36886 \
346 <https://github.com/rust-lang/rust/issues/36886> for more information",
348 store.register_removed(
349 "super_or_self_in_global_path",
350 "converted into hard error, see issue #36888 \
351 <https://github.com/rust-lang/rust/issues/36888> for more information",
353 store.register_removed(
354 "overlapping_inherent_impls",
355 "converted into hard error, see issue #36889 \
356 <https://github.com/rust-lang/rust/issues/36889> for more information",
358 store.register_removed(
359 "illegal_floating_point_constant_pattern",
360 "converted into hard error, see issue #36890 \
361 <https://github.com/rust-lang/rust/issues/36890> for more information",
363 store.register_removed(
364 "illegal_struct_or_enum_constant_pattern",
365 "converted into hard error, see issue #36891 \
366 <https://github.com/rust-lang/rust/issues/36891> for more information",
368 store.register_removed(
369 "lifetime_underscore",
370 "converted into hard error, see issue #36892 \
371 <https://github.com/rust-lang/rust/issues/36892> for more information",
373 store.register_removed(
374 "extra_requirement_in_impl",
375 "converted into hard error, see issue #37166 \
376 <https://github.com/rust-lang/rust/issues/37166> for more information",
378 store.register_removed(
380 "converted into hard error, see issue #38260 \
381 <https://github.com/rust-lang/rust/issues/38260> for more information",
383 store.register_removed(
385 "converted into hard error, see issue #48950 \
386 <https://github.com/rust-lang/rust/issues/48950> for more information",
388 store.register_removed(
389 "resolve_trait_on_defaulted_unit",
390 "converted into hard error, see issue #48950 \
391 <https://github.com/rust-lang/rust/issues/48950> for more information",
393 store.register_removed(
394 "private_no_mangle_fns",
395 "no longer a warning, `#[no_mangle]` functions always exported",
397 store.register_removed(
398 "private_no_mangle_statics",
399 "no longer a warning, `#[no_mangle]` statics always exported",
401 store.register_removed("bad_repr", "replaced with a generic attribute input check");
402 store.register_removed(
403 "duplicate_matcher_binding_name",
404 "converted into hard error, see issue #57742 \
405 <https://github.com/rust-lang/rust/issues/57742> for more information",
407 store.register_removed(
408 "incoherent_fundamental_impls",
409 "converted into hard error, see issue #46205 \
410 <https://github.com/rust-lang/rust/issues/46205> for more information",
412 store.register_removed(
413 "legacy_constructor_visibility",
414 "converted into hard error, see issue #39207 \
415 <https://github.com/rust-lang/rust/issues/39207> for more information",
417 store.register_removed(
418 "legacy_directory_ownership",
419 "converted into hard error, see issue #37872 \
420 <https://github.com/rust-lang/rust/issues/37872> for more information",
422 store.register_removed(
423 "safe_extern_statics",
424 "converted into hard error, see issue #36247 \
425 <https://github.com/rust-lang/rust/issues/36247> for more information",
427 store.register_removed(
428 "parenthesized_params_in_types_and_modules",
429 "converted into hard error, see issue #42238 \
430 <https://github.com/rust-lang/rust/issues/42238> for more information",
432 store.register_removed(
433 "duplicate_macro_exports",
434 "converted into hard error, see issue #35896 \
435 <https://github.com/rust-lang/rust/issues/35896> for more information",
437 store.register_removed(
439 "converted into hard error, see issue #59014 \
440 <https://github.com/rust-lang/rust/issues/59014> for more information",
442 store.register_removed("plugin_as_library", "plugins have been deprecated and retired");
445 fn register_internals(store: &mut LintStore) {
446 store.register_lints(&DefaultHashTypes::get_lints());
447 store.register_early_pass(|| box DefaultHashTypes::new());
448 store.register_lints(&LintPassImpl::get_lints());
449 store.register_early_pass(|| box LintPassImpl);
450 store.register_lints(&TyTyKind::get_lints());
451 store.register_late_pass(|| box TyTyKind);
452 store.register_group(
457 LintId::of(DEFAULT_HASH_TYPES),
458 LintId::of(USAGE_OF_TY_TYKIND),
459 LintId::of(LINT_PASS_IMPL_WITHOUT_MACRO),
460 LintId::of(TY_PASS_BY_REFERENCE),
461 LintId::of(USAGE_OF_QUALIFIED_TY),