2 extern crate rustc_macros;
4 pub use self::Level::*;
5 use rustc_ast::node_id::{NodeId, NodeMap};
6 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
7 use rustc_serialize::json::Json;
8 use rustc_span::edition::Edition;
9 use rustc_span::{sym, symbol::Ident, MultiSpan, Span, Symbol};
10 use rustc_target::spec::abi::Abi;
15 macro_rules! pluralize {
17 if $x != 1 { "s" } else { "" }
21 /// Indicates the confidence in the correctness of a suggestion.
23 /// All suggestions are marked with an `Applicability`. Tools use the applicability of a suggestion
24 /// to determine whether it should be automatically applied or if the user should be consulted
25 /// before applying the suggestion.
26 #[derive(Copy, Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
27 pub enum Applicability {
28 /// The suggestion is definitely what the user intended, or maintains the exact meaning of the code.
29 /// This suggestion should be automatically applied.
31 /// In case of multiple `MachineApplicable` suggestions (whether as part of
32 /// the same `multipart_suggestion` or not), all of them should be
33 /// automatically applied.
36 /// The suggestion may be what the user intended, but it is uncertain. The suggestion should
37 /// result in valid Rust code if it is applied.
40 /// The suggestion contains placeholders like `(...)` or `{ /* fields */ }`. The suggestion
41 /// cannot be applied automatically because it will not result in valid Rust code. The user
42 /// will need to fill in the placeholders.
45 /// The applicability of the suggestion is unknown.
49 /// Setting for how to handle a lint.
50 #[derive(Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Debug, Hash)]
58 rustc_data_structures::impl_stable_hash_via_hash!(Level);
61 /// Converts a level to a lower-case string.
62 pub fn as_str(self) -> &'static str {
64 Level::Allow => "allow",
65 Level::Warn => "warn",
66 Level::Deny => "deny",
67 Level::Forbid => "forbid",
71 /// Converts a lower-case string to a level.
72 pub fn from_str(x: &str) -> Option<Level> {
74 "allow" => Some(Level::Allow),
75 "warn" => Some(Level::Warn),
76 "deny" => Some(Level::Deny),
77 "forbid" => Some(Level::Forbid),
82 /// Converts a symbol to a level.
83 pub fn from_symbol(x: Symbol) -> Option<Level> {
85 sym::allow => Some(Level::Allow),
86 sym::warn => Some(Level::Warn),
87 sym::deny => Some(Level::Deny),
88 sym::forbid => Some(Level::Forbid),
94 /// Specification of a single lint.
95 #[derive(Copy, Clone, Debug)]
97 /// A string identifier for the lint.
99 /// This identifies the lint in attributes and in command-line arguments.
100 /// In those contexts it is always lowercase, but this field is compared
101 /// in a way which is case-insensitive for ASCII characters. This allows
102 /// `declare_lint!()` invocations to follow the convention of upper-case
103 /// statics without repeating the name.
105 /// The name is written with underscores, e.g., "unused_imports".
106 /// On the command line, underscores become dashes.
108 /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html#lint-naming>
109 /// for naming guidelines.
110 pub name: &'static str,
112 /// Default level for the lint.
114 /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html#diagnostic-levels>
115 /// for guidelines on choosing a default level.
116 pub default_level: Level,
118 /// Description of the lint or the issue it detects.
120 /// e.g., "imports that are never used"
121 pub desc: &'static str,
123 /// Starting at the given edition, default to the given lint level. If this is `None`, then use
125 pub edition_lint_opts: Option<(Edition, Level)>,
127 /// `true` if this lint is reported even inside expansions of external macros.
128 pub report_in_external_macro: bool,
130 pub future_incompatible: Option<FutureIncompatibleInfo>,
134 /// `Some` if this lint is feature gated, otherwise `None`.
135 pub feature_gate: Option<Symbol>,
137 pub crate_level_only: bool,
140 /// Extra information for a future incompatibility lint.
141 #[derive(Copy, Clone, Debug)]
142 pub struct FutureIncompatibleInfo {
143 /// e.g., a URL for an issue/PR/RFC or error code
144 pub reference: &'static str,
145 /// The reason for the lint used by diagnostics to provide
146 /// the right help message
147 pub reason: FutureIncompatibilityReason,
148 /// Information about a future breakage, which will
149 /// be emitted in JSON messages to be displayed by Cargo
150 /// for upstream deps
151 pub future_breakage: Option<FutureBreakage>,
154 /// The reason for future incompatibility
155 #[derive(Copy, Clone, Debug)]
156 pub enum FutureIncompatibilityReason {
157 /// This will be an error in a future release
160 /// Previously accepted code that will become an
161 /// error in the provided edition
162 EditionError(Edition),
163 /// Code that changes meaning in some way in
164 /// the provided edition
165 EditionSemanticsChange(Edition),
168 impl FutureIncompatibilityReason {
169 pub fn edition(self) -> Option<Edition> {
171 Self::EditionError(e) => Some(e),
172 Self::EditionSemanticsChange(e) => Some(e),
178 #[derive(Copy, Clone, Debug)]
179 pub struct FutureBreakage {
180 pub date: Option<&'static str>,
183 impl FutureIncompatibleInfo {
184 pub const fn default_fields_for_macro() -> Self {
185 FutureIncompatibleInfo {
187 reason: FutureIncompatibilityReason::FutureReleaseError,
188 future_breakage: None,
194 pub const fn default_fields_for_macro() -> Self {
197 default_level: Level::Forbid,
199 edition_lint_opts: None,
201 report_in_external_macro: false,
202 future_incompatible: None,
204 crate_level_only: false,
208 /// Gets the lint's name, with ASCII letters converted to lowercase.
209 pub fn name_lower(&self) -> String {
210 self.name.to_ascii_lowercase()
213 pub fn default_level(&self, edition: Edition) -> Level {
214 self.edition_lint_opts
215 .filter(|(e, _)| *e <= edition)
217 .unwrap_or(self.default_level)
221 /// Identifies a lint known to the compiler.
222 #[derive(Clone, Copy, Debug)]
224 // Identity is based on pointer equality of this field.
225 pub lint: &'static Lint,
228 impl PartialEq for LintId {
229 fn eq(&self, other: &LintId) -> bool {
230 std::ptr::eq(self.lint, other.lint)
234 impl Eq for LintId {}
236 impl std::hash::Hash for LintId {
237 fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
238 let ptr = self.lint as *const Lint;
244 /// Gets the `LintId` for a `Lint`.
245 pub fn of(lint: &'static Lint) -> LintId {
249 pub fn lint_name_raw(&self) -> &'static str {
253 /// Gets the name of the lint.
254 pub fn to_string(&self) -> String {
255 self.lint.name_lower()
259 impl<HCX> HashStable<HCX> for LintId {
261 fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
262 self.lint_name_raw().hash_stable(hcx, hasher);
266 impl<HCX> ToStableHashKey<HCX> for LintId {
267 type KeyType = &'static str;
270 fn to_stable_hash_key(&self, _: &HCX) -> &'static str {
275 // Duplicated from rustc_session::config::ExternDepSpec to avoid cyclic dependency
277 pub enum ExternDepSpec {
282 // This could be a closure, but then implementing derive trait
283 // becomes hacky (and it gets allocated).
285 pub enum BuiltinLintDiagnostics {
287 BareTraitObject(Span, /* is_global */ bool),
288 AbsPathWithModule(Span),
289 ProcMacroDeriveResolutionFallback(Span),
290 MacroExpandedMacroExportsAccessedByAbsolutePaths(Span),
291 ElidedLifetimesInPaths(usize, Span, bool, Span, String),
292 UnknownCrateTypes(Span, String, String),
293 UnusedImports(String, Vec<(Span, String)>),
294 RedundantImport(Vec<(Span, bool)>, Ident),
295 DeprecatedMacro(Option<Symbol>, Span),
296 MissingAbi(Span, Abi),
297 UnusedDocComment(Span),
298 PatternsInFnsWithoutBody(Span, Ident),
299 LegacyDeriveHelpers(Span),
300 ExternDepSpec(String, ExternDepSpec),
301 ProcMacroBackCompat(String),
302 OrPatternsBackCompat(Span, String),
303 ReservedPrefix(Span),
306 /// Lints that are buffered up early on in the `Session` before the
307 /// `LintLevels` is calculated.
309 pub struct BufferedEarlyLint {
310 /// The span of code that we are linting on.
313 /// The lint message.
316 /// The `NodeId` of the AST node that generated the lint.
319 /// A lint Id that can be passed to
320 /// `rustc_lint::early::EarlyContextAndPass::check_id`.
323 /// Customization of the `DiagnosticBuilder<'_>` for the lint.
324 pub diagnostic: BuiltinLintDiagnostics,
328 pub struct LintBuffer {
329 pub map: NodeMap<Vec<BufferedEarlyLint>>,
333 pub fn add_early_lint(&mut self, early_lint: BufferedEarlyLint) {
334 let arr = self.map.entry(early_lint.node_id).or_default();
335 if !arr.contains(&early_lint) {
336 arr.push(early_lint);
346 diagnostic: BuiltinLintDiagnostics,
348 let lint_id = LintId::of(lint);
349 let msg = msg.to_string();
350 self.add_early_lint(BufferedEarlyLint { lint_id, node_id, span, msg, diagnostic });
353 pub fn take(&mut self, id: NodeId) -> Vec<BufferedEarlyLint> {
354 self.map.remove(&id).unwrap_or_default()
361 sp: impl Into<MultiSpan>,
364 self.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
367 pub fn buffer_lint_with_diagnostic(
371 sp: impl Into<MultiSpan>,
373 diagnostic: BuiltinLintDiagnostics,
375 self.add_lint(lint, id, sp.into(), msg, diagnostic)
379 /// Declares a static item of type `&'static Lint`.
381 /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html> for
382 /// documentation and guidelines on writing lints.
384 /// The macro call should start with a doc comment explaining the lint
385 /// which will be embedded in the rustc user documentation book. It should
386 /// be written in markdown and have a format that looks like this:
388 /// ```rust,ignore (doc-example)
389 /// /// The `my_lint_name` lint detects [short explanation here].
394 /// /// [insert a concise example that triggers the lint]
399 /// /// ### Explanation
401 /// /// This should be a detailed explanation of *why* the lint exists,
402 /// /// and also include suggestions on how the user should fix the problem.
403 /// /// Try to keep the text simple enough that a beginner can understand,
404 /// /// and include links to other documentation for terminology that a
405 /// /// beginner may not be familiar with. If this is "allow" by default,
406 /// /// it should explain why (are there false positives or other issues?). If
407 /// /// this is a future-incompatible lint, it should say so, with text that
408 /// /// looks roughly like this:
410 /// /// This is a [future-incompatible] lint to transition this to a hard
411 /// /// error in the future. See [issue #xxxxx] for more details.
413 /// /// [issue #xxxxx]: https://github.com/rust-lang/rust/issues/xxxxx
416 /// The `{{produces}}` tag will be automatically replaced with the output from
417 /// the example by the build system. If the lint example is too complex to run
418 /// as a simple example (for example, it needs an extern crate), mark the code
419 /// block with `ignore` and manually replace the `{{produces}}` line with the
420 /// expected output in a `text` code block.
422 /// If this is a rustdoc-only lint, then only include a brief introduction
423 /// with a link with the text `[rustdoc book]` so that the validator knows
424 /// that this is for rustdoc only (see BROKEN_INTRA_DOC_LINKS as an example).
426 /// Commands to view and test the documentation:
428 /// * `./x.py doc --stage=1 src/doc/rustc --open`: Builds the rustc book and opens it.
429 /// * `./x.py test src/tools/lint-docs`: Validates that the lint docs have the
430 /// correct style, and that the code example actually emits the expected
433 /// If you have already built the compiler, and you want to make changes to
434 /// just the doc comments, then use the `--keep-stage=0` flag with the above
435 /// commands to avoid rebuilding the compiler.
437 macro_rules! declare_lint {
438 ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr) => (
439 $crate::declare_lint!(
440 $(#[$attr])* $vis $NAME, $Level, $desc,
443 ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr,
444 $(@feature_gate = $gate:expr;)?
445 $(@future_incompatible = FutureIncompatibleInfo { $($field:ident : $val:expr),* $(,)* }; )?
448 $vis static $NAME: &$crate::Lint = &$crate::Lint {
449 name: stringify!($NAME),
450 default_level: $crate::$Level,
452 edition_lint_opts: None,
455 $(feature_gate: Some($gate),)*
456 $(future_incompatible: Some($crate::FutureIncompatibleInfo {
458 ..$crate::FutureIncompatibleInfo::default_fields_for_macro()
460 ..$crate::Lint::default_fields_for_macro()
463 ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr,
464 $lint_edition: expr => $edition_level: ident
467 $vis static $NAME: &$crate::Lint = &$crate::Lint {
468 name: stringify!($NAME),
469 default_level: $crate::$Level,
471 edition_lint_opts: Some(($lint_edition, $crate::Level::$edition_level)),
472 report_in_external_macro: false,
479 macro_rules! declare_tool_lint {
481 $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level: ident, $desc: expr
483 $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, false}
486 $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr,
487 report_in_external_macro: $rep:expr
489 $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, $rep}
492 $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr,
496 $vis static $NAME: &$crate::Lint = &$crate::Lint {
497 name: &concat!(stringify!($tool), "::", stringify!($NAME)),
498 default_level: $crate::$Level,
500 edition_lint_opts: None,
501 report_in_external_macro: $external,
502 future_incompatible: None,
505 crate_level_only: false,
510 /// Declares a static `LintArray` and return it as an expression.
512 macro_rules! lint_array {
513 ($( $lint:expr ),* ,) => { lint_array!( $($lint),* ) };
514 ($( $lint:expr ),*) => {{
519 pub type LintArray = Vec<&'static Lint>;
522 fn name(&self) -> &'static str;
525 /// Implements `LintPass for $ty` with the given list of `Lint` statics.
527 macro_rules! impl_lint_pass {
528 ($ty:ty => [$($lint:expr),* $(,)?]) => {
529 impl $crate::LintPass for $ty {
530 fn name(&self) -> &'static str { stringify!($ty) }
533 pub fn get_lints() -> $crate::LintArray { $crate::lint_array!($($lint),*) }
538 /// Declares a type named `$name` which implements `LintPass`.
539 /// To the right of `=>` a comma separated list of `Lint` statics is given.
541 macro_rules! declare_lint_pass {
542 ($(#[$m:meta])* $name:ident => [$($lint:expr),* $(,)?]) => {
543 $(#[$m])* #[derive(Copy, Clone)] pub struct $name;
544 $crate::impl_lint_pass!($name => [$($lint),*]);