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