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_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
  13       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
  14       html_root_url = "https://doc.rust-lang.org/nightly/")]
  15
  16 #![cfg_attr(test, feature(test))]
  17 #![feature(box_patterns)]
  18 #![feature(box_syntax)]
  19 #![feature(nll)]
  20 #![feature(rustc_diagnostic_macros)]
  21
  22 #![recursion_limit="256"]
  23
  24 #[macro_use]
  25 extern crate syntax;
  26 #[macro_use]
  27 extern crate rustc;
  28 #[macro_use]
  29 extern crate log;
  30 extern crate rustc_target;
  31 extern crate syntax_pos;
  32 extern crate rustc_data_structures;
  33
  34 mod diagnostics;
  35 mod nonstandard_style;
  36 pub mod builtin;
  37 mod types;
  38 mod unused;
  39
  40 use rustc::lint;
  41 use rustc::lint::{EarlyContext, LateContext, LateLintPass, EarlyLintPass, LintPass, LintArray};
  42 use rustc::lint::builtin::{
  43     BARE_TRAIT_OBJECTS,
  44     ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  45     ELIDED_LIFETIMES_IN_PATHS,
  46     EXPLICIT_OUTLIVES_REQUIREMENTS,
  47     INTRA_DOC_LINK_RESOLUTION_FAILURE,
  48     MISSING_DOC_CODE_EXAMPLES,
  49     PRIVATE_DOC_TESTS,
  50     parser::QUESTION_MARK_MACRO_SEP,
  51     parser::ILL_FORMED_ATTRIBUTE_INPUT,
  52 };
  53 use rustc::session;
  54 use rustc::util;
  55 use rustc::hir;
  56
  57 use syntax::ast;
  58 use syntax::edition::Edition;
  59 use syntax_pos::Span;
  60
  61 use session::Session;
  62 use lint::LintId;
  63 use lint::FutureIncompatibleInfo;
  64
  65 use nonstandard_style::*;
  66 use builtin::*;
  67 use types::*;
  68 use unused::*;
  69
  70 /// Useful for other parts of the compiler.
  71 pub use builtin::SoftLints;
  72
  73 macro_rules! pre_expansion_lint_passes {
  74     ($macro:path, $args:tt) => (
  75         $macro!($args, [
  76             KeywordIdents: KeywordIdents,
  77         ]);
  78     )
  79 }
  80
  81 macro_rules! early_lint_passes {
  82     ($macro:path, $args:tt) => (
  83         $macro!($args, [
  84             UnusedParens: UnusedParens,
  85             UnusedImportBraces: UnusedImportBraces,
  86             UnsafeCode: UnsafeCode,
  87             AnonymousParameters: AnonymousParameters,
  88             UnusedDocComment: UnusedDocComment,
  89             EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns,
  90             NonCamelCaseTypes: NonCamelCaseTypes,
  91             DeprecatedAttr: DeprecatedAttr::new(),
  92         ]);
  93     )
  94 }
  95
  96 macro_rules! declare_combined_early_pass {
  97     ([$name:ident], $passes:tt) => (
  98         early_lint_methods!(declare_combined_early_lint_pass, [pub $name, $passes]);
  99     )
 100 }
 101
 102 pre_expansion_lint_passes!(declare_combined_early_pass, [BuiltinCombinedPreExpansionLintPass]);
 103 early_lint_passes!(declare_combined_early_pass, [BuiltinCombinedEarlyLintPass]);
 104
 105 /// Tell the `LintStore` about all the built-in lints (the ones
 106 /// defined in this crate and the ones defined in
 107 /// `rustc::lint::builtin`).
 108 pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
 109     macro_rules! add_lint_group {
 110         ($sess:ident, $name:expr, $($lint:ident),*) => (
 111             store.register_group($sess, false, $name, None, vec![$(LintId::of($lint)),*]);
 112         )
 113     }
 114
 115     macro_rules! register_passes {
 116         ([$method:ident], [$($passes:ident: $constructor:expr,)*]) => (
 117             $(
 118                 store.$method(sess, false, false, box $constructor);
 119             )*
 120         )
 121     }
 122
 123     if sess.map(|sess| sess.opts.debugging_opts.no_interleave_lints).unwrap_or(false) {
 124         pre_expansion_lint_passes!(register_passes, [register_pre_expansion_pass]);
 125         early_lint_passes!(register_passes, [register_early_pass]);
 126     } else {
 127         store.register_pre_expansion_pass(
 128             sess,
 129             false,
 130             true,
 131             box BuiltinCombinedPreExpansionLintPass::new()
 132         );
 133         store.register_early_pass(sess, false, true, box BuiltinCombinedEarlyLintPass::new());
 134     }
 135
 136     late_lint_methods!(declare_combined_late_lint_pass, [BuiltinCombinedLateLintPass, [
 137         HardwiredLints: HardwiredLints,
 138         WhileTrue: WhileTrue,
 139         ImproperCTypes: ImproperCTypes,
 140         VariantSizeDifferences: VariantSizeDifferences,
 141         BoxPointers: BoxPointers,
 142         UnusedAttributes: UnusedAttributes,
 143         PathStatements: PathStatements,
 144         UnusedResults: UnusedResults,
 145         NonSnakeCase: NonSnakeCase,
 146         NonUpperCaseGlobals: NonUpperCaseGlobals,
 147         NonShorthandFieldPatterns: NonShorthandFieldPatterns,
 148         UnusedAllocation: UnusedAllocation,
 149         MissingCopyImplementations: MissingCopyImplementations,
 150         UnstableFeatures: UnstableFeatures,
 151         InvalidNoMangleItems: InvalidNoMangleItems,
 152         PluginAsLibrary: PluginAsLibrary,
 153         MutableTransmutes: MutableTransmutes,
 154         UnionsWithDropFields: UnionsWithDropFields,
 155         UnreachablePub: UnreachablePub,
 156         UnnameableTestItems: UnnameableTestItems::new(),
 157         TypeAliasBounds: TypeAliasBounds,
 158         UnusedBrokenConst: UnusedBrokenConst,
 159         TrivialConstraints: TrivialConstraints,
 160         TypeLimits: TypeLimits::new(),
 161         MissingDoc: MissingDoc::new(),
 162         MissingDebugImplementations: MissingDebugImplementations::new(),
 163         ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
 164     ]], ['tcx]);
 165
 166     store.register_late_pass(sess, false, box BuiltinCombinedLateLintPass::new());
 167
 168     add_lint_group!(sess,
 169                     "nonstandard_style",
 170                     NON_CAMEL_CASE_TYPES,
 171                     NON_SNAKE_CASE,
 172                     NON_UPPER_CASE_GLOBALS);
 173
 174     add_lint_group!(sess,
 175                     "unused",
 176                     UNUSED_IMPORTS,
 177                     UNUSED_VARIABLES,
 178                     UNUSED_ASSIGNMENTS,
 179                     DEAD_CODE,
 180                     UNUSED_MUT,
 181                     UNREACHABLE_CODE,
 182                     UNREACHABLE_PATTERNS,
 183                     UNUSED_MUST_USE,
 184                     UNUSED_UNSAFE,
 185                     PATH_STATEMENTS,
 186                     UNUSED_ATTRIBUTES,
 187                     UNUSED_MACROS,
 188                     UNUSED_ALLOCATION,
 189                     UNUSED_DOC_COMMENTS,
 190                     UNUSED_EXTERN_CRATES,
 191                     UNUSED_FEATURES,
 192                     UNUSED_LABELS,
 193                     UNUSED_PARENS);
 194
 195     add_lint_group!(sess,
 196                     "rust_2018_idioms",
 197                     BARE_TRAIT_OBJECTS,
 198                     UNUSED_EXTERN_CRATES,
 199                     ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
 200                     ELIDED_LIFETIMES_IN_PATHS,
 201                     EXPLICIT_OUTLIVES_REQUIREMENTS
 202
 203                     // FIXME(#52665, #47816) not always applicable and not all
 204                     // macros are ready for this yet.
 205                     // UNREACHABLE_PUB,
 206
 207                     // FIXME macro crates are not up for this yet, too much
 208                     // breakage is seen if we try to encourage this lint.
 209                     // MACRO_USE_EXTERN_CRATE,
 210                     );
 211
 212     add_lint_group!(sess,
 213                     "rustdoc",
 214                     INTRA_DOC_LINK_RESOLUTION_FAILURE,
 215                     MISSING_DOC_CODE_EXAMPLES,
 216                     PRIVATE_DOC_TESTS);
 217
 218     // Guidelines for creating a future incompatibility lint:
 219     //
 220     // - Create a lint defaulting to warn as normal, with ideally the same error
 221     //   message you would normally give
 222     // - Add a suitable reference, typically an RFC or tracking issue. Go ahead
 223     //   and include the full URL, sort items in ascending order of issue numbers.
 224     // - Later, change lint to error
 225     // - Eventually, remove lint
 226     store.register_future_incompatible(sess, vec![
 227         FutureIncompatibleInfo {
 228             id: LintId::of(PRIVATE_IN_PUBLIC),
 229             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
 230             edition: None,
 231         },
 232         FutureIncompatibleInfo {
 233             id: LintId::of(EXTERNAL_PRIVATE_DEPENDENCY),
 234             reference: "issue #44663 <https://github.com/rust-lang/rust/issues/44663>",
 235             edition: None,
 236         },
 237         FutureIncompatibleInfo {
 238             id: LintId::of(PUB_USE_OF_PRIVATE_EXTERN_CRATE),
 239             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
 240             edition: None,
 241         },
 242         FutureIncompatibleInfo {
 243             id: LintId::of(PATTERNS_IN_FNS_WITHOUT_BODY),
 244             reference: "issue #35203 <https://github.com/rust-lang/rust/issues/35203>",
 245             edition: None,
 246         },
 247         FutureIncompatibleInfo {
 248             id: LintId::of(DUPLICATE_MACRO_EXPORTS),
 249             reference: "issue #35896 <https://github.com/rust-lang/rust/issues/35896>",
 250             edition: Some(Edition::Edition2018),
 251         },
 252         FutureIncompatibleInfo {
 253             id: LintId::of(KEYWORD_IDENTS),
 254             reference: "issue #49716 <https://github.com/rust-lang/rust/issues/49716>",
 255             edition: Some(Edition::Edition2018),
 256         },
 257         FutureIncompatibleInfo {
 258             id: LintId::of(SAFE_EXTERN_STATICS),
 259             reference: "issue #36247 <https://github.com/rust-lang/rust/issues/36247>",
 260             edition: None,
 261         },
 262         FutureIncompatibleInfo {
 263             id: LintId::of(INVALID_TYPE_PARAM_DEFAULT),
 264             reference: "issue #36887 <https://github.com/rust-lang/rust/issues/36887>",
 265             edition: None,
 266         },
 267         FutureIncompatibleInfo {
 268             id: LintId::of(LEGACY_DIRECTORY_OWNERSHIP),
 269             reference: "issue #37872 <https://github.com/rust-lang/rust/issues/37872>",
 270             edition: None,
 271         },
 272         FutureIncompatibleInfo {
 273             id: LintId::of(LEGACY_CONSTRUCTOR_VISIBILITY),
 274             reference: "issue #39207 <https://github.com/rust-lang/rust/issues/39207>",
 275             edition: None,
 276         },
 277         FutureIncompatibleInfo {
 278             id: LintId::of(MISSING_FRAGMENT_SPECIFIER),
 279             reference: "issue #40107 <https://github.com/rust-lang/rust/issues/40107>",
 280             edition: None,
 281         },
 282         FutureIncompatibleInfo {
 283             id: LintId::of(ILLEGAL_FLOATING_POINT_LITERAL_PATTERN),
 284             reference: "issue #41620 <https://github.com/rust-lang/rust/issues/41620>",
 285             edition: None,
 286         },
 287         FutureIncompatibleInfo {
 288             id: LintId::of(ANONYMOUS_PARAMETERS),
 289             reference: "issue #41686 <https://github.com/rust-lang/rust/issues/41686>",
 290             edition: Some(Edition::Edition2018),
 291         },
 292         FutureIncompatibleInfo {
 293             id: LintId::of(PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES),
 294             reference: "issue #42238 <https://github.com/rust-lang/rust/issues/42238>",
 295             edition: None,
 296         },
 297         FutureIncompatibleInfo {
 298             id: LintId::of(LATE_BOUND_LIFETIME_ARGUMENTS),
 299             reference: "issue #42868 <https://github.com/rust-lang/rust/issues/42868>",
 300             edition: None,
 301         },
 302         FutureIncompatibleInfo {
 303             id: LintId::of(SAFE_PACKED_BORROWS),
 304             reference: "issue #46043 <https://github.com/rust-lang/rust/issues/46043>",
 305             edition: None,
 306         },
 307         FutureIncompatibleInfo {
 308             id: LintId::of(INCOHERENT_FUNDAMENTAL_IMPLS),
 309             reference: "issue #46205 <https://github.com/rust-lang/rust/issues/46205>",
 310             edition: None,
 311         },
 312         FutureIncompatibleInfo {
 313             id: LintId::of(ORDER_DEPENDENT_TRAIT_OBJECTS),
 314             reference: "issue #56484 <https://github.com/rust-lang/rust/issues/56484>",
 315             edition: None,
 316         },
 317         FutureIncompatibleInfo {
 318             id: LintId::of(TYVAR_BEHIND_RAW_POINTER),
 319             reference: "issue #46906 <https://github.com/rust-lang/rust/issues/46906>",
 320             edition: Some(Edition::Edition2018),
 321         },
 322         FutureIncompatibleInfo {
 323             id: LintId::of(UNSTABLE_NAME_COLLISIONS),
 324             reference: "issue #48919 <https://github.com/rust-lang/rust/issues/48919>",
 325             edition: None,
 326             // Note: this item represents future incompatibility of all unstable functions in the
 327             //       standard library, and thus should never be removed or changed to an error.
 328         },
 329         FutureIncompatibleInfo {
 330             id: LintId::of(ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE),
 331             reference: "issue #53130 <https://github.com/rust-lang/rust/issues/53130>",
 332             edition: Some(Edition::Edition2018),
 333         },
 334         FutureIncompatibleInfo {
 335             id: LintId::of(WHERE_CLAUSES_OBJECT_SAFETY),
 336             reference: "issue #51443 <https://github.com/rust-lang/rust/issues/51443>",
 337             edition: None,
 338         },
 339         FutureIncompatibleInfo {
 340             id: LintId::of(PROC_MACRO_DERIVE_RESOLUTION_FALLBACK),
 341             reference: "issue #50504 <https://github.com/rust-lang/rust/issues/50504>",
 342             edition: None,
 343         },
 344         FutureIncompatibleInfo {
 345             id: LintId::of(QUESTION_MARK_MACRO_SEP),
 346             reference: "issue #48075 <https://github.com/rust-lang/rust/issues/48075>",
 347             edition: Some(Edition::Edition2018),
 348         },
 349         FutureIncompatibleInfo {
 350             id: LintId::of(MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS),
 351             reference: "issue #52234 <https://github.com/rust-lang/rust/issues/52234>",
 352             edition: None,
 353         },
 354         FutureIncompatibleInfo {
 355             id: LintId::of(ILL_FORMED_ATTRIBUTE_INPUT),
 356             reference: "issue #57571 <https://github.com/rust-lang/rust/issues/57571>",
 357             edition: None,
 358         },
 359         FutureIncompatibleInfo {
 360             id: LintId::of(AMBIGUOUS_ASSOCIATED_ITEMS),
 361             reference: "issue #57644 <https://github.com/rust-lang/rust/issues/57644>",
 362             edition: None,
 363         },
 364         ]);
 365
 366     // Register renamed and removed lints.
 367     store.register_renamed("single_use_lifetime", "single_use_lifetimes");
 368     store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
 369     store.register_renamed("bare_trait_object", "bare_trait_objects");
 370     store.register_renamed("unstable_name_collision", "unstable_name_collisions");
 371     store.register_renamed("unused_doc_comment", "unused_doc_comments");
 372     store.register_renamed("async_idents", "keyword_idents");
 373     store.register_removed("unknown_features", "replaced by an error");
 374     store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
 375     store.register_removed("negate_unsigned", "cast a signed value instead");
 376     store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
 377     // Register lint group aliases.
 378     store.register_group_alias("nonstandard_style", "bad_style");
 379     // This was renamed to `raw_pointer_derive`, which was then removed,
 380     // so it is also considered removed.
 381     store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
 382     store.register_removed("drop_with_repr_extern", "drop flags have been removed");
 383     store.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
 384     store.register_removed("deprecated_attr", "use `deprecated` instead");
 385     store.register_removed("transmute_from_fn_item_types",
 386         "always cast functions before transmuting them");
 387     store.register_removed("hr_lifetime_in_assoc_type",
 388         "converted into hard error, see https://github.com/rust-lang/rust/issues/33685");
 389     store.register_removed("inaccessible_extern_crate",
 390         "converted into hard error, see https://github.com/rust-lang/rust/issues/36886");
 391     store.register_removed("super_or_self_in_global_path",
 392         "converted into hard error, see https://github.com/rust-lang/rust/issues/36888");
 393     store.register_removed("overlapping_inherent_impls",
 394         "converted into hard error, see https://github.com/rust-lang/rust/issues/36889");
 395     store.register_removed("illegal_floating_point_constant_pattern",
 396         "converted into hard error, see https://github.com/rust-lang/rust/issues/36890");
 397     store.register_removed("illegal_struct_or_enum_constant_pattern",
 398         "converted into hard error, see https://github.com/rust-lang/rust/issues/36891");
 399     store.register_removed("lifetime_underscore",
 400         "converted into hard error, see https://github.com/rust-lang/rust/issues/36892");
 401     store.register_removed("extra_requirement_in_impl",
 402         "converted into hard error, see https://github.com/rust-lang/rust/issues/37166");
 403     store.register_removed("legacy_imports",
 404         "converted into hard error, see https://github.com/rust-lang/rust/issues/38260");
 405     store.register_removed("coerce_never",
 406         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950");
 407     store.register_removed("resolve_trait_on_defaulted_unit",
 408         "converted into hard error, see https://github.com/rust-lang/rust/issues/48950");
 409     store.register_removed("private_no_mangle_fns",
 410         "no longer a warning, #[no_mangle] functions always exported");
 411     store.register_removed("private_no_mangle_statics",
 412         "no longer a warning, #[no_mangle] statics always exported");
 413     store.register_removed("bad_repr",
 414         "replaced with a generic attribute input check");
 415 }