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_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
  14 #![cfg_attr(test, feature(test))]
  15 #![feature(box_patterns)]
  16 #![feature(box_syntax)]
  17 #![feature(nll)]
  18 #![feature(rustc_diagnostic_macros)]
  19
  20 #![recursion_limit="256"]
  21
  22 #![deny(rust_2018_idioms)]
  23 #![deny(unused_lifetimes)]
  24
  25 #[macro_use]
  26 extern crate rustc;
  27
  28 mod error_codes;
  29 mod nonstandard_style;
  30 pub mod builtin;
  31 mod types;
  32 mod unused;
  33 mod non_ascii_idents;
  34
  35 use rustc::lint;
  36 use rustc::lint::{EarlyContext, LateContext, LateLintPass, EarlyLintPass, LintPass, LintArray};
  37 use rustc::lint::builtin::{
  38     BARE_TRAIT_OBJECTS,
  39     ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  40     ELIDED_LIFETIMES_IN_PATHS,
  41     EXPLICIT_OUTLIVES_REQUIREMENTS,
  42     INTRA_DOC_LINK_RESOLUTION_FAILURE,
  43     MISSING_DOC_CODE_EXAMPLES,
  44     PRIVATE_DOC_TESTS,
  45     parser::ILL_FORMED_ATTRIBUTE_INPUT,
  46 };
  47 use rustc::session;
  48 use rustc::hir;
  49 use rustc::hir::def_id::DefId;
  50 use rustc::ty::query::Providers;
  51 use rustc::ty::TyCtxt;
  52
  53 use syntax::ast;
  54 use syntax::edition::Edition;
  55 use syntax_pos::Span;
  56
  57 use session::Session;
  58 use lint::LintId;
  59 use lint::FutureIncompatibleInfo;
  60
  61 use nonstandard_style::*;
  62 use builtin::*;
  63 use types::*;
  64 use unused::*;
  65 use non_ascii_idents::*;
  66 use rustc::lint::internal::*;
  67
  68 /// Useful for other parts of the compiler.
  69 pub use builtin::SoftLints;
  70
  71 pub fn provide(providers: &mut Providers<'_>) {
  72     *providers = Providers {
  73         lint_mod,
  74         ..*providers
  75     };
  76 }
  77
  78 fn lint_mod(tcx: TyCtxt<'_>, module_def_id: DefId) {
  79     lint::late_lint_mod(tcx, module_def_id, BuiltinCombinedModuleLateLintPass::new());
  80 }
  81
  82 macro_rules! pre_expansion_lint_passes {
  83     ($macro:path, $args:tt) => (
  84         $macro!($args, [
  85             KeywordIdents: KeywordIdents,
  86             UnusedDocComment: UnusedDocComment,
  87         ]);
  88     )
  89 }
  90
  91 macro_rules! early_lint_passes {
  92     ($macro:path, $args:tt) => (
  93         $macro!($args, [
  94             UnusedParens: UnusedParens,
  95             UnusedImportBraces: UnusedImportBraces,
  96             UnsafeCode: UnsafeCode,
  97             AnonymousParameters: AnonymousParameters,
  98             EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns::default(),
  99             NonCamelCaseTypes: NonCamelCaseTypes,
 100             DeprecatedAttr: DeprecatedAttr::new(),
 101             WhileTrue: WhileTrue,
 102             NonAsciiIdents: NonAsciiIdents,
 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         $macro!($args, [
 119             // FIXME: Look into regression when this is used as a module lint
 120             // May Depend on constants elsewhere
 121             UnusedBrokenConst: UnusedBrokenConst,
 122
 123             // Uses attr::is_used which is untracked, can't be an incremental module pass.
 124             UnusedAttributes: UnusedAttributes::new(),
 125
 126             // Needs to run after UnusedAttributes as it marks all `feature` attributes as used.
 127             UnstableFeatures: UnstableFeatures,
 128
 129             // Tracks state across modules
 130             UnnameableTestItems: UnnameableTestItems::new(),
 131
 132             // Tracks attributes of parents
 133             MissingDoc: MissingDoc::new(),
 134
 135             // Depends on access levels
 136             // FIXME: Turn the computation of types which implement Debug into a query
 137             // and change this to a module lint pass
 138             MissingDebugImplementations: MissingDebugImplementations::default(),
 139         ]);
 140     )
 141 }
 142
 143 macro_rules! late_lint_mod_passes {
 144     ($macro:path, $args:tt) => (
 145         $macro!($args, [
 146             HardwiredLints: HardwiredLints,
 147             ImproperCTypes: ImproperCTypes,
 148             VariantSizeDifferences: VariantSizeDifferences,
 149             BoxPointers: BoxPointers,
 150             PathStatements: PathStatements,
 151
 152             // Depends on referenced function signatures in expressions
 153             UnusedResults: UnusedResults,
 154
 155             NonUpperCaseGlobals: NonUpperCaseGlobals,
 156             NonShorthandFieldPatterns: NonShorthandFieldPatterns,
 157             UnusedAllocation: UnusedAllocation,
 158
 159             // Depends on types used in type definitions
 160             MissingCopyImplementations: MissingCopyImplementations,
 161
 162             PluginAsLibrary: PluginAsLibrary,
 163
 164             // Depends on referenced function signatures in expressions
 165             MutableTransmutes: MutableTransmutes,
 166
 167             // Depends on types of fields, checks if they implement Drop
 168             UnionsWithDropFields: UnionsWithDropFields,
 169
 170             TypeAliasBounds: TypeAliasBounds,
 171
 172             TrivialConstraints: TrivialConstraints,
 173             TypeLimits: TypeLimits::new(),
 174
 175             NonSnakeCase: NonSnakeCase,
 176             InvalidNoMangleItems: InvalidNoMangleItems,
 177
 178             // Depends on access levels
 179             UnreachablePub: UnreachablePub,
 180
 181             ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
 182         ]);
 183     )
 184 }
 185
 186 macro_rules! declare_combined_late_pass {
 187     ([$v:vis $name:ident], $passes:tt) => (
 188         late_lint_methods!(declare_combined_late_lint_pass, [$v $name, $passes], ['tcx]);
 189     )
 190 }
 191
 192 // FIXME: Make a separate lint type which do not require typeck tables
 193 late_lint_passes!(declare_combined_late_pass, [pub BuiltinCombinedLateLintPass]);
 194
 195 late_lint_mod_passes!(declare_combined_late_pass, [BuiltinCombinedModuleLateLintPass]);
 196
 197 /// Tell the `LintStore` about all the built-in lints (the ones
 198 /// defined in this crate and the ones defined in
 199 /// `rustc::lint::builtin`).
 200 pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
 201     macro_rules! add_lint_group {
 202         ($sess:ident, $name:expr, $($lint:ident),*) => (
 203             store.register_group($sess, false, $name, None, vec![$(LintId::of($lint)),*]);
 204         )
 205     }
 206
 207     macro_rules! register_pass {
 208         ($method:ident, $constructor:expr, [$($args:expr),*]) => (
 209             store.$method(sess, false, false, $($args,)* box $constructor);
 210         )
 211     }
 212
 213     macro_rules! register_passes {
 214         ([$method:ident, $args:tt], [$($passes:ident: $constructor:expr,)*]) => (
 215             $(
 216                 register_pass!($method, $constructor, $args);
 217             )*
 218         )
 219     }
 220
 221     if sess.map(|sess| sess.opts.debugging_opts.no_interleave_lints).unwrap_or(false) {
 222         pre_expansion_lint_passes!(register_passes, [register_pre_expansion_pass, []]);
 223         early_lint_passes!(register_passes, [register_early_pass, []]);
 224         late_lint_passes!(register_passes, [register_late_pass, [false]]);
 225         late_lint_mod_passes!(register_passes, [register_late_pass, [true]]);
 226     } else {
 227         store.register_pre_expansion_pass(
 228             sess,
 229             false,
 230             true,
 231             box BuiltinCombinedPreExpansionLintPass::new()
 232         );
 233         store.register_early_pass(sess, false, true, box BuiltinCombinedEarlyLintPass::new());
 234         store.register_late_pass(
 235             sess, false, true, true, box BuiltinCombinedModuleLateLintPass::new()
 236         );
 237         store.register_late_pass(
 238             sess, false, true, false, box BuiltinCombinedLateLintPass::new()
 239         );
 240     }
 241
 242     add_lint_group!(sess,
 243                     "nonstandard_style",
 244                     NON_CAMEL_CASE_TYPES,
 245                     NON_SNAKE_CASE,
 246                     NON_UPPER_CASE_GLOBALS);
 247
 248     add_lint_group!(sess,
 249                     "unused",
 250                     UNUSED_IMPORTS,
 251                     UNUSED_VARIABLES,
 252                     UNUSED_ASSIGNMENTS,
 253                     DEAD_CODE,
 254                     UNUSED_MUT,
 255                     UNREACHABLE_CODE,
 256                     UNREACHABLE_PATTERNS,
 257                     UNUSED_MUST_USE,
 258                     UNUSED_UNSAFE,
 259                     PATH_STATEMENTS,
 260                     UNUSED_ATTRIBUTES,
 261                     UNUSED_MACROS,
 262                     UNUSED_ALLOCATION,
 263                     UNUSED_DOC_COMMENTS,
 264                     UNUSED_EXTERN_CRATES,
 265                     UNUSED_FEATURES,
 266                     UNUSED_LABELS,
 267                     UNUSED_PARENS);
 268
 269     add_lint_group!(sess,
 270                     "rust_2018_idioms",
 271                     BARE_TRAIT_OBJECTS,
 272                     UNUSED_EXTERN_CRATES,
 273                     ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
 274                     ELIDED_LIFETIMES_IN_PATHS,
 275                     EXPLICIT_OUTLIVES_REQUIREMENTS
 276
 277                     // FIXME(#52665, #47816) not always applicable and not all
 278                     // macros are ready for this yet.
 279                     // UNREACHABLE_PUB,
 280
 281                     // FIXME macro crates are not up for this yet, too much
 282                     // breakage is seen if we try to encourage this lint.
 283                     // MACRO_USE_EXTERN_CRATE,
 284                     );
 285
 286     add_lint_group!(sess,
 287                     "rustdoc",
 288                     INTRA_DOC_LINK_RESOLUTION_FAILURE,
 289                     MISSING_DOC_CODE_EXAMPLES,
 290                     PRIVATE_DOC_TESTS);
 291
 292     // Guidelines for creating a future incompatibility lint:
 293     //
 294     // - Create a lint defaulting to warn as normal, with ideally the same error
 295     //   message you would normally give
 296     // - Add a suitable reference, typically an RFC or tracking issue. Go ahead
 297     //   and include the full URL, sort items in ascending order of issue numbers.
 298     // - Later, change lint to error
 299     // - Eventually, remove lint
 300     store.register_future_incompatible(sess, vec![
 301         FutureIncompatibleInfo {
 302             id: LintId::of(PRIVATE_IN_PUBLIC),
 303             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
 304             edition: None,
 305         },
 306         FutureIncompatibleInfo {
 307             id: LintId::of(PUB_USE_OF_PRIVATE_EXTERN_CRATE),
 308             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
 309             edition: None,
 310         },
 311         FutureIncompatibleInfo {
 312             id: LintId::of(PATTERNS_IN_FNS_WITHOUT_BODY),
 313             reference: "issue #35203 <https://github.com/rust-lang/rust/issues/35203>",
 314             edition: None,
 315         },
 316         FutureIncompatibleInfo {
 317             id: LintId::of(DUPLICATE_MACRO_EXPORTS),
 318             reference: "issue #35896 <https://github.com/rust-lang/rust/issues/35896>",
 319             edition: Some(Edition::Edition2018),
 320         },
 321         FutureIncompatibleInfo {
 322             id: LintId::of(KEYWORD_IDENTS),
 323             reference: "issue #49716 <https://github.com/rust-lang/rust/issues/49716>",
 324             edition: Some(Edition::Edition2018),
 325         },
 326         FutureIncompatibleInfo {
 327             id: LintId::of(SAFE_EXTERN_STATICS),
 328             reference: "issue #36247 <https://github.com/rust-lang/rust/issues/36247>",
 329             edition: None,
 330         },
 331         FutureIncompatibleInfo {
 332             id: LintId::of(INVALID_TYPE_PARAM_DEFAULT),
 333             reference: "issue #36887 <https://github.com/rust-lang/rust/issues/36887>",
 334             edition: None,
 335         },
 336         FutureIncompatibleInfo {
 337             id: LintId::of(LEGACY_DIRECTORY_OWNERSHIP),
 338             reference: "issue #37872 <https://github.com/rust-lang/rust/issues/37872>",
 339             edition: None,
 340         },
 341         FutureIncompatibleInfo {
 342             id: LintId::of(LEGACY_CONSTRUCTOR_VISIBILITY),
 343             reference: "issue #39207 <https://github.com/rust-lang/rust/issues/39207>",
 344             edition: None,
 345         },
 346         FutureIncompatibleInfo {
 347             id: LintId::of(MISSING_FRAGMENT_SPECIFIER),
 348             reference: "issue #40107 <https://github.com/rust-lang/rust/issues/40107>",
 349             edition: None,
 350         },
 351         FutureIncompatibleInfo {
 352             id: LintId::of(ILLEGAL_FLOATING_POINT_LITERAL_PATTERN),
 353             reference: "issue #41620 <https://github.com/rust-lang/rust/issues/41620>",
 354             edition: None,
 355         },
 356         FutureIncompatibleInfo {
 357             id: LintId::of(ANONYMOUS_PARAMETERS),
 358             reference: "issue #41686 <https://github.com/rust-lang/rust/issues/41686>",
 359             edition: Some(Edition::Edition2018),
 360         },
 361         FutureIncompatibleInfo {
 362             id: LintId::of(PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES),
 363             reference: "issue #42238 <https://github.com/rust-lang/rust/issues/42238>",
 364             edition: None,
 365         },
 366         FutureIncompatibleInfo {
 367             id: LintId::of(LATE_BOUND_LIFETIME_ARGUMENTS),
 368             reference: "issue #42868 <https://github.com/rust-lang/rust/issues/42868>",
 369             edition: None,
 370         },
 371         FutureIncompatibleInfo {
 372             id: LintId::of(SAFE_PACKED_BORROWS),
 373             reference: "issue #46043 <https://github.com/rust-lang/rust/issues/46043>",
 374             edition: None,
 375         },
 376         FutureIncompatibleInfo {
 377             id: LintId::of(ORDER_DEPENDENT_TRAIT_OBJECTS),
 378             reference: "issue #56484 <https://github.com/rust-lang/rust/issues/56484>",
 379             edition: None,
 380         },
 381         FutureIncompatibleInfo {
 382             id: LintId::of(TYVAR_BEHIND_RAW_POINTER),
 383             reference: "issue #46906 <https://github.com/rust-lang/rust/issues/46906>",
 384             edition: Some(Edition::Edition2018),
 385         },
 386         FutureIncompatibleInfo {
 387             id: LintId::of(UNSTABLE_NAME_COLLISIONS),
 388             reference: "issue #48919 <https://github.com/rust-lang/rust/issues/48919>",
 389             edition: None,
 390             // Note: this item represents future incompatibility of all unstable functions in the
 391             //       standard library, and thus should never be removed or changed to an error.
 392         },
 393         FutureIncompatibleInfo {
 394             id: LintId::of(ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE),
 395             reference: "issue #53130 <https://github.com/rust-lang/rust/issues/53130>",
 396             edition: Some(Edition::Edition2018),
 397         },
 398         FutureIncompatibleInfo {
 399             id: LintId::of(WHERE_CLAUSES_OBJECT_SAFETY),
 400             reference: "issue #51443 <https://github.com/rust-lang/rust/issues/51443>",
 401             edition: None,
 402         },
 403         FutureIncompatibleInfo {
 404             id: LintId::of(PROC_MACRO_DERIVE_RESOLUTION_FALLBACK),
 405             reference: "issue #50504 <https://github.com/rust-lang/rust/issues/50504>",
 406             edition: None,
 407         },
 408         FutureIncompatibleInfo {
 409             id: LintId::of(MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS),
 410             reference: "issue #52234 <https://github.com/rust-lang/rust/issues/52234>",
 411             edition: None,
 412         },
 413         FutureIncompatibleInfo {
 414             id: LintId::of(ILL_FORMED_ATTRIBUTE_INPUT),
 415             reference: "issue #57571 <https://github.com/rust-lang/rust/issues/57571>",
 416             edition: None,
 417         },
 418         FutureIncompatibleInfo {
 419             id: LintId::of(AMBIGUOUS_ASSOCIATED_ITEMS),
 420             reference: "issue #57644 <https://github.com/rust-lang/rust/issues/57644>",
 421             edition: None,
 422         },
 423         FutureIncompatibleInfo {
 424             id: LintId::of(NESTED_IMPL_TRAIT),
 425             reference: "issue #59014 <https://github.com/rust-lang/rust/issues/59014>",
 426             edition: None,
 427         },
 428         FutureIncompatibleInfo {
 429             id: LintId::of(MUTABLE_BORROW_RESERVATION_CONFLICT),
 430             reference: "issue #59159 <https://github.com/rust-lang/rust/issues/59159>",
 431             edition: None,
 432         },
 433         FutureIncompatibleInfo {
 434             id: LintId::of(INDIRECT_STRUCTURAL_MATCH),
 435             reference: "issue #62411 <https://github.com/rust-lang/rust/issues/62411>",
 436             edition: None,
 437         }
 438         ]);
 439
 440     // Register renamed and removed lints.
 441     store.register_renamed("single_use_lifetime", "single_use_lifetimes");
 442     store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
 443     store.register_renamed("bare_trait_object", "bare_trait_objects");
 444     store.register_renamed("unstable_name_collision", "unstable_name_collisions");
 445     store.register_renamed("unused_doc_comment", "unused_doc_comments");
 446     store.register_renamed("async_idents", "keyword_idents");
 447     store.register_removed("unknown_features", "replaced by an error");
 448     store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
 449     store.register_removed("negate_unsigned", "cast a signed value instead");
 450     store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
 451     // Register lint group aliases.
 452     store.register_group_alias("nonstandard_style", "bad_style");
 453     // This was renamed to `raw_pointer_derive`, which was then removed,
 454     // so it is also considered removed.
 455     store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
 456     store.register_removed("drop_with_repr_extern", "drop flags have been removed");
 457     store.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
 458     store.register_removed("deprecated_attr", "use `deprecated` instead");
 459     store.register_removed("transmute_from_fn_item_types",
 460         "always cast functions before transmuting them");
 461     store.register_removed("hr_lifetime_in_assoc_type",
 462         "converted into hard error, see https://github.com/rust-lang/rust/issues/33685");
 463     store.register_removed("inaccessible_extern_crate",
 464         "converted into hard error, see https://github.com/rust-lang/rust/issues/36886");
 465     store.register_removed("super_or_self_in_global_path",
 466         "converted into hard error, see https://github.com/rust-lang/rust/issues/36888");
 467     store.register_removed("overlapping_inherent_impls",
 468         "converted into hard error, see https://github.com/rust-lang/rust/issues/36889");
 469     store.register_removed("illegal_floating_point_constant_pattern",
 470         "converted into hard error, see https://github.com/rust-lang/rust/issues/36890");
 471     store.register_removed("illegal_struct_or_enum_constant_pattern",
 472         "converted into hard error, see https://github.com/rust-lang/rust/issues/36891");
 473     store.register_removed("lifetime_underscore",
 474         "converted into hard error, see https://github.com/rust-lang/rust/issues/36892");
 475     store.register_removed("extra_requirement_in_impl",
 476         "converted into hard error, see https://github.com/rust-lang/rust/issues/37166");
 477     store.register_removed("legacy_imports",
 478         "converted into hard error, see https://github.com/rust-lang/rust/issues/38260");
 479     store.register_removed("coerce_never",
 480         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950");
 481     store.register_removed("resolve_trait_on_defaulted_unit",
 482         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950");
 483     store.register_removed("private_no_mangle_fns",
 484         "no longer a warning, `#[no_mangle]` functions always exported");
 485     store.register_removed("private_no_mangle_statics",
 486         "no longer a warning, `#[no_mangle]` statics always exported");
 487     store.register_removed("bad_repr",
 488         "replaced with a generic attribute input check");
 489     store.register_removed("duplicate_matcher_binding_name",
 490         "converted into hard error, see https://github.com/rust-lang/rust/issues/57742");
 491     store.register_removed("incoherent_fundamental_impls",
 492         "converted into hard error, see https://github.com/rust-lang/rust/issues/46205");
 493 }
 494
 495 pub fn register_internals(store: &mut lint::LintStore, sess: Option<&Session>) {
 496     store.register_early_pass(sess, false, false, box DefaultHashTypes::new());
 497     store.register_early_pass(sess, false, false, box LintPassImpl);
 498     store.register_late_pass(sess, false, false, false, box TyTyKind);
 499     store.register_group(
 500         sess,
 501         false,
 502         "rustc::internal",
 503         None,
 504         vec![
 505             LintId::of(DEFAULT_HASH_TYPES),
 506             LintId::of(USAGE_OF_TY_TYKIND),
 507             LintId::of(LINT_PASS_IMPL_WITHOUT_MACRO),
 508             LintId::of(TY_PASS_BY_REFERENCE),
 509             LintId::of(USAGE_OF_QUALIFIED_TY),
 510         ],
 511     );
 512 }