compiler/rustc_lint_defs/src/lib.rs

   1 #![feature(min_specialization)]
   2 #![deny(rustc::untranslatable_diagnostic)]
   3 #![deny(rustc::diagnostic_outside_of_impl)]
   4
   5 #[macro_use]
   6 extern crate rustc_macros;
   7
   8 pub use self::Level::*;
   9 use rustc_ast::node_id::{NodeId, NodeMap};
  10 use rustc_ast::{AttrId, Attribute};
  11 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
  12 use rustc_error_messages::{DiagnosticMessage, MultiSpan};
  13 use rustc_hir::HashStableContext;
  14 use rustc_hir::HirId;
  15 use rustc_span::edition::Edition;
  16 use rustc_span::{sym, symbol::Ident, Span, Symbol};
  17 use rustc_target::spec::abi::Abi;
  18
  19 use serde::{Deserialize, Serialize};
  20
  21 pub mod builtin;
  22
  23 #[macro_export]
  24 macro_rules! pluralize {
  25     ($x:expr) => {
  26         if $x != 1 { "s" } else { "" }
  27     };
  28     ("has", $x:expr) => {
  29         if $x == 1 { "has" } else { "have" }
  30     };
  31     ("is", $x:expr) => {
  32         if $x == 1 { "is" } else { "are" }
  33     };
  34     ("was", $x:expr) => {
  35         if $x == 1 { "was" } else { "were" }
  36     };
  37     ("this", $x:expr) => {
  38         if $x == 1 { "this" } else { "these" }
  39     };
  40 }
  41
  42 /// Indicates the confidence in the correctness of a suggestion.
  43 ///
  44 /// All suggestions are marked with an `Applicability`. Tools use the applicability of a suggestion
  45 /// to determine whether it should be automatically applied or if the user should be consulted
  46 /// before applying the suggestion.
  47 #[derive(Copy, Clone, Debug, Hash, Encodable, Decodable, Serialize, Deserialize)]
  48 #[derive(PartialEq, Eq, PartialOrd, Ord)]
  49 pub enum Applicability {
  50     /// The suggestion is definitely what the user intended, or maintains the exact meaning of the code.
  51     /// This suggestion should be automatically applied.
  52     ///
  53     /// In case of multiple `MachineApplicable` suggestions (whether as part of
  54     /// the same `multipart_suggestion` or not), all of them should be
  55     /// automatically applied.
  56     MachineApplicable,
  57
  58     /// The suggestion may be what the user intended, but it is uncertain. The suggestion should
  59     /// result in valid Rust code if it is applied.
  60     MaybeIncorrect,
  61
  62     /// The suggestion contains placeholders like `(...)` or `{ /* fields */ }`. The suggestion
  63     /// cannot be applied automatically because it will not result in valid Rust code. The user
  64     /// will need to fill in the placeholders.
  65     HasPlaceholders,
  66
  67     /// The applicability of the suggestion is unknown.
  68     Unspecified,
  69 }
  70
  71 /// Each lint expectation has a `LintExpectationId` assigned by the `LintLevelsBuilder`.
  72 /// Expected `Diagnostic`s get the lint level `Expect` which stores the `LintExpectationId`
  73 /// to match it with the actual expectation later on.
  74 ///
  75 /// The `LintExpectationId` has to be stable between compilations, as diagnostic
  76 /// instances might be loaded from cache. Lint messages can be emitted during an
  77 /// `EarlyLintPass` operating on the AST and during a `LateLintPass` traversing the
  78 /// HIR tree. The AST doesn't have enough information to create a stable id. The
  79 /// `LintExpectationId` will instead store the [`AttrId`] defining the expectation.
  80 /// These `LintExpectationId` will be updated to use the stable [`HirId`] once the
  81 /// AST has been lowered. The transformation is done by the `LintLevelsBuilder`
  82 ///
  83 /// Each lint inside the `expect` attribute is tracked individually, the `lint_index`
  84 /// identifies the lint inside the attribute and ensures that the IDs are unique.
  85 ///
  86 /// The index values have a type of `u16` to reduce the size of the `LintExpectationId`.
  87 /// It's reasonable to assume that no user will define 2^16 attributes on one node or
  88 /// have that amount of lints listed. `u16` values should therefore suffice.
  89 #[derive(Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Debug, Hash, Encodable, Decodable)]
  90 pub enum LintExpectationId {
  91     /// Used for lints emitted during the `EarlyLintPass`. This id is not
  92     /// hash stable and should not be cached.
  93     Unstable { attr_id: AttrId, lint_index: Option<u16> },
  94     /// The [`HirId`] that the lint expectation is attached to. This id is
  95     /// stable and can be cached. The additional index ensures that nodes with
  96     /// several expectations can correctly match diagnostics to the individual
  97     /// expectation.
  98     Stable { hir_id: HirId, attr_index: u16, lint_index: Option<u16>, attr_id: Option<AttrId> },
  99 }
 100
 101 impl LintExpectationId {
 102     pub fn is_stable(&self) -> bool {
 103         match self {
 104             LintExpectationId::Unstable { .. } => false,
 105             LintExpectationId::Stable { .. } => true,
 106         }
 107     }
 108
 109     pub fn get_lint_index(&self) -> Option<u16> {
 110         let (LintExpectationId::Unstable { lint_index, .. }
 111         | LintExpectationId::Stable { lint_index, .. }) = self;
 112
 113         *lint_index
 114     }
 115
 116     pub fn set_lint_index(&mut self, new_lint_index: Option<u16>) {
 117         let (LintExpectationId::Unstable { ref mut lint_index, .. }
 118         | LintExpectationId::Stable { ref mut lint_index, .. }) = self;
 119
 120         *lint_index = new_lint_index
 121     }
 122
 123     /// Prepares the id for hashing. Removes references to the ast.
 124     /// Should only be called when the id is stable.
 125     pub fn normalize(self) -> Self {
 126         match self {
 127             Self::Stable { hir_id, attr_index, lint_index, .. } => {
 128                 Self::Stable { hir_id, attr_index, lint_index, attr_id: None }
 129             }
 130             Self::Unstable { .. } => {
 131                 unreachable!("`normalize` called when `ExpectationId` is unstable")
 132             }
 133         }
 134     }
 135 }
 136
 137 impl<HCX: rustc_hir::HashStableContext> HashStable<HCX> for LintExpectationId {
 138     #[inline]
 139     fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
 140         match self {
 141             LintExpectationId::Stable {
 142                 hir_id,
 143                 attr_index,
 144                 lint_index: Some(lint_index),
 145                 attr_id: _,
 146             } => {
 147                 hir_id.hash_stable(hcx, hasher);
 148                 attr_index.hash_stable(hcx, hasher);
 149                 lint_index.hash_stable(hcx, hasher);
 150             }
 151             _ => {
 152                 unreachable!(
 153                     "HashStable should only be called for filled and stable `LintExpectationId`"
 154                 )
 155             }
 156         }
 157     }
 158 }
 159
 160 impl<HCX: rustc_hir::HashStableContext> ToStableHashKey<HCX> for LintExpectationId {
 161     type KeyType = (HirId, u16, u16);
 162
 163     #[inline]
 164     fn to_stable_hash_key(&self, _: &HCX) -> Self::KeyType {
 165         match self {
 166             LintExpectationId::Stable {
 167                 hir_id,
 168                 attr_index,
 169                 lint_index: Some(lint_index),
 170                 attr_id: _,
 171             } => (*hir_id, *attr_index, *lint_index),
 172             _ => {
 173                 unreachable!("HashStable should only be called for a filled `LintExpectationId`")
 174             }
 175         }
 176     }
 177 }
 178
 179 /// Setting for how to handle a lint.
 180 ///
 181 /// See: <https://doc.rust-lang.org/rustc/lints/levels.html>
 182 #[derive(Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Debug, Hash, HashStable_Generic)]
 183 pub enum Level {
 184     /// The `allow` level will not issue any message.
 185     Allow,
 186     /// The `expect` level will suppress the lint message but in turn produce a message
 187     /// if the lint wasn't issued in the expected scope. `Expect` should not be used as
 188     /// an initial level for a lint.
 189     ///
 190     /// Note that this still means that the lint is enabled in this position and should
 191     /// be emitted, this will in turn fulfill the expectation and suppress the lint.
 192     ///
 193     /// See RFC 2383.
 194     ///
 195     /// The [`LintExpectationId`] is used to later link a lint emission to the actual
 196     /// expectation. It can be ignored in most cases.
 197     Expect(LintExpectationId),
 198     /// The `warn` level will produce a warning if the lint was violated, however the
 199     /// compiler will continue with its execution.
 200     Warn,
 201     /// This lint level is a special case of [`Warn`], that can't be overridden. This is used
 202     /// to ensure that a lint can't be suppressed. This lint level can currently only be set
 203     /// via the console and is therefore session specific.
 204     ///
 205     /// The [`LintExpectationId`] is intended to fulfill expectations marked via the
 206     /// `#[expect]` attribute, that will still be suppressed due to the level.
 207     ForceWarn(Option<LintExpectationId>),
 208     /// The `deny` level will produce an error and stop further execution after the lint
 209     /// pass is complete.
 210     Deny,
 211     /// `Forbid` is equivalent to the `deny` level but can't be overwritten like the previous
 212     /// levels.
 213     Forbid,
 214 }
 215
 216 impl Level {
 217     /// Converts a level to a lower-case string.
 218     pub fn as_str(self) -> &'static str {
 219         match self {
 220             Level::Allow => "allow",
 221             Level::Expect(_) => "expect",
 222             Level::Warn => "warn",
 223             Level::ForceWarn(_) => "force-warn",
 224             Level::Deny => "deny",
 225             Level::Forbid => "forbid",
 226         }
 227     }
 228
 229     /// Converts a lower-case string to a level. This will never construct the expect
 230     /// level as that would require a [`LintExpectationId`]
 231     pub fn from_str(x: &str) -> Option<Level> {
 232         match x {
 233             "allow" => Some(Level::Allow),
 234             "warn" => Some(Level::Warn),
 235             "deny" => Some(Level::Deny),
 236             "forbid" => Some(Level::Forbid),
 237             "expect" | _ => None,
 238         }
 239     }
 240
 241     /// Converts a symbol to a level.
 242     pub fn from_attr(attr: &Attribute) -> Option<Level> {
 243         match attr.name_or_empty() {
 244             sym::allow => Some(Level::Allow),
 245             sym::expect => Some(Level::Expect(LintExpectationId::Unstable {
 246                 attr_id: attr.id,
 247                 lint_index: None,
 248             })),
 249             sym::warn => Some(Level::Warn),
 250             sym::deny => Some(Level::Deny),
 251             sym::forbid => Some(Level::Forbid),
 252             _ => None,
 253         }
 254     }
 255
 256     pub fn is_error(self) -> bool {
 257         match self {
 258             Level::Allow | Level::Expect(_) | Level::Warn | Level::ForceWarn(_) => false,
 259             Level::Deny | Level::Forbid => true,
 260         }
 261     }
 262
 263     pub fn get_expectation_id(&self) -> Option<LintExpectationId> {
 264         match self {
 265             Level::Expect(id) | Level::ForceWarn(Some(id)) => Some(*id),
 266             _ => None,
 267         }
 268     }
 269 }
 270
 271 /// Specification of a single lint.
 272 #[derive(Copy, Clone, Debug)]
 273 pub struct Lint {
 274     /// A string identifier for the lint.
 275     ///
 276     /// This identifies the lint in attributes and in command-line arguments.
 277     /// In those contexts it is always lowercase, but this field is compared
 278     /// in a way which is case-insensitive for ASCII characters. This allows
 279     /// `declare_lint!()` invocations to follow the convention of upper-case
 280     /// statics without repeating the name.
 281     ///
 282     /// The name is written with underscores, e.g., "unused_imports".
 283     /// On the command line, underscores become dashes.
 284     ///
 285     /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html#lint-naming>
 286     /// for naming guidelines.
 287     pub name: &'static str,
 288
 289     /// Default level for the lint.
 290     ///
 291     /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html#diagnostic-levels>
 292     /// for guidelines on choosing a default level.
 293     pub default_level: Level,
 294
 295     /// Description of the lint or the issue it detects.
 296     ///
 297     /// e.g., "imports that are never used"
 298     pub desc: &'static str,
 299
 300     /// Starting at the given edition, default to the given lint level. If this is `None`, then use
 301     /// `default_level`.
 302     pub edition_lint_opts: Option<(Edition, Level)>,
 303
 304     /// `true` if this lint is reported even inside expansions of external macros.
 305     pub report_in_external_macro: bool,
 306
 307     pub future_incompatible: Option<FutureIncompatibleInfo>,
 308
 309     pub is_plugin: bool,
 310
 311     /// `Some` if this lint is feature gated, otherwise `None`.
 312     pub feature_gate: Option<Symbol>,
 313
 314     pub crate_level_only: bool,
 315 }
 316
 317 /// Extra information for a future incompatibility lint.
 318 #[derive(Copy, Clone, Debug)]
 319 pub struct FutureIncompatibleInfo {
 320     /// e.g., a URL for an issue/PR/RFC or error code
 321     pub reference: &'static str,
 322     /// The reason for the lint used by diagnostics to provide
 323     /// the right help message
 324     pub reason: FutureIncompatibilityReason,
 325     /// Whether to explain the reason to the user.
 326     ///
 327     /// Set to false for lints that already include a more detailed
 328     /// explanation.
 329     pub explain_reason: bool,
 330 }
 331
 332 /// The reason for future incompatibility
 333 #[derive(Copy, Clone, Debug)]
 334 pub enum FutureIncompatibilityReason {
 335     /// This will be an error in a future release
 336     /// for all editions
 337     FutureReleaseError,
 338     /// This will be an error in a future release, and
 339     /// Cargo should create a report even for dependencies
 340     FutureReleaseErrorReportNow,
 341     /// Code that changes meaning in some way in a
 342     /// future release.
 343     FutureReleaseSemanticsChange,
 344     /// Previously accepted code that will become an
 345     /// error in the provided edition
 346     EditionError(Edition),
 347     /// Code that changes meaning in some way in
 348     /// the provided edition
 349     EditionSemanticsChange(Edition),
 350     /// A custom reason.
 351     Custom(&'static str),
 352 }
 353
 354 impl FutureIncompatibilityReason {
 355     pub fn edition(self) -> Option<Edition> {
 356         match self {
 357             Self::EditionError(e) => Some(e),
 358             Self::EditionSemanticsChange(e) => Some(e),
 359             _ => None,
 360         }
 361     }
 362 }
 363
 364 impl FutureIncompatibleInfo {
 365     pub const fn default_fields_for_macro() -> Self {
 366         FutureIncompatibleInfo {
 367             reference: "",
 368             reason: FutureIncompatibilityReason::FutureReleaseError,
 369             explain_reason: true,
 370         }
 371     }
 372 }
 373
 374 impl Lint {
 375     pub const fn default_fields_for_macro() -> Self {
 376         Lint {
 377             name: "",
 378             default_level: Level::Forbid,
 379             desc: "",
 380             edition_lint_opts: None,
 381             is_plugin: false,
 382             report_in_external_macro: false,
 383             future_incompatible: None,
 384             feature_gate: None,
 385             crate_level_only: false,
 386         }
 387     }
 388
 389     /// Gets the lint's name, with ASCII letters converted to lowercase.
 390     pub fn name_lower(&self) -> String {
 391         self.name.to_ascii_lowercase()
 392     }
 393
 394     pub fn default_level(&self, edition: Edition) -> Level {
 395         self.edition_lint_opts
 396             .filter(|(e, _)| *e <= edition)
 397             .map(|(_, l)| l)
 398             .unwrap_or(self.default_level)
 399     }
 400 }
 401
 402 /// Identifies a lint known to the compiler.
 403 #[derive(Clone, Copy, Debug)]
 404 pub struct LintId {
 405     // Identity is based on pointer equality of this field.
 406     pub lint: &'static Lint,
 407 }
 408
 409 impl PartialEq for LintId {
 410     fn eq(&self, other: &LintId) -> bool {
 411         std::ptr::eq(self.lint, other.lint)
 412     }
 413 }
 414
 415 impl Eq for LintId {}
 416
 417 impl std::hash::Hash for LintId {
 418     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 419         let ptr = self.lint as *const Lint;
 420         ptr.hash(state);
 421     }
 422 }
 423
 424 impl LintId {
 425     /// Gets the `LintId` for a `Lint`.
 426     pub fn of(lint: &'static Lint) -> LintId {
 427         LintId { lint }
 428     }
 429
 430     pub fn lint_name_raw(&self) -> &'static str {
 431         self.lint.name
 432     }
 433
 434     /// Gets the name of the lint.
 435     pub fn to_string(&self) -> String {
 436         self.lint.name_lower()
 437     }
 438 }
 439
 440 impl<HCX> HashStable<HCX> for LintId {
 441     #[inline]
 442     fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
 443         self.lint_name_raw().hash_stable(hcx, hasher);
 444     }
 445 }
 446
 447 impl<HCX> ToStableHashKey<HCX> for LintId {
 448     type KeyType = &'static str;
 449
 450     #[inline]
 451     fn to_stable_hash_key(&self, _: &HCX) -> &'static str {
 452         self.lint_name_raw()
 453     }
 454 }
 455
 456 // This could be a closure, but then implementing derive trait
 457 // becomes hacky (and it gets allocated).
 458 #[derive(Debug)]
 459 pub enum BuiltinLintDiagnostics {
 460     Normal,
 461     AbsPathWithModule(Span),
 462     ProcMacroDeriveResolutionFallback(Span),
 463     MacroExpandedMacroExportsAccessedByAbsolutePaths(Span),
 464     ElidedLifetimesInPaths(usize, Span, bool, Span),
 465     UnknownCrateTypes(Span, String, String),
 466     UnusedImports(String, Vec<(Span, String)>, Option<Span>),
 467     RedundantImport(Vec<(Span, bool)>, Ident),
 468     DeprecatedMacro(Option<Symbol>, Span),
 469     MissingAbi(Span, Abi),
 470     UnusedDocComment(Span),
 471     UnusedBuiltinAttribute {
 472         attr_name: Symbol,
 473         macro_name: String,
 474         invoc_span: Span,
 475     },
 476     PatternsInFnsWithoutBody(Span, Ident),
 477     LegacyDeriveHelpers(Span),
 478     ProcMacroBackCompat(String),
 479     OrPatternsBackCompat(Span, String),
 480     ReservedPrefix(Span),
 481     TrailingMacro(bool, Ident),
 482     BreakWithLabelAndLoop(Span),
 483     NamedAsmLabel(String),
 484     UnicodeTextFlow(Span, String),
 485     UnexpectedCfg((Symbol, Span), Option<(Symbol, Span)>),
 486     DeprecatedWhereclauseLocation(Span, String),
 487     SingleUseLifetime {
 488         /// Span of the parameter which declares this lifetime.
 489         param_span: Span,
 490         /// Span of the code that should be removed when eliding this lifetime.
 491         /// This span should include leading or trailing comma.
 492         deletion_span: Span,
 493         /// Span of the single use, or None if the lifetime is never used.
 494         /// If true, the lifetime will be fully elided.
 495         use_span: Option<(Span, bool)>,
 496     },
 497     NamedArgumentUsedPositionally {
 498         /// Span where the named argument is used by position and will be replaced with the named
 499         /// argument name
 500         position_sp_to_replace: Option<Span>,
 501         /// Span where the named argument is used by position and is used for lint messages
 502         position_sp_for_msg: Option<Span>,
 503         /// Span where the named argument's name is (so we know where to put the warning message)
 504         named_arg_sp: Span,
 505         /// String containing the named arguments name
 506         named_arg_name: String,
 507         /// Indicates if the named argument is used as a width/precision for formatting
 508         is_formatting_arg: bool,
 509     },
 510 }
 511
 512 /// Lints that are buffered up early on in the `Session` before the
 513 /// `LintLevels` is calculated.
 514 pub struct BufferedEarlyLint {
 515     /// The span of code that we are linting on.
 516     pub span: MultiSpan,
 517
 518     /// The lint message.
 519     pub msg: DiagnosticMessage,
 520
 521     /// The `NodeId` of the AST node that generated the lint.
 522     pub node_id: NodeId,
 523
 524     /// A lint Id that can be passed to
 525     /// `rustc_lint::early::EarlyContextAndPass::check_id`.
 526     pub lint_id: LintId,
 527
 528     /// Customization of the `DiagnosticBuilder<'_>` for the lint.
 529     pub diagnostic: BuiltinLintDiagnostics,
 530 }
 531
 532 #[derive(Default)]
 533 pub struct LintBuffer {
 534     pub map: NodeMap<Vec<BufferedEarlyLint>>,
 535 }
 536
 537 impl LintBuffer {
 538     pub fn add_early_lint(&mut self, early_lint: BufferedEarlyLint) {
 539         let arr = self.map.entry(early_lint.node_id).or_default();
 540         arr.push(early_lint);
 541     }
 542
 543     pub fn add_lint(
 544         &mut self,
 545         lint: &'static Lint,
 546         node_id: NodeId,
 547         span: MultiSpan,
 548         msg: impl Into<DiagnosticMessage>,
 549         diagnostic: BuiltinLintDiagnostics,
 550     ) {
 551         let lint_id = LintId::of(lint);
 552         let msg = msg.into();
 553         self.add_early_lint(BufferedEarlyLint { lint_id, node_id, span, msg, diagnostic });
 554     }
 555
 556     pub fn take(&mut self, id: NodeId) -> Vec<BufferedEarlyLint> {
 557         self.map.remove(&id).unwrap_or_default()
 558     }
 559
 560     pub fn buffer_lint(
 561         &mut self,
 562         lint: &'static Lint,
 563         id: NodeId,
 564         sp: impl Into<MultiSpan>,
 565         msg: impl Into<DiagnosticMessage>,
 566     ) {
 567         self.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
 568     }
 569
 570     pub fn buffer_lint_with_diagnostic(
 571         &mut self,
 572         lint: &'static Lint,
 573         id: NodeId,
 574         sp: impl Into<MultiSpan>,
 575         msg: impl Into<DiagnosticMessage>,
 576         diagnostic: BuiltinLintDiagnostics,
 577     ) {
 578         self.add_lint(lint, id, sp.into(), msg, diagnostic)
 579     }
 580 }
 581
 582 /// Declares a static item of type `&'static Lint`.
 583 ///
 584 /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html> for
 585 /// documentation and guidelines on writing lints.
 586 ///
 587 /// The macro call should start with a doc comment explaining the lint
 588 /// which will be embedded in the rustc user documentation book. It should
 589 /// be written in markdown and have a format that looks like this:
 590 ///
 591 /// ```rust,ignore (doc-example)
 592 /// /// The `my_lint_name` lint detects [short explanation here].
 593 /// ///
 594 /// /// ### Example
 595 /// ///
 596 /// /// ```rust
 597 /// /// [insert a concise example that triggers the lint]
 598 /// /// ```
 599 /// ///
 600 /// /// {{produces}}
 601 /// ///
 602 /// /// ### Explanation
 603 /// ///
 604 /// /// This should be a detailed explanation of *why* the lint exists,
 605 /// /// and also include suggestions on how the user should fix the problem.
 606 /// /// Try to keep the text simple enough that a beginner can understand,
 607 /// /// and include links to other documentation for terminology that a
 608 /// /// beginner may not be familiar with. If this is "allow" by default,
 609 /// /// it should explain why (are there false positives or other issues?). If
 610 /// /// this is a future-incompatible lint, it should say so, with text that
 611 /// /// looks roughly like this:
 612 /// ///
 613 /// /// This is a [future-incompatible] lint to transition this to a hard
 614 /// /// error in the future. See [issue #xxxxx] for more details.
 615 /// ///
 616 /// /// [issue #xxxxx]: https://github.com/rust-lang/rust/issues/xxxxx
 617 /// ```
 618 ///
 619 /// The `{{produces}}` tag will be automatically replaced with the output from
 620 /// the example by the build system. If the lint example is too complex to run
 621 /// as a simple example (for example, it needs an extern crate), mark the code
 622 /// block with `ignore` and manually replace the `{{produces}}` line with the
 623 /// expected output in a `text` code block.
 624 ///
 625 /// If this is a rustdoc-only lint, then only include a brief introduction
 626 /// with a link with the text `[rustdoc book]` so that the validator knows
 627 /// that this is for rustdoc only (see BROKEN_INTRA_DOC_LINKS as an example).
 628 ///
 629 /// Commands to view and test the documentation:
 630 ///
 631 /// * `./x.py doc --stage=1 src/doc/rustc --open`: Builds the rustc book and opens it.
 632 /// * `./x.py test src/tools/lint-docs`: Validates that the lint docs have the
 633 ///   correct style, and that the code example actually emits the expected
 634 ///   lint.
 635 ///
 636 /// If you have already built the compiler, and you want to make changes to
 637 /// just the doc comments, then use the `--keep-stage=0` flag with the above
 638 /// commands to avoid rebuilding the compiler.
 639 #[macro_export]
 640 macro_rules! declare_lint {
 641     ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr) => (
 642         $crate::declare_lint!(
 643             $(#[$attr])* $vis $NAME, $Level, $desc,
 644         );
 645     );
 646     ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr,
 647      $(@feature_gate = $gate:expr;)?
 648      $(@future_incompatible = FutureIncompatibleInfo { $($field:ident : $val:expr),* $(,)*  }; )?
 649      $($v:ident),*) => (
 650         $(#[$attr])*
 651         $vis static $NAME: &$crate::Lint = &$crate::Lint {
 652             name: stringify!($NAME),
 653             default_level: $crate::$Level,
 654             desc: $desc,
 655             edition_lint_opts: None,
 656             is_plugin: false,
 657             $($v: true,)*
 658             $(feature_gate: Some($gate),)*
 659             $(future_incompatible: Some($crate::FutureIncompatibleInfo {
 660                 $($field: $val,)*
 661                 ..$crate::FutureIncompatibleInfo::default_fields_for_macro()
 662             }),)*
 663             ..$crate::Lint::default_fields_for_macro()
 664         };
 665     );
 666     ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr,
 667      $lint_edition: expr => $edition_level: ident
 668     ) => (
 669         $(#[$attr])*
 670         $vis static $NAME: &$crate::Lint = &$crate::Lint {
 671             name: stringify!($NAME),
 672             default_level: $crate::$Level,
 673             desc: $desc,
 674             edition_lint_opts: Some(($lint_edition, $crate::Level::$edition_level)),
 675             report_in_external_macro: false,
 676             is_plugin: false,
 677         };
 678     );
 679 }
 680
 681 #[macro_export]
 682 macro_rules! declare_tool_lint {
 683     (
 684         $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level: ident, $desc: expr
 685         $(, @feature_gate = $gate:expr;)?
 686     ) => (
 687         $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, false $(, @feature_gate = $gate;)?}
 688     );
 689     (
 690         $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr,
 691         report_in_external_macro: $rep:expr
 692         $(, @feature_gate = $gate:expr;)?
 693     ) => (
 694          $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, $rep $(, @feature_gate = $gate;)?}
 695     );
 696     (
 697         $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr,
 698         $external:expr
 699         $(, @feature_gate = $gate:expr;)?
 700     ) => (
 701         $(#[$attr])*
 702         $vis static $NAME: &$crate::Lint = &$crate::Lint {
 703             name: &concat!(stringify!($tool), "::", stringify!($NAME)),
 704             default_level: $crate::$Level,
 705             desc: $desc,
 706             edition_lint_opts: None,
 707             report_in_external_macro: $external,
 708             future_incompatible: None,
 709             is_plugin: true,
 710             $(feature_gate: Some($gate),)?
 711             crate_level_only: false,
 712             ..$crate::Lint::default_fields_for_macro()
 713         };
 714     );
 715 }
 716
 717 /// Declares a static `LintArray` and return it as an expression.
 718 #[macro_export]
 719 macro_rules! lint_array {
 720     ($( $lint:expr ),* ,) => { lint_array!( $($lint),* ) };
 721     ($( $lint:expr ),*) => {{
 722         vec![$($lint),*]
 723     }}
 724 }
 725
 726 pub type LintArray = Vec<&'static Lint>;
 727
 728 pub trait LintPass {
 729     fn name(&self) -> &'static str;
 730 }
 731
 732 /// Implements `LintPass for $ty` with the given list of `Lint` statics.
 733 #[macro_export]
 734 macro_rules! impl_lint_pass {
 735     ($ty:ty => [$($lint:expr),* $(,)?]) => {
 736         impl $crate::LintPass for $ty {
 737             fn name(&self) -> &'static str { stringify!($ty) }
 738         }
 739         impl $ty {
 740             pub fn get_lints() -> $crate::LintArray { $crate::lint_array!($($lint),*) }
 741         }
 742     };
 743 }
 744
 745 /// Declares a type named `$name` which implements `LintPass`.
 746 /// To the right of `=>` a comma separated list of `Lint` statics is given.
 747 #[macro_export]
 748 macro_rules! declare_lint_pass {
 749     ($(#[$m:meta])* $name:ident => [$($lint:expr),* $(,)?]) => {
 750         $(#[$m])* #[derive(Copy, Clone)] pub struct $name;
 751         $crate::impl_lint_pass!($name => [$($lint),*]);
 752     };
 753 }