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::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(never_type)]
35 #![recursion_limit = "256"]
40 extern crate rustc_session;
50 mod nonstandard_style;
52 mod redundant_semicolon;
56 use rustc::ty::query::Providers;
57 use rustc::ty::TyCtxt;
59 use rustc_hir::def_id::DefId;
60 use rustc_session::lint::builtin::{
61 BARE_TRAIT_OBJECTS, ELIDED_LIFETIMES_IN_PATHS, EXPLICIT_OUTLIVES_REQUIREMENTS,
62 INTRA_DOC_LINK_RESOLUTION_FAILURE, MISSING_DOC_CODE_EXAMPLES, PRIVATE_DOC_TESTS,
67 use array_into_iter::ArrayIntoIter;
70 use non_ascii_idents::*;
71 use nonstandard_style::*;
72 use redundant_semicolon::*;
76 /// Useful for other parts of the compiler / Clippy.
77 pub use builtin::SoftLints;
78 pub use context::{CheckLintNameResult, EarlyContext, LateContext, LintContext, LintStore};
79 pub use early::check_ast_crate;
80 pub use late::check_crate;
81 pub use passes::{EarlyLintPass, LateLintPass};
82 pub use rustc_session::lint::Level::{self, *};
83 pub use rustc_session::lint::{BufferedEarlyLint, FutureIncompatibleInfo, Lint, LintId};
84 pub use rustc_session::lint::{LintArray, LintPass};
86 pub fn provide(providers: &mut Providers<'_>) {
87 levels::provide(providers);
88 *providers = Providers { lint_mod, ..*providers };
91 fn lint_mod(tcx: TyCtxt<'_>, module_def_id: DefId) {
92 late::late_lint_mod(tcx, module_def_id, BuiltinCombinedModuleLateLintPass::new());
95 macro_rules! pre_expansion_lint_passes {
96 ($macro:path, $args:tt) => {
97 $macro!($args, [KeywordIdents: KeywordIdents,]);
101 macro_rules! early_lint_passes {
102 ($macro:path, $args:tt) => {
106 UnusedParens: UnusedParens,
107 UnusedImportBraces: UnusedImportBraces,
108 UnsafeCode: UnsafeCode,
109 AnonymousParameters: AnonymousParameters,
110 EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns::default(),
111 NonCamelCaseTypes: NonCamelCaseTypes,
112 DeprecatedAttr: DeprecatedAttr::new(),
113 WhileTrue: WhileTrue,
114 NonAsciiIdents: NonAsciiIdents,
115 IncompleteFeatures: IncompleteFeatures,
116 RedundantSemicolon: RedundantSemicolon,
117 UnusedDocComment: UnusedDocComment,
123 macro_rules! declare_combined_early_pass {
124 ([$name:ident], $passes:tt) => (
125 early_lint_methods!(declare_combined_early_lint_pass, [pub $name, $passes]);
129 pre_expansion_lint_passes!(declare_combined_early_pass, [BuiltinCombinedPreExpansionLintPass]);
130 early_lint_passes!(declare_combined_early_pass, [BuiltinCombinedEarlyLintPass]);
132 macro_rules! late_lint_passes {
133 ($macro:path, $args:tt) => {
137 // FIXME: Look into regression when this is used as a module lint
138 // May Depend on constants elsewhere
139 UnusedBrokenConst: UnusedBrokenConst,
140 // Uses attr::is_used which is untracked, can't be an incremental module pass.
141 UnusedAttributes: UnusedAttributes::new(),
142 // Needs to run after UnusedAttributes as it marks all `feature` attributes as used.
143 UnstableFeatures: UnstableFeatures,
144 // Tracks state across modules
145 UnnameableTestItems: UnnameableTestItems::new(),
146 // Tracks attributes of parents
147 MissingDoc: MissingDoc::new(),
148 // Depends on access levels
149 // FIXME: Turn the computation of types which implement Debug into a query
150 // and change this to a module lint pass
151 MissingDebugImplementations: MissingDebugImplementations::default(),
152 ArrayIntoIter: ArrayIntoIter,
158 macro_rules! late_lint_mod_passes {
159 ($macro:path, $args:tt) => {
163 HardwiredLints: HardwiredLints,
164 ImproperCTypes: ImproperCTypes,
165 VariantSizeDifferences: VariantSizeDifferences,
166 BoxPointers: BoxPointers,
167 PathStatements: PathStatements,
168 // Depends on referenced function signatures in expressions
169 UnusedResults: UnusedResults,
170 NonUpperCaseGlobals: NonUpperCaseGlobals,
171 NonShorthandFieldPatterns: NonShorthandFieldPatterns,
172 UnusedAllocation: UnusedAllocation,
173 // Depends on types used in type definitions
174 MissingCopyImplementations: MissingCopyImplementations,
175 // Depends on referenced function signatures in expressions
176 MutableTransmutes: MutableTransmutes,
177 TypeAliasBounds: TypeAliasBounds,
178 TrivialConstraints: TrivialConstraints,
179 TypeLimits: TypeLimits::new(),
180 NonSnakeCase: NonSnakeCase,
181 InvalidNoMangleItems: InvalidNoMangleItems,
182 // Depends on access levels
183 UnreachablePub: UnreachablePub,
184 ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
185 InvalidValue: InvalidValue,
191 macro_rules! declare_combined_late_pass {
192 ([$v:vis $name:ident], $passes:tt) => (
193 late_lint_methods!(declare_combined_late_lint_pass, [$v $name, $passes], ['tcx]);
197 // FIXME: Make a separate lint type which do not require typeck tables
198 late_lint_passes!(declare_combined_late_pass, [pub BuiltinCombinedLateLintPass]);
200 late_lint_mod_passes!(declare_combined_late_pass, [BuiltinCombinedModuleLateLintPass]);
202 pub fn new_lint_store(no_interleave_lints: bool, internal_lints: bool) -> LintStore {
203 let mut lint_store = LintStore::new();
205 register_builtins(&mut lint_store, no_interleave_lints);
207 register_internals(&mut lint_store);
213 /// Tell the `LintStore` about all the built-in lints (the ones
214 /// defined in this crate and the ones defined in
215 /// `rustc::lint::builtin`).
216 fn register_builtins(store: &mut LintStore, no_interleave_lints: bool) {
217 macro_rules! add_lint_group {
218 ($name:expr, $($lint:ident),*) => (
219 store.register_group(false, $name, None, vec![$(LintId::of($lint)),*]);
223 macro_rules! register_pass {
224 ($method:ident, $ty:ident, $constructor:expr) => {
225 store.register_lints(&$ty::get_lints());
226 store.$method(|| box $constructor);
230 macro_rules! register_passes {
231 ($method:ident, [$($passes:ident: $constructor:expr,)*]) => (
233 register_pass!($method, $passes, $constructor);
238 if no_interleave_lints {
239 pre_expansion_lint_passes!(register_passes, register_pre_expansion_pass);
240 early_lint_passes!(register_passes, register_early_pass);
241 late_lint_passes!(register_passes, register_late_pass);
242 late_lint_mod_passes!(register_passes, register_late_mod_pass);
244 store.register_lints(&BuiltinCombinedPreExpansionLintPass::get_lints());
245 store.register_lints(&BuiltinCombinedEarlyLintPass::get_lints());
246 store.register_lints(&BuiltinCombinedModuleLateLintPass::get_lints());
247 store.register_lints(&BuiltinCombinedLateLintPass::get_lints());
252 NON_CAMEL_CASE_TYPES,
254 NON_UPPER_CASE_GLOBALS
265 UNREACHABLE_PATTERNS,
266 OVERLAPPING_PATTERNS,
274 UNUSED_EXTERN_CRATES,
283 UNUSED_EXTERN_CRATES,
284 ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
285 ELIDED_LIFETIMES_IN_PATHS,
286 EXPLICIT_OUTLIVES_REQUIREMENTS // FIXME(#52665, #47816) not always applicable and not all
287 // macros are ready for this yet.
290 // FIXME macro crates are not up for this yet, too much
291 // breakage is seen if we try to encourage this lint.
292 // MACRO_USE_EXTERN_CRATE
297 INTRA_DOC_LINK_RESOLUTION_FAILURE,
298 MISSING_DOC_CODE_EXAMPLES,
302 // Register renamed and removed lints.
303 store.register_renamed("single_use_lifetime", "single_use_lifetimes");
304 store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
305 store.register_renamed("bare_trait_object", "bare_trait_objects");
306 store.register_renamed("unstable_name_collision", "unstable_name_collisions");
307 store.register_renamed("unused_doc_comment", "unused_doc_comments");
308 store.register_renamed("async_idents", "keyword_idents");
309 store.register_renamed("exceeding_bitshifts", "arithmetic_overflow");
310 store.register_removed("unknown_features", "replaced by an error");
311 store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
312 store.register_removed("negate_unsigned", "cast a signed value instead");
313 store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
314 // Register lint group aliases.
315 store.register_group_alias("nonstandard_style", "bad_style");
316 // This was renamed to `raw_pointer_derive`, which was then removed,
317 // so it is also considered removed.
318 store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
319 store.register_removed("drop_with_repr_extern", "drop flags have been removed");
320 store.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
321 store.register_removed("deprecated_attr", "use `deprecated` instead");
322 store.register_removed(
323 "transmute_from_fn_item_types",
324 "always cast functions before transmuting them",
326 store.register_removed(
327 "hr_lifetime_in_assoc_type",
328 "converted into hard error, see issue #33685 \
329 <https://github.com/rust-lang/rust/issues/33685> for more information",
331 store.register_removed(
332 "inaccessible_extern_crate",
333 "converted into hard error, see issue #36886 \
334 <https://github.com/rust-lang/rust/issues/36886> for more information",
336 store.register_removed(
337 "super_or_self_in_global_path",
338 "converted into hard error, see issue #36888 \
339 <https://github.com/rust-lang/rust/issues/36888> for more information",
341 store.register_removed(
342 "overlapping_inherent_impls",
343 "converted into hard error, see issue #36889 \
344 <https://github.com/rust-lang/rust/issues/36889> for more information",
346 store.register_removed(
347 "illegal_floating_point_constant_pattern",
348 "converted into hard error, see issue #36890 \
349 <https://github.com/rust-lang/rust/issues/36890> for more information",
351 store.register_removed(
352 "illegal_struct_or_enum_constant_pattern",
353 "converted into hard error, see issue #36891 \
354 <https://github.com/rust-lang/rust/issues/36891> for more information",
356 store.register_removed(
357 "lifetime_underscore",
358 "converted into hard error, see issue #36892 \
359 <https://github.com/rust-lang/rust/issues/36892> for more information",
361 store.register_removed(
362 "extra_requirement_in_impl",
363 "converted into hard error, see issue #37166 \
364 <https://github.com/rust-lang/rust/issues/37166> for more information",
366 store.register_removed(
368 "converted into hard error, see issue #38260 \
369 <https://github.com/rust-lang/rust/issues/38260> for more information",
371 store.register_removed(
373 "converted into hard error, see issue #48950 \
374 <https://github.com/rust-lang/rust/issues/48950> for more information",
376 store.register_removed(
377 "resolve_trait_on_defaulted_unit",
378 "converted into hard error, see issue #48950 \
379 <https://github.com/rust-lang/rust/issues/48950> for more information",
381 store.register_removed(
382 "private_no_mangle_fns",
383 "no longer a warning, `#[no_mangle]` functions always exported",
385 store.register_removed(
386 "private_no_mangle_statics",
387 "no longer a warning, `#[no_mangle]` statics always exported",
389 store.register_removed("bad_repr", "replaced with a generic attribute input check");
390 store.register_removed(
391 "duplicate_matcher_binding_name",
392 "converted into hard error, see issue #57742 \
393 <https://github.com/rust-lang/rust/issues/57742> for more information",
395 store.register_removed(
396 "incoherent_fundamental_impls",
397 "converted into hard error, see issue #46205 \
398 <https://github.com/rust-lang/rust/issues/46205> for more information",
400 store.register_removed(
401 "legacy_constructor_visibility",
402 "converted into hard error, see issue #39207 \
403 <https://github.com/rust-lang/rust/issues/39207> for more information",
405 store.register_removed(
406 "legacy_directory_ownership",
407 "converted into hard error, see issue #37872 \
408 <https://github.com/rust-lang/rust/issues/37872> for more information",
410 store.register_removed(
411 "safe_extern_statics",
412 "converted into hard error, see issue #36247 \
413 <https://github.com/rust-lang/rust/issues/36247> for more information",
415 store.register_removed(
416 "parenthesized_params_in_types_and_modules",
417 "converted into hard error, see issue #42238 \
418 <https://github.com/rust-lang/rust/issues/42238> for more information",
420 store.register_removed(
421 "duplicate_macro_exports",
422 "converted into hard error, see issue #35896 \
423 <https://github.com/rust-lang/rust/issues/35896> for more information",
425 store.register_removed(
427 "converted into hard error, see issue #59014 \
428 <https://github.com/rust-lang/rust/issues/59014> for more information",
430 store.register_removed("plugin_as_library", "plugins have been deprecated and retired");
433 fn register_internals(store: &mut LintStore) {
434 store.register_lints(&DefaultHashTypes::get_lints());
435 store.register_early_pass(|| box DefaultHashTypes::new());
436 store.register_lints(&LintPassImpl::get_lints());
437 store.register_early_pass(|| box LintPassImpl);
438 store.register_lints(&TyTyKind::get_lints());
439 store.register_late_pass(|| box TyTyKind);
440 store.register_group(
445 LintId::of(DEFAULT_HASH_TYPES),
446 LintId::of(USAGE_OF_TY_TYKIND),
447 LintId::of(LINT_PASS_IMPL_WITHOUT_MACRO),
448 LintId::of(TY_PASS_BY_REFERENCE),
449 LintId::of(USAGE_OF_QUALIFIED_TY),