src/librustc_lint/lib.rs

   1 //! # Lints in the Rust compiler
   2 //!
   3 //! This currently only contains the definitions and implementations
   4 //! of most of the lints that `rustc` supports directly, it does not
   5 //! contain the infrastructure for defining/registering lints. That is
   6 //! available in `rustc::lint` and `rustc_driver::plugin` respectively.
   7 //!
   8 //! ## Note
   9 //!
  10 //! This API is completely unstable and subject to change.
  11
  12 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
  13 #![cfg_attr(test, feature(test))]
  14 #![feature(bool_to_option)]
  15 #![feature(box_patterns)]
  16 #![feature(box_syntax)]
  17 #![feature(crate_visibility_modifier)]
  18 #![feature(never_type)]
  19 #![feature(nll)]
  20 #![recursion_limit = "256"]
  21
  22 #[macro_use]
  23 extern crate rustc;
  24 #[macro_use]
  25 extern crate rustc_session;
  26
  27 mod array_into_iter;
  28 pub mod builtin;
  29 mod context;
  30 mod early;
  31 mod internal;
  32 mod late;
  33 mod levels;
  34 mod non_ascii_idents;
  35 mod nonstandard_style;
  36 mod passes;
  37 mod redundant_semicolon;
  38 mod types;
  39 mod unused;
  40
  41 use rustc::ty::query::Providers;
  42 use rustc::ty::TyCtxt;
  43 use rustc_hir as hir;
  44 use rustc_hir::def_id::DefId;
  45 use rustc_session::lint::builtin::{
  46     BARE_TRAIT_OBJECTS, ELIDED_LIFETIMES_IN_PATHS, EXPLICIT_OUTLIVES_REQUIREMENTS,
  47     INTRA_DOC_LINK_RESOLUTION_FAILURE, MISSING_DOC_CODE_EXAMPLES, PRIVATE_DOC_TESTS,
  48 };
  49 use rustc_span::Span;
  50 use syntax::ast;
  51
  52 use array_into_iter::ArrayIntoIter;
  53 use builtin::*;
  54 use internal::*;
  55 use non_ascii_idents::*;
  56 use nonstandard_style::*;
  57 use redundant_semicolon::*;
  58 use types::*;
  59 use unused::*;
  60
  61 /// Useful for other parts of the compiler / Clippy.
  62 pub use builtin::SoftLints;
  63 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
  64 pub use early::check_ast_crate;
  65 pub use late::check_crate;
  66 pub use passes::{EarlyLintPass, LateLintPass};
  67 pub use rustc_session::lint::Level::{self, *};
  68 pub use rustc_session::lint::{BufferedEarlyLint, FutureIncompatibleInfo, Lint, LintId};
  69 pub use rustc_session::lint::{LintArray, LintPass};
  70
  71 pub fn provide(providers: &mut Providers<'_>) {
  72     levels::provide(providers);
  73     *providers = Providers { lint_mod, ..*providers };
  74 }
  75
  76 fn lint_mod(tcx: TyCtxt<'_>, module_def_id: DefId) {
  77     late::late_lint_mod(tcx, module_def_id, BuiltinCombinedModuleLateLintPass::new());
  78 }
  79
  80 macro_rules! pre_expansion_lint_passes {
  81     ($macro:path, $args:tt) => {
  82         $macro!($args, [KeywordIdents: KeywordIdents, UnusedDocComment: UnusedDocComment,]);
  83     };
  84 }
  85
  86 macro_rules! early_lint_passes {
  87     ($macro:path, $args:tt) => {
  88         $macro!(
  89             $args,
  90             [
  91                 UnusedParens: UnusedParens,
  92                 UnusedImportBraces: UnusedImportBraces,
  93                 UnsafeCode: UnsafeCode,
  94                 AnonymousParameters: AnonymousParameters,
  95                 EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns::default(),
  96                 NonCamelCaseTypes: NonCamelCaseTypes,
  97                 DeprecatedAttr: DeprecatedAttr::new(),
  98                 WhileTrue: WhileTrue,
  99                 NonAsciiIdents: NonAsciiIdents,
 100                 IncompleteFeatures: IncompleteFeatures,
 101                 RedundantSemicolon: RedundantSemicolon,
 102             ]
 103         );
 104     };
 105 }
 106
 107 macro_rules! declare_combined_early_pass {
 108     ([$name:ident], $passes:tt) => (
 109         early_lint_methods!(declare_combined_early_lint_pass, [pub $name, $passes]);
 110     )
 111 }
 112
 113 pre_expansion_lint_passes!(declare_combined_early_pass, [BuiltinCombinedPreExpansionLintPass]);
 114 early_lint_passes!(declare_combined_early_pass, [BuiltinCombinedEarlyLintPass]);
 115
 116 macro_rules! late_lint_passes {
 117     ($macro:path, $args:tt) => {
 118         $macro!(
 119             $args,
 120             [
 121                 // FIXME: Look into regression when this is used as a module lint
 122                 // May Depend on constants elsewhere
 123                 UnusedBrokenConst: UnusedBrokenConst,
 124                 // Uses attr::is_used which is untracked, can't be an incremental module pass.
 125                 UnusedAttributes: UnusedAttributes::new(),
 126                 // Needs to run after UnusedAttributes as it marks all `feature` attributes as used.
 127                 UnstableFeatures: UnstableFeatures,
 128                 // Tracks state across modules
 129                 UnnameableTestItems: UnnameableTestItems::new(),
 130                 // Tracks attributes of parents
 131                 MissingDoc: MissingDoc::new(),
 132                 // Depends on access levels
 133                 // FIXME: Turn the computation of types which implement Debug into a query
 134                 // and change this to a module lint pass
 135                 MissingDebugImplementations: MissingDebugImplementations::default(),
 136                 ArrayIntoIter: ArrayIntoIter,
 137             ]
 138         );
 139     };
 140 }
 141
 142 macro_rules! late_lint_mod_passes {
 143     ($macro:path, $args:tt) => {
 144         $macro!(
 145             $args,
 146             [
 147                 HardwiredLints: HardwiredLints,
 148                 ImproperCTypes: ImproperCTypes,
 149                 VariantSizeDifferences: VariantSizeDifferences,
 150                 BoxPointers: BoxPointers,
 151                 PathStatements: PathStatements,
 152                 // Depends on referenced function signatures in expressions
 153                 UnusedResults: UnusedResults,
 154                 NonUpperCaseGlobals: NonUpperCaseGlobals,
 155                 NonShorthandFieldPatterns: NonShorthandFieldPatterns,
 156                 UnusedAllocation: UnusedAllocation,
 157                 // Depends on types used in type definitions
 158                 MissingCopyImplementations: MissingCopyImplementations,
 159                 // Depends on referenced function signatures in expressions
 160                 MutableTransmutes: MutableTransmutes,
 161                 TypeAliasBounds: TypeAliasBounds,
 162                 TrivialConstraints: TrivialConstraints,
 163                 TypeLimits: TypeLimits::new(),
 164                 NonSnakeCase: NonSnakeCase,
 165                 InvalidNoMangleItems: InvalidNoMangleItems,
 166                 // Depends on access levels
 167                 UnreachablePub: UnreachablePub,
 168                 ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
 169                 InvalidValue: InvalidValue,
 170             ]
 171         );
 172     };
 173 }
 174
 175 macro_rules! declare_combined_late_pass {
 176     ([$v:vis $name:ident], $passes:tt) => (
 177         late_lint_methods!(declare_combined_late_lint_pass, [$v $name, $passes], ['tcx]);
 178     )
 179 }
 180
 181 // FIXME: Make a separate lint type which do not require typeck tables
 182 late_lint_passes!(declare_combined_late_pass, [pub BuiltinCombinedLateLintPass]);
 183
 184 late_lint_mod_passes!(declare_combined_late_pass, [BuiltinCombinedModuleLateLintPass]);
 185
 186 pub fn new_lint_store(no_interleave_lints: bool, internal_lints: bool) -> LintStore {
 187     let mut lint_store = LintStore::new();
 188
 189     register_builtins(&mut lint_store, no_interleave_lints);
 190     if internal_lints {
 191         register_internals(&mut lint_store);
 192     }
 193
 194     lint_store
 195 }
 196
 197 /// Tell the `LintStore` about all the built-in lints (the ones
 198 /// defined in this crate and the ones defined in
 199 /// `rustc::lint::builtin`).
 200 fn register_builtins(store: &mut LintStore, no_interleave_lints: bool) {
 201     macro_rules! add_lint_group {
 202         ($name:expr, $($lint:ident),*) => (
 203             store.register_group(false, $name, None, vec![$(LintId::of($lint)),*]);
 204         )
 205     }
 206
 207     macro_rules! register_pass {
 208         ($method:ident, $ty:ident, $constructor:expr) => {
 209             store.register_lints(&$ty::get_lints());
 210             store.$method(|| box $constructor);
 211         };
 212     }
 213
 214     macro_rules! register_passes {
 215         ($method:ident, [$($passes:ident: $constructor:expr,)*]) => (
 216             $(
 217                 register_pass!($method, $passes, $constructor);
 218             )*
 219         )
 220     }
 221
 222     if no_interleave_lints {
 223         pre_expansion_lint_passes!(register_passes, register_pre_expansion_pass);
 224         early_lint_passes!(register_passes, register_early_pass);
 225         late_lint_passes!(register_passes, register_late_pass);
 226         late_lint_mod_passes!(register_passes, register_late_mod_pass);
 227     } else {
 228         store.register_lints(&BuiltinCombinedPreExpansionLintPass::get_lints());
 229         store.register_lints(&BuiltinCombinedEarlyLintPass::get_lints());
 230         store.register_lints(&BuiltinCombinedModuleLateLintPass::get_lints());
 231         store.register_lints(&BuiltinCombinedLateLintPass::get_lints());
 232     }
 233
 234     add_lint_group!(
 235         "nonstandard_style",
 236         NON_CAMEL_CASE_TYPES,
 237         NON_SNAKE_CASE,
 238         NON_UPPER_CASE_GLOBALS
 239     );
 240
 241     add_lint_group!(
 242         "unused",
 243         UNUSED_IMPORTS,
 244         UNUSED_VARIABLES,
 245         UNUSED_ASSIGNMENTS,
 246         DEAD_CODE,
 247         UNUSED_MUT,
 248         UNREACHABLE_CODE,
 249         UNREACHABLE_PATTERNS,
 250         OVERLAPPING_PATTERNS,
 251         UNUSED_MUST_USE,
 252         UNUSED_UNSAFE,
 253         PATH_STATEMENTS,
 254         UNUSED_ATTRIBUTES,
 255         UNUSED_MACROS,
 256         UNUSED_ALLOCATION,
 257         UNUSED_DOC_COMMENTS,
 258         UNUSED_EXTERN_CRATES,
 259         UNUSED_FEATURES,
 260         UNUSED_LABELS,
 261         UNUSED_PARENS
 262     );
 263
 264     add_lint_group!(
 265         "rust_2018_idioms",
 266         BARE_TRAIT_OBJECTS,
 267         UNUSED_EXTERN_CRATES,
 268         ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
 269         ELIDED_LIFETIMES_IN_PATHS,
 270         EXPLICIT_OUTLIVES_REQUIREMENTS // FIXME(#52665, #47816) not always applicable and not all
 271                                        // macros are ready for this yet.
 272                                        // UNREACHABLE_PUB,
 273
 274                                        // FIXME macro crates are not up for this yet, too much
 275                                        // breakage is seen if we try to encourage this lint.
 276                                        // MACRO_USE_EXTERN_CRATE
 277     );
 278
 279     add_lint_group!(
 280         "rustdoc",
 281         INTRA_DOC_LINK_RESOLUTION_FAILURE,
 282         MISSING_DOC_CODE_EXAMPLES,
 283         PRIVATE_DOC_TESTS
 284     );
 285
 286     // Register renamed and removed lints.
 287     store.register_renamed("single_use_lifetime", "single_use_lifetimes");
 288     store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
 289     store.register_renamed("bare_trait_object", "bare_trait_objects");
 290     store.register_renamed("unstable_name_collision", "unstable_name_collisions");
 291     store.register_renamed("unused_doc_comment", "unused_doc_comments");
 292     store.register_renamed("async_idents", "keyword_idents");
 293     store.register_removed("unknown_features", "replaced by an error");
 294     store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
 295     store.register_removed("negate_unsigned", "cast a signed value instead");
 296     store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
 297     // Register lint group aliases.
 298     store.register_group_alias("nonstandard_style", "bad_style");
 299     // This was renamed to `raw_pointer_derive`, which was then removed,
 300     // so it is also considered removed.
 301     store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
 302     store.register_removed("drop_with_repr_extern", "drop flags have been removed");
 303     store.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
 304     store.register_removed("deprecated_attr", "use `deprecated` instead");
 305     store.register_removed(
 306         "transmute_from_fn_item_types",
 307         "always cast functions before transmuting them",
 308     );
 309     store.register_removed(
 310         "hr_lifetime_in_assoc_type",
 311         "converted into hard error, see https://github.com/rust-lang/rust/issues/33685",
 312     );
 313     store.register_removed(
 314         "inaccessible_extern_crate",
 315         "converted into hard error, see https://github.com/rust-lang/rust/issues/36886",
 316     );
 317     store.register_removed(
 318         "super_or_self_in_global_path",
 319         "converted into hard error, see https://github.com/rust-lang/rust/issues/36888",
 320     );
 321     store.register_removed(
 322         "overlapping_inherent_impls",
 323         "converted into hard error, see https://github.com/rust-lang/rust/issues/36889",
 324     );
 325     store.register_removed(
 326         "illegal_floating_point_constant_pattern",
 327         "converted into hard error, see https://github.com/rust-lang/rust/issues/36890",
 328     );
 329     store.register_removed(
 330         "illegal_struct_or_enum_constant_pattern",
 331         "converted into hard error, see https://github.com/rust-lang/rust/issues/36891",
 332     );
 333     store.register_removed(
 334         "lifetime_underscore",
 335         "converted into hard error, see https://github.com/rust-lang/rust/issues/36892",
 336     );
 337     store.register_removed(
 338         "extra_requirement_in_impl",
 339         "converted into hard error, see https://github.com/rust-lang/rust/issues/37166",
 340     );
 341     store.register_removed(
 342         "legacy_imports",
 343         "converted into hard error, see https://github.com/rust-lang/rust/issues/38260",
 344     );
 345     store.register_removed(
 346         "coerce_never",
 347         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950",
 348     );
 349     store.register_removed(
 350         "resolve_trait_on_defaulted_unit",
 351         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950",
 352     );
 353     store.register_removed(
 354         "private_no_mangle_fns",
 355         "no longer a warning, `#[no_mangle]` functions always exported",
 356     );
 357     store.register_removed(
 358         "private_no_mangle_statics",
 359         "no longer a warning, `#[no_mangle]` statics always exported",
 360     );
 361     store.register_removed("bad_repr", "replaced with a generic attribute input check");
 362     store.register_removed(
 363         "duplicate_matcher_binding_name",
 364         "converted into hard error, see https://github.com/rust-lang/rust/issues/57742",
 365     );
 366     store.register_removed(
 367         "incoherent_fundamental_impls",
 368         "converted into hard error, see https://github.com/rust-lang/rust/issues/46205",
 369     );
 370     store.register_removed(
 371         "legacy_constructor_visibility",
 372         "converted into hard error, see https://github.com/rust-lang/rust/issues/39207",
 373     );
 374     store.register_removed(
 375         "legacy_directory_ownership",
 376         "converted into hard error, see https://github.com/rust-lang/rust/issues/37872",
 377     );
 378     store.register_removed(
 379         "safe_extern_statics",
 380         "converted into hard error, see https://github.com/rust-lang/rust/issues/36247",
 381     );
 382     store.register_removed(
 383         "parenthesized_params_in_types_and_modules",
 384         "converted into hard error, see https://github.com/rust-lang/rust/issues/42238",
 385     );
 386     store.register_removed(
 387         "duplicate_macro_exports",
 388         "converted into hard error, see https://github.com/rust-lang/rust/issues/35896",
 389     );
 390     store.register_removed(
 391         "nested_impl_trait",
 392         "converted into hard error, see https://github.com/rust-lang/rust/issues/59014",
 393     );
 394     store.register_removed("plugin_as_library", "plugins have been deprecated and retired");
 395 }
 396
 397 fn register_internals(store: &mut LintStore) {
 398     store.register_lints(&DefaultHashTypes::get_lints());
 399     store.register_early_pass(|| box DefaultHashTypes::new());
 400     store.register_lints(&LintPassImpl::get_lints());
 401     store.register_early_pass(|| box LintPassImpl);
 402     store.register_lints(&TyTyKind::get_lints());
 403     store.register_late_pass(|| box TyTyKind);
 404     store.register_group(
 405         false,
 406         "rustc::internal",
 407         None,
 408         vec![
 409             LintId::of(DEFAULT_HASH_TYPES),
 410             LintId::of(USAGE_OF_TY_TYKIND),
 411             LintId::of(LINT_PASS_IMPL_WITHOUT_MACRO),
 412             LintId::of(TY_PASS_BY_REFERENCE),
 413             LintId::of(USAGE_OF_QUALIFIED_TY),
 414         ],
 415     );
 416 }