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
  14 #![cfg_attr(test, feature(test))]
  15 #![feature(box_patterns)]
  16 #![feature(box_syntax)]
  17 #![feature(nll)]
  18
  19 #![recursion_limit="256"]
  20
  21 #[macro_use]
  22 extern crate rustc;
  23
  24 mod error_codes;
  25 mod nonstandard_style;
  26 mod redundant_semicolon;
  27 pub mod builtin;
  28 mod types;
  29 mod unused;
  30 mod non_ascii_idents;
  31
  32 use rustc::lint;
  33 use rustc::lint::{EarlyContext, LateContext, LateLintPass, EarlyLintPass, LintPass, LintArray};
  34 use rustc::lint::builtin::{
  35     BARE_TRAIT_OBJECTS,
  36     ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  37     ELIDED_LIFETIMES_IN_PATHS,
  38     EXPLICIT_OUTLIVES_REQUIREMENTS,
  39     INTRA_DOC_LINK_RESOLUTION_FAILURE,
  40     MISSING_DOC_CODE_EXAMPLES,
  41     PRIVATE_DOC_TESTS,
  42     parser::ILL_FORMED_ATTRIBUTE_INPUT,
  43 };
  44 use rustc::session;
  45 use rustc::hir;
  46 use rustc::hir::def_id::DefId;
  47 use rustc::ty::query::Providers;
  48 use rustc::ty::TyCtxt;
  49
  50 use syntax::ast;
  51 use syntax::edition::Edition;
  52 use syntax_pos::Span;
  53
  54 use session::Session;
  55 use lint::LintId;
  56 use lint::FutureIncompatibleInfo;
  57
  58 use redundant_semicolon::*;
  59 use nonstandard_style::*;
  60 use builtin::*;
  61 use types::*;
  62 use unused::*;
  63 use non_ascii_idents::*;
  64 use rustc::lint::internal::*;
  65
  66 /// Useful for other parts of the compiler.
  67 pub use builtin::SoftLints;
  68
  69 pub fn provide(providers: &mut Providers<'_>) {
  70     *providers = Providers {
  71         lint_mod,
  72         ..*providers
  73     };
  74 }
  75
  76 fn lint_mod(tcx: TyCtxt<'_>, module_def_id: DefId) {
  77     lint::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, [
  83             KeywordIdents: KeywordIdents,
  84             UnusedDocComment: UnusedDocComment,
  85         ]);
  86     )
  87 }
  88
  89 macro_rules! early_lint_passes {
  90     ($macro:path, $args:tt) => (
  91         $macro!($args, [
  92             UnusedParens: UnusedParens,
  93             UnusedImportBraces: UnusedImportBraces,
  94             UnsafeCode: UnsafeCode,
  95             AnonymousParameters: AnonymousParameters,
  96             EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns::default(),
  97             NonCamelCaseTypes: NonCamelCaseTypes,
  98             DeprecatedAttr: DeprecatedAttr::new(),
  99             WhileTrue: WhileTrue,
 100             NonAsciiIdents: NonAsciiIdents,
 101             IncompleteFeatures: IncompleteFeatures,
 102             RedundantSemicolon: RedundantSemicolon,
 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             TypeAliasBounds: TypeAliasBounds,
 168
 169             TrivialConstraints: TrivialConstraints,
 170             TypeLimits: TypeLimits::new(),
 171
 172             NonSnakeCase: NonSnakeCase,
 173             InvalidNoMangleItems: InvalidNoMangleItems,
 174
 175             // Depends on access levels
 176             UnreachablePub: UnreachablePub,
 177
 178             ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
 179             InvalidValue: InvalidValue,
 180         ]);
 181     )
 182 }
 183
 184 macro_rules! declare_combined_late_pass {
 185     ([$v:vis $name:ident], $passes:tt) => (
 186         late_lint_methods!(declare_combined_late_lint_pass, [$v $name, $passes], ['tcx]);
 187     )
 188 }
 189
 190 // FIXME: Make a separate lint type which do not require typeck tables
 191 late_lint_passes!(declare_combined_late_pass, [pub BuiltinCombinedLateLintPass]);
 192
 193 late_lint_mod_passes!(declare_combined_late_pass, [BuiltinCombinedModuleLateLintPass]);
 194
 195 /// Tell the `LintStore` about all the built-in lints (the ones
 196 /// defined in this crate and the ones defined in
 197 /// `rustc::lint::builtin`).
 198 pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
 199     macro_rules! add_lint_group {
 200         ($sess:ident, $name:expr, $($lint:ident),*) => (
 201             store.register_group($sess, false, $name, None, vec![$(LintId::of($lint)),*]);
 202         )
 203     }
 204
 205     macro_rules! register_pass {
 206         ($method:ident, $constructor:expr, [$($args:expr),*]) => (
 207             store.$method(sess, false, false, $($args,)* box $constructor);
 208         )
 209     }
 210
 211     macro_rules! register_passes {
 212         ([$method:ident, $args:tt], [$($passes:ident: $constructor:expr,)*]) => (
 213             $(
 214                 register_pass!($method, $constructor, $args);
 215             )*
 216         )
 217     }
 218
 219     if sess.map(|sess| sess.opts.debugging_opts.no_interleave_lints).unwrap_or(false) {
 220         pre_expansion_lint_passes!(register_passes, [register_pre_expansion_pass, []]);
 221         early_lint_passes!(register_passes, [register_early_pass, []]);
 222         late_lint_passes!(register_passes, [register_late_pass, [false]]);
 223         late_lint_mod_passes!(register_passes, [register_late_pass, [true]]);
 224     } else {
 225         store.register_pre_expansion_pass(
 226             sess,
 227             false,
 228             true,
 229             box BuiltinCombinedPreExpansionLintPass::new()
 230         );
 231         store.register_early_pass(sess, false, true, box BuiltinCombinedEarlyLintPass::new());
 232         store.register_late_pass(
 233             sess, false, true, true, box BuiltinCombinedModuleLateLintPass::new()
 234         );
 235         store.register_late_pass(
 236             sess, false, true, false, box BuiltinCombinedLateLintPass::new()
 237         );
 238     }
 239
 240     add_lint_group!(sess,
 241                     "nonstandard_style",
 242                     NON_CAMEL_CASE_TYPES,
 243                     NON_SNAKE_CASE,
 244                     NON_UPPER_CASE_GLOBALS);
 245
 246     add_lint_group!(sess,
 247                     "unused",
 248                     UNUSED_IMPORTS,
 249                     UNUSED_VARIABLES,
 250                     UNUSED_ASSIGNMENTS,
 251                     DEAD_CODE,
 252                     UNUSED_MUT,
 253                     UNREACHABLE_CODE,
 254                     UNREACHABLE_PATTERNS,
 255                     OVERLAPPING_PATTERNS,
 256                     UNUSED_MUST_USE,
 257                     UNUSED_UNSAFE,
 258                     PATH_STATEMENTS,
 259                     UNUSED_ATTRIBUTES,
 260                     UNUSED_MACROS,
 261                     UNUSED_ALLOCATION,
 262                     UNUSED_DOC_COMMENTS,
 263                     UNUSED_EXTERN_CRATES,
 264                     UNUSED_FEATURES,
 265                     UNUSED_LABELS,
 266                     UNUSED_PARENS);
 267
 268     add_lint_group!(sess,
 269                     "rust_2018_idioms",
 270                     BARE_TRAIT_OBJECTS,
 271                     UNUSED_EXTERN_CRATES,
 272                     ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
 273                     ELIDED_LIFETIMES_IN_PATHS,
 274                     EXPLICIT_OUTLIVES_REQUIREMENTS
 275
 276                     // FIXME(#52665, #47816) not always applicable and not all
 277                     // macros are ready for this yet.
 278                     // UNREACHABLE_PUB,
 279
 280                     // FIXME macro crates are not up for this yet, too much
 281                     // breakage is seen if we try to encourage this lint.
 282                     // MACRO_USE_EXTERN_CRATE,
 283                     );
 284
 285     add_lint_group!(sess,
 286                     "rustdoc",
 287                     INTRA_DOC_LINK_RESOLUTION_FAILURE,
 288                     MISSING_DOC_CODE_EXAMPLES,
 289                     PRIVATE_DOC_TESTS);
 290
 291     // Guidelines for creating a future incompatibility lint:
 292     //
 293     // - Create a lint defaulting to warn as normal, with ideally the same error
 294     //   message you would normally give
 295     // - Add a suitable reference, typically an RFC or tracking issue. Go ahead
 296     //   and include the full URL, sort items in ascending order of issue numbers.
 297     // - Later, change lint to error
 298     // - Eventually, remove lint
 299     store.register_future_incompatible(sess, vec![
 300         FutureIncompatibleInfo {
 301             id: LintId::of(PRIVATE_IN_PUBLIC),
 302             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
 303             edition: None,
 304         },
 305         FutureIncompatibleInfo {
 306             id: LintId::of(PUB_USE_OF_PRIVATE_EXTERN_CRATE),
 307             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
 308             edition: None,
 309         },
 310         FutureIncompatibleInfo {
 311             id: LintId::of(PATTERNS_IN_FNS_WITHOUT_BODY),
 312             reference: "issue #35203 <https://github.com/rust-lang/rust/issues/35203>",
 313             edition: None,
 314         },
 315         FutureIncompatibleInfo {
 316             id: LintId::of(DUPLICATE_MACRO_EXPORTS),
 317             reference: "issue #35896 <https://github.com/rust-lang/rust/issues/35896>",
 318             edition: Some(Edition::Edition2018),
 319         },
 320         FutureIncompatibleInfo {
 321             id: LintId::of(KEYWORD_IDENTS),
 322             reference: "issue #49716 <https://github.com/rust-lang/rust/issues/49716>",
 323             edition: Some(Edition::Edition2018),
 324         },
 325         FutureIncompatibleInfo {
 326             id: LintId::of(SAFE_EXTERN_STATICS),
 327             reference: "issue #36247 <https://github.com/rust-lang/rust/issues/36247>",
 328             edition: None,
 329         },
 330         FutureIncompatibleInfo {
 331             id: LintId::of(INVALID_TYPE_PARAM_DEFAULT),
 332             reference: "issue #36887 <https://github.com/rust-lang/rust/issues/36887>",
 333             edition: None,
 334         },
 335         FutureIncompatibleInfo {
 336             id: LintId::of(LEGACY_DIRECTORY_OWNERSHIP),
 337             reference: "issue #37872 <https://github.com/rust-lang/rust/issues/37872>",
 338             edition: None,
 339         },
 340         FutureIncompatibleInfo {
 341             id: LintId::of(LEGACY_CONSTRUCTOR_VISIBILITY),
 342             reference: "issue #39207 <https://github.com/rust-lang/rust/issues/39207>",
 343             edition: None,
 344         },
 345         FutureIncompatibleInfo {
 346             id: LintId::of(MISSING_FRAGMENT_SPECIFIER),
 347             reference: "issue #40107 <https://github.com/rust-lang/rust/issues/40107>",
 348             edition: None,
 349         },
 350         FutureIncompatibleInfo {
 351             id: LintId::of(ILLEGAL_FLOATING_POINT_LITERAL_PATTERN),
 352             reference: "issue #41620 <https://github.com/rust-lang/rust/issues/41620>",
 353             edition: None,
 354         },
 355         FutureIncompatibleInfo {
 356             id: LintId::of(ANONYMOUS_PARAMETERS),
 357             reference: "issue #41686 <https://github.com/rust-lang/rust/issues/41686>",
 358             edition: Some(Edition::Edition2018),
 359         },
 360         FutureIncompatibleInfo {
 361             id: LintId::of(PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES),
 362             reference: "issue #42238 <https://github.com/rust-lang/rust/issues/42238>",
 363             edition: None,
 364         },
 365         FutureIncompatibleInfo {
 366             id: LintId::of(LATE_BOUND_LIFETIME_ARGUMENTS),
 367             reference: "issue #42868 <https://github.com/rust-lang/rust/issues/42868>",
 368             edition: None,
 369         },
 370         FutureIncompatibleInfo {
 371             id: LintId::of(SAFE_PACKED_BORROWS),
 372             reference: "issue #46043 <https://github.com/rust-lang/rust/issues/46043>",
 373             edition: None,
 374         },
 375         FutureIncompatibleInfo {
 376             id: LintId::of(ORDER_DEPENDENT_TRAIT_OBJECTS),
 377             reference: "issue #56484 <https://github.com/rust-lang/rust/issues/56484>",
 378             edition: None,
 379         },
 380         FutureIncompatibleInfo {
 381             id: LintId::of(TYVAR_BEHIND_RAW_POINTER),
 382             reference: "issue #46906 <https://github.com/rust-lang/rust/issues/46906>",
 383             edition: Some(Edition::Edition2018),
 384         },
 385         FutureIncompatibleInfo {
 386             id: LintId::of(UNSTABLE_NAME_COLLISIONS),
 387             reference: "issue #48919 <https://github.com/rust-lang/rust/issues/48919>",
 388             edition: None,
 389             // Note: this item represents future incompatibility of all unstable functions in the
 390             //       standard library, and thus should never be removed or changed to an error.
 391         },
 392         FutureIncompatibleInfo {
 393             id: LintId::of(ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE),
 394             reference: "issue #53130 <https://github.com/rust-lang/rust/issues/53130>",
 395             edition: Some(Edition::Edition2018),
 396         },
 397         FutureIncompatibleInfo {
 398             id: LintId::of(WHERE_CLAUSES_OBJECT_SAFETY),
 399             reference: "issue #51443 <https://github.com/rust-lang/rust/issues/51443>",
 400             edition: None,
 401         },
 402         FutureIncompatibleInfo {
 403             id: LintId::of(PROC_MACRO_DERIVE_RESOLUTION_FALLBACK),
 404             reference: "issue #50504 <https://github.com/rust-lang/rust/issues/50504>",
 405             edition: None,
 406         },
 407         FutureIncompatibleInfo {
 408             id: LintId::of(MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS),
 409             reference: "issue #52234 <https://github.com/rust-lang/rust/issues/52234>",
 410             edition: None,
 411         },
 412         FutureIncompatibleInfo {
 413             id: LintId::of(ILL_FORMED_ATTRIBUTE_INPUT),
 414             reference: "issue #57571 <https://github.com/rust-lang/rust/issues/57571>",
 415             edition: None,
 416         },
 417         FutureIncompatibleInfo {
 418             id: LintId::of(AMBIGUOUS_ASSOCIATED_ITEMS),
 419             reference: "issue #57644 <https://github.com/rust-lang/rust/issues/57644>",
 420             edition: None,
 421         },
 422         FutureIncompatibleInfo {
 423             id: LintId::of(NESTED_IMPL_TRAIT),
 424             reference: "issue #59014 <https://github.com/rust-lang/rust/issues/59014>",
 425             edition: None,
 426         },
 427         FutureIncompatibleInfo {
 428             id: LintId::of(MUTABLE_BORROW_RESERVATION_CONFLICT),
 429             reference: "issue #59159 <https://github.com/rust-lang/rust/issues/59159>",
 430             edition: None,
 431         },
 432         FutureIncompatibleInfo {
 433             id: LintId::of(INDIRECT_STRUCTURAL_MATCH),
 434             reference: "issue #62411 <https://github.com/rust-lang/rust/issues/62411>",
 435             edition: None,
 436         },
 437         FutureIncompatibleInfo {
 438             id: LintId::of(SOFT_UNSTABLE),
 439             reference: "issue #64266 <https://github.com/rust-lang/rust/issues/64266>",
 440             edition: None,
 441         },
 442         ]);
 443
 444     // Register renamed and removed lints.
 445     store.register_renamed("single_use_lifetime", "single_use_lifetimes");
 446     store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
 447     store.register_renamed("bare_trait_object", "bare_trait_objects");
 448     store.register_renamed("unstable_name_collision", "unstable_name_collisions");
 449     store.register_renamed("unused_doc_comment", "unused_doc_comments");
 450     store.register_renamed("async_idents", "keyword_idents");
 451     store.register_removed("unknown_features", "replaced by an error");
 452     store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
 453     store.register_removed("negate_unsigned", "cast a signed value instead");
 454     store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
 455     // Register lint group aliases.
 456     store.register_group_alias("nonstandard_style", "bad_style");
 457     // This was renamed to `raw_pointer_derive`, which was then removed,
 458     // so it is also considered removed.
 459     store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
 460     store.register_removed("drop_with_repr_extern", "drop flags have been removed");
 461     store.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
 462     store.register_removed("deprecated_attr", "use `deprecated` instead");
 463     store.register_removed("transmute_from_fn_item_types",
 464         "always cast functions before transmuting them");
 465     store.register_removed("hr_lifetime_in_assoc_type",
 466         "converted into hard error, see https://github.com/rust-lang/rust/issues/33685");
 467     store.register_removed("inaccessible_extern_crate",
 468         "converted into hard error, see https://github.com/rust-lang/rust/issues/36886");
 469     store.register_removed("super_or_self_in_global_path",
 470         "converted into hard error, see https://github.com/rust-lang/rust/issues/36888");
 471     store.register_removed("overlapping_inherent_impls",
 472         "converted into hard error, see https://github.com/rust-lang/rust/issues/36889");
 473     store.register_removed("illegal_floating_point_constant_pattern",
 474         "converted into hard error, see https://github.com/rust-lang/rust/issues/36890");
 475     store.register_removed("illegal_struct_or_enum_constant_pattern",
 476         "converted into hard error, see https://github.com/rust-lang/rust/issues/36891");
 477     store.register_removed("lifetime_underscore",
 478         "converted into hard error, see https://github.com/rust-lang/rust/issues/36892");
 479     store.register_removed("extra_requirement_in_impl",
 480         "converted into hard error, see https://github.com/rust-lang/rust/issues/37166");
 481     store.register_removed("legacy_imports",
 482         "converted into hard error, see https://github.com/rust-lang/rust/issues/38260");
 483     store.register_removed("coerce_never",
 484         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950");
 485     store.register_removed("resolve_trait_on_defaulted_unit",
 486         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950");
 487     store.register_removed("private_no_mangle_fns",
 488         "no longer a warning, `#[no_mangle]` functions always exported");
 489     store.register_removed("private_no_mangle_statics",
 490         "no longer a warning, `#[no_mangle]` statics always exported");
 491     store.register_removed("bad_repr",
 492         "replaced with a generic attribute input check");
 493     store.register_removed("duplicate_matcher_binding_name",
 494         "converted into hard error, see https://github.com/rust-lang/rust/issues/57742");
 495     store.register_removed("incoherent_fundamental_impls",
 496         "converted into hard error, see https://github.com/rust-lang/rust/issues/46205");
 497 }
 498
 499 pub fn register_internals(store: &mut lint::LintStore, sess: Option<&Session>) {
 500     store.register_early_pass(sess, false, false, box DefaultHashTypes::new());
 501     store.register_early_pass(sess, false, false, box LintPassImpl);
 502     store.register_late_pass(sess, false, false, false, box TyTyKind);
 503     store.register_group(
 504         sess,
 505         false,
 506         "rustc::internal",
 507         None,
 508         vec![
 509             LintId::of(DEFAULT_HASH_TYPES),
 510             LintId::of(USAGE_OF_TY_TYKIND),
 511             LintId::of(LINT_PASS_IMPL_WITHOUT_MACRO),
 512             LintId::of(TY_PASS_BY_REFERENCE),
 513             LintId::of(USAGE_OF_QUALIFIED_TY),
 514         ],
 515     );
 516 }