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(crate_visibility_modifier)]
34 #![feature(iter_order_by)]
35 #![feature(never_type)]
37 #![feature(or_patterns)]
38 #![recursion_limit = "256"]
41 extern crate rustc_middle
;
43 extern crate rustc_session
;
53 mod nonstandard_style
;
55 mod redundant_semicolon
;
61 use rustc_hir
::def_id
::LocalDefId
;
62 use rustc_middle
::ty
::query
::Providers
;
63 use rustc_middle
::ty
::TyCtxt
;
64 use rustc_session
::lint
::builtin
::{
65 BARE_TRAIT_OBJECTS
, BROKEN_INTRA_DOC_LINKS
, ELIDED_LIFETIMES_IN_PATHS
,
66 EXPLICIT_OUTLIVES_REQUIREMENTS
, INVALID_CODEBLOCK_ATTRIBUTES
, MISSING_DOC_CODE_EXAMPLES
,
69 use rustc_span
::symbol
::{Ident, Symbol}
;
72 use array_into_iter
::ArrayIntoIter
;
75 use non_ascii_idents
::*;
76 use nonstandard_style
::*;
77 use redundant_semicolon
::*;
81 /// Useful for other parts of the compiler / Clippy.
82 pub use builtin
::SoftLints
;
83 pub use context
::{CheckLintNameResult, EarlyContext, LateContext, LintContext, LintStore}
;
84 pub use early
::check_ast_crate
;
85 pub use late
::check_crate
;
86 pub use passes
::{EarlyLintPass, LateLintPass}
;
87 pub use rustc_session
::lint
::Level
::{self, *}
;
88 pub use rustc_session
::lint
::{BufferedEarlyLint, FutureIncompatibleInfo, Lint, LintId}
;
89 pub use rustc_session
::lint
::{LintArray, LintPass}
;
91 pub fn provide(providers
: &mut Providers
) {
92 levels
::provide(providers
);
93 *providers
= Providers { lint_mod, ..*providers }
;
96 fn lint_mod(tcx
: TyCtxt
<'_
>, module_def_id
: LocalDefId
) {
97 late
::late_lint_mod(tcx
, module_def_id
, BuiltinCombinedModuleLateLintPass
::new());
100 macro_rules
! pre_expansion_lint_passes
{
101 ($
macro:path
, $args
:tt
) => {
102 $
macro!($args
, [KeywordIdents
: KeywordIdents
,]);
106 macro_rules
! early_lint_passes
{
107 ($
macro:path
, $args
:tt
) => {
111 UnusedParens
: UnusedParens
,
112 UnusedBraces
: UnusedBraces
,
113 UnusedImportBraces
: UnusedImportBraces
,
114 UnsafeCode
: UnsafeCode
,
115 AnonymousParameters
: AnonymousParameters
,
116 EllipsisInclusiveRangePatterns
: EllipsisInclusiveRangePatterns
::default(),
117 NonCamelCaseTypes
: NonCamelCaseTypes
,
118 DeprecatedAttr
: DeprecatedAttr
::new(),
119 WhileTrue
: WhileTrue
,
120 NonAsciiIdents
: NonAsciiIdents
,
121 IncompleteFeatures
: IncompleteFeatures
,
122 RedundantSemicolons
: RedundantSemicolons
,
123 UnusedDocComment
: UnusedDocComment
,
129 macro_rules
! declare_combined_early_pass
{
130 ([$name
:ident
], $passes
:tt
) => (
131 early_lint_methods
!(declare_combined_early_lint_pass
, [pub $name
, $passes
]);
135 pre_expansion_lint_passes
!(declare_combined_early_pass
, [BuiltinCombinedPreExpansionLintPass
]);
136 early_lint_passes
!(declare_combined_early_pass
, [BuiltinCombinedEarlyLintPass
]);
138 macro_rules
! late_lint_passes
{
139 ($
macro:path
, $args
:tt
) => {
143 // FIXME: Look into regression when this is used as a module lint
144 // May Depend on constants elsewhere
145 UnusedBrokenConst
: UnusedBrokenConst
,
146 // Uses attr::is_used which is untracked, can't be an incremental module pass.
147 UnusedAttributes
: UnusedAttributes
::new(),
148 // Needs to run after UnusedAttributes as it marks all `feature` attributes as used.
149 UnstableFeatures
: UnstableFeatures
,
150 // Tracks state across modules
151 UnnameableTestItems
: UnnameableTestItems
::new(),
152 // Tracks attributes of parents
153 MissingDoc
: MissingDoc
::new(),
154 // Depends on access levels
155 // FIXME: Turn the computation of types which implement Debug into a query
156 // and change this to a module lint pass
157 MissingDebugImplementations
: MissingDebugImplementations
::default(),
158 ArrayIntoIter
: ArrayIntoIter
,
159 ClashingExternDeclarations
: ClashingExternDeclarations
::new(),
165 macro_rules
! late_lint_mod_passes
{
166 ($
macro:path
, $args
:tt
) => {
170 HardwiredLints
: HardwiredLints
,
171 ImproperCTypesDeclarations
: ImproperCTypesDeclarations
,
172 ImproperCTypesDefinitions
: ImproperCTypesDefinitions
,
173 VariantSizeDifferences
: VariantSizeDifferences
,
174 BoxPointers
: BoxPointers
,
175 PathStatements
: PathStatements
,
176 // Depends on referenced function signatures in expressions
177 UnusedResults
: UnusedResults
,
178 NonUpperCaseGlobals
: NonUpperCaseGlobals
,
179 NonShorthandFieldPatterns
: NonShorthandFieldPatterns
,
180 UnusedAllocation
: UnusedAllocation
,
181 // Depends on types used in type definitions
182 MissingCopyImplementations
: MissingCopyImplementations
,
183 // Depends on referenced function signatures in expressions
184 MutableTransmutes
: MutableTransmutes
,
185 TypeAliasBounds
: TypeAliasBounds
,
186 TrivialConstraints
: TrivialConstraints
,
187 TypeLimits
: TypeLimits
::new(),
188 NonSnakeCase
: NonSnakeCase
,
189 InvalidNoMangleItems
: InvalidNoMangleItems
,
190 // Depends on access levels
191 UnreachablePub
: UnreachablePub
,
192 ExplicitOutlivesRequirements
: ExplicitOutlivesRequirements
,
193 InvalidValue
: InvalidValue
,
199 macro_rules
! declare_combined_late_pass
{
200 ([$v
:vis $name
:ident
], $passes
:tt
) => (
201 late_lint_methods
!(declare_combined_late_lint_pass
, [$v $name
, $passes
], ['tcx
]);
205 // FIXME: Make a separate lint type which do not require typeck tables
206 late_lint_passes
!(declare_combined_late_pass
, [pub BuiltinCombinedLateLintPass
]);
208 late_lint_mod_passes
!(declare_combined_late_pass
, [BuiltinCombinedModuleLateLintPass
]);
210 pub fn new_lint_store(no_interleave_lints
: bool
, internal_lints
: bool
) -> LintStore
{
211 let mut lint_store
= LintStore
::new();
213 register_builtins(&mut lint_store
, no_interleave_lints
);
215 register_internals(&mut lint_store
);
221 /// Tell the `LintStore` about all the built-in lints (the ones
222 /// defined in this crate and the ones defined in
223 /// `rustc_session::lint::builtin`).
224 fn register_builtins(store
: &mut LintStore
, no_interleave_lints
: bool
) {
225 macro_rules
! add_lint_group
{
226 ($name
:expr
, $
($lint
:ident
),*) => (
227 store
.register_group(false, $name
, None
, vec
![$
(LintId
::of($lint
)),*]);
231 macro_rules
! register_pass
{
232 ($method
:ident
, $ty
:ident
, $constructor
:expr
) => {
233 store
.register_lints(&$ty
::get_lints());
234 store
.$
method(|| box $constructor
);
238 macro_rules
! register_passes
{
239 ($method
:ident
, [$
($passes
:ident
: $constructor
:expr
,)*]) => (
241 register_pass
!($method
, $passes
, $constructor
);
246 if no_interleave_lints
{
247 pre_expansion_lint_passes
!(register_passes
, register_pre_expansion_pass
);
248 early_lint_passes
!(register_passes
, register_early_pass
);
249 late_lint_passes
!(register_passes
, register_late_pass
);
250 late_lint_mod_passes
!(register_passes
, register_late_mod_pass
);
252 store
.register_lints(&BuiltinCombinedPreExpansionLintPass
::get_lints());
253 store
.register_lints(&BuiltinCombinedEarlyLintPass
::get_lints());
254 store
.register_lints(&BuiltinCombinedModuleLateLintPass
::get_lints());
255 store
.register_lints(&BuiltinCombinedLateLintPass
::get_lints());
260 NON_CAMEL_CASE_TYPES
,
262 NON_UPPER_CASE_GLOBALS
273 UNREACHABLE_PATTERNS
,
274 OVERLAPPING_PATTERNS
,
282 UNUSED_EXTERN_CRATES
,
293 UNUSED_EXTERN_CRATES
,
294 ELLIPSIS_INCLUSIVE_RANGE_PATTERNS
,
295 ELIDED_LIFETIMES_IN_PATHS
,
296 EXPLICIT_OUTLIVES_REQUIREMENTS
// FIXME(#52665, #47816) not always applicable and not all
297 // macros are ready for this yet.
300 // FIXME macro crates are not up for this yet, too much
301 // breakage is seen if we try to encourage this lint.
302 // MACRO_USE_EXTERN_CRATE
307 BROKEN_INTRA_DOC_LINKS
,
308 PRIVATE_INTRA_DOC_LINKS
,
309 INVALID_CODEBLOCK_ATTRIBUTES
,
310 MISSING_DOC_CODE_EXAMPLES
,
314 // Register renamed and removed lints.
315 store
.register_renamed("single_use_lifetime", "single_use_lifetimes");
316 store
.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
317 store
.register_renamed("bare_trait_object", "bare_trait_objects");
318 store
.register_renamed("unstable_name_collision", "unstable_name_collisions");
319 store
.register_renamed("unused_doc_comment", "unused_doc_comments");
320 store
.register_renamed("async_idents", "keyword_idents");
321 store
.register_renamed("exceeding_bitshifts", "arithmetic_overflow");
322 store
.register_renamed("redundant_semicolon", "redundant_semicolons");
323 store
.register_renamed("intra_doc_link_resolution_failure", "broken_intra_doc_links");
324 store
.register_removed("unknown_features", "replaced by an error");
325 store
.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
326 store
.register_removed("negate_unsigned", "cast a signed value instead");
327 store
.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
328 // Register lint group aliases.
329 store
.register_group_alias("nonstandard_style", "bad_style");
330 // This was renamed to `raw_pointer_derive`, which was then removed,
331 // so it is also considered removed.
332 store
.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
333 store
.register_removed("drop_with_repr_extern", "drop flags have been removed");
334 store
.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
335 store
.register_removed("deprecated_attr", "use `deprecated` instead");
336 store
.register_removed(
337 "transmute_from_fn_item_types",
338 "always cast functions before transmuting them",
340 store
.register_removed(
341 "hr_lifetime_in_assoc_type",
342 "converted into hard error, see issue #33685 \
343 <https://github.com/rust-lang/rust/issues/33685> for more information",
345 store
.register_removed(
346 "inaccessible_extern_crate",
347 "converted into hard error, see issue #36886 \
348 <https://github.com/rust-lang/rust/issues/36886> for more information",
350 store
.register_removed(
351 "super_or_self_in_global_path",
352 "converted into hard error, see issue #36888 \
353 <https://github.com/rust-lang/rust/issues/36888> for more information",
355 store
.register_removed(
356 "overlapping_inherent_impls",
357 "converted into hard error, see issue #36889 \
358 <https://github.com/rust-lang/rust/issues/36889> for more information",
360 store
.register_removed(
361 "illegal_floating_point_constant_pattern",
362 "converted into hard error, see issue #36890 \
363 <https://github.com/rust-lang/rust/issues/36890> for more information",
365 store
.register_removed(
366 "illegal_struct_or_enum_constant_pattern",
367 "converted into hard error, see issue #36891 \
368 <https://github.com/rust-lang/rust/issues/36891> for more information",
370 store
.register_removed(
371 "lifetime_underscore",
372 "converted into hard error, see issue #36892 \
373 <https://github.com/rust-lang/rust/issues/36892> for more information",
375 store
.register_removed(
376 "extra_requirement_in_impl",
377 "converted into hard error, see issue #37166 \
378 <https://github.com/rust-lang/rust/issues/37166> for more information",
380 store
.register_removed(
382 "converted into hard error, see issue #38260 \
383 <https://github.com/rust-lang/rust/issues/38260> for more information",
385 store
.register_removed(
387 "converted into hard error, see issue #48950 \
388 <https://github.com/rust-lang/rust/issues/48950> for more information",
390 store
.register_removed(
391 "resolve_trait_on_defaulted_unit",
392 "converted into hard error, see issue #48950 \
393 <https://github.com/rust-lang/rust/issues/48950> for more information",
395 store
.register_removed(
396 "private_no_mangle_fns",
397 "no longer a warning, `#[no_mangle]` functions always exported",
399 store
.register_removed(
400 "private_no_mangle_statics",
401 "no longer a warning, `#[no_mangle]` statics always exported",
403 store
.register_removed("bad_repr", "replaced with a generic attribute input check");
404 store
.register_removed(
405 "duplicate_matcher_binding_name",
406 "converted into hard error, see issue #57742 \
407 <https://github.com/rust-lang/rust/issues/57742> for more information",
409 store
.register_removed(
410 "incoherent_fundamental_impls",
411 "converted into hard error, see issue #46205 \
412 <https://github.com/rust-lang/rust/issues/46205> for more information",
414 store
.register_removed(
415 "legacy_constructor_visibility",
416 "converted into hard error, see issue #39207 \
417 <https://github.com/rust-lang/rust/issues/39207> for more information",
419 store
.register_removed(
420 "legacy_directory_ownership",
421 "converted into hard error, see issue #37872 \
422 <https://github.com/rust-lang/rust/issues/37872> for more information",
424 store
.register_removed(
425 "safe_extern_statics",
426 "converted into hard error, see issue #36247 \
427 <https://github.com/rust-lang/rust/issues/36247> for more information",
429 store
.register_removed(
430 "parenthesized_params_in_types_and_modules",
431 "converted into hard error, see issue #42238 \
432 <https://github.com/rust-lang/rust/issues/42238> for more information",
434 store
.register_removed(
435 "duplicate_macro_exports",
436 "converted into hard error, see issue #35896 \
437 <https://github.com/rust-lang/rust/issues/35896> for more information",
439 store
.register_removed(
441 "converted into hard error, see issue #59014 \
442 <https://github.com/rust-lang/rust/issues/59014> for more information",
444 store
.register_removed("plugin_as_library", "plugins have been deprecated and retired");
447 fn register_internals(store
: &mut LintStore
) {
448 store
.register_lints(&DefaultHashTypes
::get_lints());
449 store
.register_early_pass(|| box DefaultHashTypes
::new());
450 store
.register_lints(&LintPassImpl
::get_lints());
451 store
.register_early_pass(|| box LintPassImpl
);
452 store
.register_lints(&TyTyKind
::get_lints());
453 store
.register_late_pass(|| box TyTyKind
);
454 store
.register_group(
459 LintId
::of(DEFAULT_HASH_TYPES
),
460 LintId
::of(USAGE_OF_TY_TYKIND
),
461 LintId
::of(LINT_PASS_IMPL_WITHOUT_MACRO
),
462 LintId
::of(TY_PASS_BY_REFERENCE
),
463 LintId
::of(USAGE_OF_QUALIFIED_TY
),