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