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
  24 #[macro_use]
  25 extern crate rustc;
  26
  27 mod diagnostics;
  28 mod nonstandard_style;
  29 pub mod builtin;
  30 mod types;
  31 mod unused;
  32
  33 use rustc::lint;
  34 use rustc::lint::{EarlyContext, LateContext, LateLintPass, EarlyLintPass, LintPass, LintArray};
  35 use rustc::lint::builtin::{
  36     BARE_TRAIT_OBJECTS,
  37     ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  38     ELIDED_LIFETIMES_IN_PATHS,
  39     EXPLICIT_OUTLIVES_REQUIREMENTS,
  40     INTRA_DOC_LINK_RESOLUTION_FAILURE,
  41     MISSING_DOC_CODE_EXAMPLES,
  42     PRIVATE_DOC_TESTS,
  43     parser::QUESTION_MARK_MACRO_SEP,
  44     parser::ILL_FORMED_ATTRIBUTE_INPUT,
  45 };
  46 use rustc::session;
  47 use rustc::hir;
  48 use rustc::hir::def_id::DefId;
  49 use rustc::ty::query::Providers;
  50 use rustc::ty::TyCtxt;
  51
  52 use syntax::ast;
  53 use syntax::edition::Edition;
  54 use syntax_pos::Span;
  55
  56 use session::Session;
  57 use lint::LintId;
  58 use lint::FutureIncompatibleInfo;
  59
  60 use nonstandard_style::*;
  61 use builtin::*;
  62 use types::*;
  63 use unused::*;
  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>(tcx: TyCtxt<'_, 'tcx, 'tcx>, 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,
  97             NonCamelCaseTypes: NonCamelCaseTypes,
  98             DeprecatedAttr: DeprecatedAttr::new(),
  99         ]);
 100     )
 101 }
 102
 103 macro_rules! declare_combined_early_pass {
 104     ([$name:ident], $passes:tt) => (
 105         early_lint_methods!(declare_combined_early_lint_pass, [pub $name, $passes]);
 106     )
 107 }
 108
 109 pre_expansion_lint_passes!(declare_combined_early_pass, [BuiltinCombinedPreExpansionLintPass]);
 110 early_lint_passes!(declare_combined_early_pass, [BuiltinCombinedEarlyLintPass]);
 111
 112 macro_rules! late_lint_passes {
 113     ($macro:path, $args:tt) => (
 114         $macro!($args, [
 115             // FIXME: Look into regression when this is used as a module lint
 116             // May Depend on constants elsewhere
 117             UnusedBrokenConst: UnusedBrokenConst,
 118
 119             // Uses attr::is_used which is untracked, can't be an incremental module pass.
 120             UnusedAttributes: UnusedAttributes,
 121
 122             // Needs to run after UnusedAttributes as it marks all `feature` attributes as used.
 123             UnstableFeatures: UnstableFeatures,
 124
 125             // Tracks state across modules
 126             UnnameableTestItems: UnnameableTestItems::new(),
 127
 128             // Tracks attributes of parents
 129             MissingDoc: MissingDoc::new(),
 130
 131             // Depends on access levels
 132             // FIXME: Turn the computation of types which implement Debug into a query
 133             // and change this to a module lint pass
 134             MissingDebugImplementations: MissingDebugImplementations::new(),
 135         ]);
 136     )
 137 }
 138
 139 macro_rules! late_lint_mod_passes {
 140     ($macro:path, $args:tt) => (
 141         $macro!($args, [
 142             HardwiredLints: HardwiredLints,
 143             WhileTrue: WhileTrue,
 144             ImproperCTypes: ImproperCTypes,
 145             VariantSizeDifferences: VariantSizeDifferences,
 146             BoxPointers: BoxPointers,
 147             PathStatements: PathStatements,
 148
 149             // Depends on referenced function signatures in expressions
 150             UnusedResults: UnusedResults,
 151
 152             NonUpperCaseGlobals: NonUpperCaseGlobals,
 153             NonShorthandFieldPatterns: NonShorthandFieldPatterns,
 154             UnusedAllocation: UnusedAllocation,
 155
 156             // Depends on types used in type definitions
 157             MissingCopyImplementations: MissingCopyImplementations,
 158
 159             PluginAsLibrary: PluginAsLibrary,
 160
 161             // Depends on referenced function signatures in expressions
 162             MutableTransmutes: MutableTransmutes,
 163
 164             // Depends on types of fields, checks if they implement Drop
 165             UnionsWithDropFields: UnionsWithDropFields,
 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         ]);
 180     )
 181 }
 182
 183 macro_rules! declare_combined_late_pass {
 184     ([$v:vis $name:ident], $passes:tt) => (
 185         late_lint_methods!(declare_combined_late_lint_pass, [$v $name, $passes], ['tcx]);
 186     )
 187 }
 188
 189 // FIXME: Make a separate lint type which do not require typeck tables
 190 late_lint_passes!(declare_combined_late_pass, [pub BuiltinCombinedLateLintPass]);
 191
 192 late_lint_mod_passes!(declare_combined_late_pass, [BuiltinCombinedModuleLateLintPass]);
 193
 194 /// Tell the `LintStore` about all the built-in lints (the ones
 195 /// defined in this crate and the ones defined in
 196 /// `rustc::lint::builtin`).
 197 pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
 198     macro_rules! add_lint_group {
 199         ($sess:ident, $name:expr, $($lint:ident),*) => (
 200             store.register_group($sess, false, $name, None, vec![$(LintId::of($lint)),*]);
 201         )
 202     }
 203
 204     macro_rules! register_pass {
 205         ($method:ident, $constructor:expr, [$($args:expr),*]) => (
 206             store.$method(sess, false, false, $($args,)* box $constructor);
 207         )
 208     }
 209
 210     macro_rules! register_passes {
 211         ([$method:ident, $args:tt], [$($passes:ident: $constructor:expr,)*]) => (
 212             $(
 213                 register_pass!($method, $constructor, $args);
 214             )*
 215         )
 216     }
 217
 218     if sess.map(|sess| sess.opts.debugging_opts.no_interleave_lints).unwrap_or(false) {
 219         pre_expansion_lint_passes!(register_passes, [register_pre_expansion_pass, []]);
 220         early_lint_passes!(register_passes, [register_early_pass, []]);
 221         late_lint_passes!(register_passes, [register_late_pass, [false]]);
 222         late_lint_mod_passes!(register_passes, [register_late_pass, [true]]);
 223     } else {
 224         store.register_pre_expansion_pass(
 225             sess,
 226             false,
 227             true,
 228             box BuiltinCombinedPreExpansionLintPass::new()
 229         );
 230         store.register_early_pass(sess, false, true, box BuiltinCombinedEarlyLintPass::new());
 231         store.register_late_pass(
 232             sess, false, true, true, box BuiltinCombinedModuleLateLintPass::new()
 233         );
 234         store.register_late_pass(
 235             sess, false, true, false, box BuiltinCombinedLateLintPass::new()
 236         );
 237     }
 238
 239     add_lint_group!(sess,
 240                     "nonstandard_style",
 241                     NON_CAMEL_CASE_TYPES,
 242                     NON_SNAKE_CASE,
 243                     NON_UPPER_CASE_GLOBALS);
 244
 245     add_lint_group!(sess,
 246                     "unused",
 247                     UNUSED_IMPORTS,
 248                     UNUSED_VARIABLES,
 249                     UNUSED_ASSIGNMENTS,
 250                     DEAD_CODE,
 251                     UNUSED_MUT,
 252                     UNREACHABLE_CODE,
 253                     UNREACHABLE_PATTERNS,
 254                     UNUSED_MUST_USE,
 255                     UNUSED_UNSAFE,
 256                     PATH_STATEMENTS,
 257                     UNUSED_ATTRIBUTES,
 258                     UNUSED_MACROS,
 259                     UNUSED_ALLOCATION,
 260                     UNUSED_DOC_COMMENTS,
 261                     UNUSED_EXTERN_CRATES,
 262                     UNUSED_FEATURES,
 263                     UNUSED_LABELS,
 264                     UNUSED_PARENS);
 265
 266     add_lint_group!(sess,
 267                     "rust_2018_idioms",
 268                     BARE_TRAIT_OBJECTS,
 269                     UNUSED_EXTERN_CRATES,
 270                     ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
 271                     ELIDED_LIFETIMES_IN_PATHS,
 272                     EXPLICIT_OUTLIVES_REQUIREMENTS
 273
 274                     // FIXME(#52665, #47816) not always applicable and not all
 275                     // macros are ready for this yet.
 276                     // UNREACHABLE_PUB,
 277
 278                     // FIXME macro crates are not up for this yet, too much
 279                     // breakage is seen if we try to encourage this lint.
 280                     // MACRO_USE_EXTERN_CRATE,
 281                     );
 282
 283     add_lint_group!(sess,
 284                     "rustdoc",
 285                     INTRA_DOC_LINK_RESOLUTION_FAILURE,
 286                     MISSING_DOC_CODE_EXAMPLES,
 287                     PRIVATE_DOC_TESTS);
 288
 289     // Guidelines for creating a future incompatibility lint:
 290     //
 291     // - Create a lint defaulting to warn as normal, with ideally the same error
 292     //   message you would normally give
 293     // - Add a suitable reference, typically an RFC or tracking issue. Go ahead
 294     //   and include the full URL, sort items in ascending order of issue numbers.
 295     // - Later, change lint to error
 296     // - Eventually, remove lint
 297     store.register_future_incompatible(sess, vec![
 298         FutureIncompatibleInfo {
 299             id: LintId::of(PRIVATE_IN_PUBLIC),
 300             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
 301             edition: None,
 302         },
 303         FutureIncompatibleInfo {
 304             id: LintId::of(PUB_USE_OF_PRIVATE_EXTERN_CRATE),
 305             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
 306             edition: None,
 307         },
 308         FutureIncompatibleInfo {
 309             id: LintId::of(PATTERNS_IN_FNS_WITHOUT_BODY),
 310             reference: "issue #35203 <https://github.com/rust-lang/rust/issues/35203>",
 311             edition: None,
 312         },
 313         FutureIncompatibleInfo {
 314             id: LintId::of(DUPLICATE_MACRO_EXPORTS),
 315             reference: "issue #35896 <https://github.com/rust-lang/rust/issues/35896>",
 316             edition: Some(Edition::Edition2018),
 317         },
 318         FutureIncompatibleInfo {
 319             id: LintId::of(KEYWORD_IDENTS),
 320             reference: "issue #49716 <https://github.com/rust-lang/rust/issues/49716>",
 321             edition: Some(Edition::Edition2018),
 322         },
 323         FutureIncompatibleInfo {
 324             id: LintId::of(SAFE_EXTERN_STATICS),
 325             reference: "issue #36247 <https://github.com/rust-lang/rust/issues/36247>",
 326             edition: None,
 327         },
 328         FutureIncompatibleInfo {
 329             id: LintId::of(INVALID_TYPE_PARAM_DEFAULT),
 330             reference: "issue #36887 <https://github.com/rust-lang/rust/issues/36887>",
 331             edition: None,
 332         },
 333         FutureIncompatibleInfo {
 334             id: LintId::of(LEGACY_DIRECTORY_OWNERSHIP),
 335             reference: "issue #37872 <https://github.com/rust-lang/rust/issues/37872>",
 336             edition: None,
 337         },
 338         FutureIncompatibleInfo {
 339             id: LintId::of(LEGACY_CONSTRUCTOR_VISIBILITY),
 340             reference: "issue #39207 <https://github.com/rust-lang/rust/issues/39207>",
 341             edition: None,
 342         },
 343         FutureIncompatibleInfo {
 344             id: LintId::of(MISSING_FRAGMENT_SPECIFIER),
 345             reference: "issue #40107 <https://github.com/rust-lang/rust/issues/40107>",
 346             edition: None,
 347         },
 348         FutureIncompatibleInfo {
 349             id: LintId::of(ILLEGAL_FLOATING_POINT_LITERAL_PATTERN),
 350             reference: "issue #41620 <https://github.com/rust-lang/rust/issues/41620>",
 351             edition: None,
 352         },
 353         FutureIncompatibleInfo {
 354             id: LintId::of(ANONYMOUS_PARAMETERS),
 355             reference: "issue #41686 <https://github.com/rust-lang/rust/issues/41686>",
 356             edition: Some(Edition::Edition2018),
 357         },
 358         FutureIncompatibleInfo {
 359             id: LintId::of(PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES),
 360             reference: "issue #42238 <https://github.com/rust-lang/rust/issues/42238>",
 361             edition: None,
 362         },
 363         FutureIncompatibleInfo {
 364             id: LintId::of(LATE_BOUND_LIFETIME_ARGUMENTS),
 365             reference: "issue #42868 <https://github.com/rust-lang/rust/issues/42868>",
 366             edition: None,
 367         },
 368         FutureIncompatibleInfo {
 369             id: LintId::of(SAFE_PACKED_BORROWS),
 370             reference: "issue #46043 <https://github.com/rust-lang/rust/issues/46043>",
 371             edition: None,
 372         },
 373         FutureIncompatibleInfo {
 374             id: LintId::of(INCOHERENT_FUNDAMENTAL_IMPLS),
 375             reference: "issue #46205 <https://github.com/rust-lang/rust/issues/46205>",
 376             edition: None,
 377         },
 378         FutureIncompatibleInfo {
 379             id: LintId::of(ORDER_DEPENDENT_TRAIT_OBJECTS),
 380             reference: "issue #56484 <https://github.com/rust-lang/rust/issues/56484>",
 381             edition: None,
 382         },
 383         FutureIncompatibleInfo {
 384             id: LintId::of(TYVAR_BEHIND_RAW_POINTER),
 385             reference: "issue #46906 <https://github.com/rust-lang/rust/issues/46906>",
 386             edition: Some(Edition::Edition2018),
 387         },
 388         FutureIncompatibleInfo {
 389             id: LintId::of(UNSTABLE_NAME_COLLISIONS),
 390             reference: "issue #48919 <https://github.com/rust-lang/rust/issues/48919>",
 391             edition: None,
 392             // Note: this item represents future incompatibility of all unstable functions in the
 393             //       standard library, and thus should never be removed or changed to an error.
 394         },
 395         FutureIncompatibleInfo {
 396             id: LintId::of(ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE),
 397             reference: "issue #53130 <https://github.com/rust-lang/rust/issues/53130>",
 398             edition: Some(Edition::Edition2018),
 399         },
 400         FutureIncompatibleInfo {
 401             id: LintId::of(WHERE_CLAUSES_OBJECT_SAFETY),
 402             reference: "issue #51443 <https://github.com/rust-lang/rust/issues/51443>",
 403             edition: None,
 404         },
 405         FutureIncompatibleInfo {
 406             id: LintId::of(PROC_MACRO_DERIVE_RESOLUTION_FALLBACK),
 407             reference: "issue #50504 <https://github.com/rust-lang/rust/issues/50504>",
 408             edition: None,
 409         },
 410         FutureIncompatibleInfo {
 411             id: LintId::of(QUESTION_MARK_MACRO_SEP),
 412             reference: "issue #48075 <https://github.com/rust-lang/rust/issues/48075>",
 413             edition: Some(Edition::Edition2018),
 414         },
 415         FutureIncompatibleInfo {
 416             id: LintId::of(MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS),
 417             reference: "issue #52234 <https://github.com/rust-lang/rust/issues/52234>",
 418             edition: None,
 419         },
 420         FutureIncompatibleInfo {
 421             id: LintId::of(ILL_FORMED_ATTRIBUTE_INPUT),
 422             reference: "issue #57571 <https://github.com/rust-lang/rust/issues/57571>",
 423             edition: None,
 424         },
 425         FutureIncompatibleInfo {
 426             id: LintId::of(AMBIGUOUS_ASSOCIATED_ITEMS),
 427             reference: "issue #57644 <https://github.com/rust-lang/rust/issues/57644>",
 428             edition: None,
 429         },
 430         FutureIncompatibleInfo {
 431             id: LintId::of(DUPLICATE_MATCHER_BINDING_NAME),
 432             reference: "issue #57593 <https://github.com/rust-lang/rust/issues/57593>",
 433             edition: None,
 434         },
 435         FutureIncompatibleInfo {
 436             id: LintId::of(NESTED_IMPL_TRAIT),
 437             reference: "issue #59014 <https://github.com/rust-lang/rust/issues/59014>",
 438             edition: None,
 439         },
 440         ]);
 441
 442     // Register renamed and removed lints.
 443     store.register_renamed("single_use_lifetime", "single_use_lifetimes");
 444     store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
 445     store.register_renamed("bare_trait_object", "bare_trait_objects");
 446     store.register_renamed("unstable_name_collision", "unstable_name_collisions");
 447     store.register_renamed("unused_doc_comment", "unused_doc_comments");
 448     store.register_renamed("async_idents", "keyword_idents");
 449     store.register_removed("unknown_features", "replaced by an error");
 450     store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
 451     store.register_removed("negate_unsigned", "cast a signed value instead");
 452     store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
 453     // Register lint group aliases.
 454     store.register_group_alias("nonstandard_style", "bad_style");
 455     // This was renamed to `raw_pointer_derive`, which was then removed,
 456     // so it is also considered removed.
 457     store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
 458     store.register_removed("drop_with_repr_extern", "drop flags have been removed");
 459     store.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
 460     store.register_removed("deprecated_attr", "use `deprecated` instead");
 461     store.register_removed("transmute_from_fn_item_types",
 462         "always cast functions before transmuting them");
 463     store.register_removed("hr_lifetime_in_assoc_type",
 464         "converted into hard error, see https://github.com/rust-lang/rust/issues/33685");
 465     store.register_removed("inaccessible_extern_crate",
 466         "converted into hard error, see https://github.com/rust-lang/rust/issues/36886");
 467     store.register_removed("super_or_self_in_global_path",
 468         "converted into hard error, see https://github.com/rust-lang/rust/issues/36888");
 469     store.register_removed("overlapping_inherent_impls",
 470         "converted into hard error, see https://github.com/rust-lang/rust/issues/36889");
 471     store.register_removed("illegal_floating_point_constant_pattern",
 472         "converted into hard error, see https://github.com/rust-lang/rust/issues/36890");
 473     store.register_removed("illegal_struct_or_enum_constant_pattern",
 474         "converted into hard error, see https://github.com/rust-lang/rust/issues/36891");
 475     store.register_removed("lifetime_underscore",
 476         "converted into hard error, see https://github.com/rust-lang/rust/issues/36892");
 477     store.register_removed("extra_requirement_in_impl",
 478         "converted into hard error, see https://github.com/rust-lang/rust/issues/37166");
 479     store.register_removed("legacy_imports",
 480         "converted into hard error, see https://github.com/rust-lang/rust/issues/38260");
 481     store.register_removed("coerce_never",
 482         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950");
 483     store.register_removed("resolve_trait_on_defaulted_unit",
 484         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950");
 485     store.register_removed("private_no_mangle_fns",
 486         "no longer a warning, #[no_mangle] functions always exported");
 487     store.register_removed("private_no_mangle_statics",
 488         "no longer a warning, #[no_mangle] statics always exported");
 489     store.register_removed("bad_repr",
 490         "replaced with a generic attribute input check");
 491 }
 492
 493 pub fn register_internals(store: &mut lint::LintStore, sess: Option<&Session>) {
 494     store.register_early_pass(sess, false, false, box DefaultHashTypes::new());
 495     store.register_late_pass(sess, false, false, false, box TyKindUsage);
 496     store.register_group(
 497         sess,
 498         false,
 499         "internal",
 500         None,
 501         vec![
 502             LintId::of(DEFAULT_HASH_TYPES),
 503             LintId::of(USAGE_OF_TY_TYKIND),
 504         ],
 505     );
 506 }