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)]
59 rustc_data_structures::impl_stable_hash_via_hash!(Level);
62 /// Converts a level to a lower-case string.
63 pub fn as_str(self) -> &'static str {
65 Level::Allow => "allow",
66 Level::Warn => "warn",
67 Level::ForceWarn => "force-warns",
68 Level::Deny => "deny",
69 Level::Forbid => "forbid",
73 /// Converts a lower-case string to a level.
74 pub fn from_str(x: &str) -> Option<Level> {
76 "allow" => Some(Level::Allow),
77 "warn" => Some(Level::Warn),
78 "deny" => Some(Level::Deny),
79 "forbid" => Some(Level::Forbid),
84 /// Converts a symbol to a level.
85 pub fn from_symbol(x: Symbol) -> Option<Level> {
87 sym::allow => Some(Level::Allow),
88 sym::warn => Some(Level::Warn),
89 sym::deny => Some(Level::Deny),
90 sym::forbid => Some(Level::Forbid),
96 /// Specification of a single lint.
97 #[derive(Copy, Clone, Debug)]
99 /// A string identifier for the lint.
101 /// This identifies the lint in attributes and in command-line arguments.
102 /// In those contexts it is always lowercase, but this field is compared
103 /// in a way which is case-insensitive for ASCII characters. This allows
104 /// `declare_lint!()` invocations to follow the convention of upper-case
105 /// statics without repeating the name.
107 /// The name is written with underscores, e.g., "unused_imports".
108 /// On the command line, underscores become dashes.
110 /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html#lint-naming>
111 /// for naming guidelines.
112 pub name: &'static str,
114 /// Default level for the lint.
116 /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html#diagnostic-levels>
117 /// for guidelines on choosing a default level.
118 pub default_level: Level,
120 /// Description of the lint or the issue it detects.
122 /// e.g., "imports that are never used"
123 pub desc: &'static str,
125 /// Starting at the given edition, default to the given lint level. If this is `None`, then use
127 pub edition_lint_opts: Option<(Edition, Level)>,
129 /// `true` if this lint is reported even inside expansions of external macros.
130 pub report_in_external_macro: bool,
132 pub future_incompatible: Option<FutureIncompatibleInfo>,
136 /// `Some` if this lint is feature gated, otherwise `None`.
137 pub feature_gate: Option<Symbol>,
139 pub crate_level_only: bool,
142 /// Extra information for a future incompatibility lint.
143 #[derive(Copy, Clone, Debug)]
144 pub struct FutureIncompatibleInfo {
145 /// e.g., a URL for an issue/PR/RFC or error code
146 pub reference: &'static str,
147 /// The reason for the lint used by diagnostics to provide
148 /// the right help message
149 pub reason: FutureIncompatibilityReason,
150 /// Whether to explain the reason to the user.
152 /// Set to false for lints that already include a more detailed
154 pub explain_reason: bool,
155 /// Information about a future breakage, which will
156 /// be emitted in JSON messages to be displayed by Cargo
157 /// for upstream deps
158 pub future_breakage: Option<FutureBreakage>,
161 /// The reason for future incompatibility
162 #[derive(Copy, Clone, Debug)]
163 pub enum FutureIncompatibilityReason {
164 /// This will be an error in a future release
167 /// Previously accepted code that will become an
168 /// error in the provided edition
169 EditionError(Edition),
170 /// Code that changes meaning in some way in
171 /// the provided edition
172 EditionSemanticsChange(Edition),
175 impl FutureIncompatibilityReason {
176 pub fn edition(self) -> Option<Edition> {
178 Self::EditionError(e) => Some(e),
179 Self::EditionSemanticsChange(e) => Some(e),
185 #[derive(Copy, Clone, Debug)]
186 pub struct FutureBreakage {
187 pub date: Option<&'static str>,
190 impl FutureIncompatibleInfo {
191 pub const fn default_fields_for_macro() -> Self {
192 FutureIncompatibleInfo {
194 reason: FutureIncompatibilityReason::FutureReleaseError,
195 explain_reason: true,
196 future_breakage: None,
202 pub const fn default_fields_for_macro() -> Self {
205 default_level: Level::Forbid,
207 edition_lint_opts: None,
209 report_in_external_macro: false,
210 future_incompatible: None,
212 crate_level_only: false,
216 /// Gets the lint's name, with ASCII letters converted to lowercase.
217 pub fn name_lower(&self) -> String {
218 self.name.to_ascii_lowercase()
221 pub fn default_level(&self, edition: Edition) -> Level {
222 self.edition_lint_opts
223 .filter(|(e, _)| *e <= edition)
225 .unwrap_or(self.default_level)
229 /// Identifies a lint known to the compiler.
230 #[derive(Clone, Copy, Debug)]
232 // Identity is based on pointer equality of this field.
233 pub lint: &'static Lint,
236 impl PartialEq for LintId {
237 fn eq(&self, other: &LintId) -> bool {
238 std::ptr::eq(self.lint, other.lint)
242 impl Eq for LintId {}
244 impl std::hash::Hash for LintId {
245 fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
246 let ptr = self.lint as *const Lint;
252 /// Gets the `LintId` for a `Lint`.
253 pub fn of(lint: &'static Lint) -> LintId {
257 pub fn lint_name_raw(&self) -> &'static str {
261 /// Gets the name of the lint.
262 pub fn to_string(&self) -> String {
263 self.lint.name_lower()
267 impl<HCX> HashStable<HCX> for LintId {
269 fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
270 self.lint_name_raw().hash_stable(hcx, hasher);
274 impl<HCX> ToStableHashKey<HCX> for LintId {
275 type KeyType = &'static str;
278 fn to_stable_hash_key(&self, _: &HCX) -> &'static str {
283 // Duplicated from rustc_session::config::ExternDepSpec to avoid cyclic dependency
285 pub enum ExternDepSpec {
290 // This could be a closure, but then implementing derive trait
291 // becomes hacky (and it gets allocated).
293 pub enum BuiltinLintDiagnostics {
295 BareTraitObject(Span, /* is_global */ bool),
296 AbsPathWithModule(Span),
297 ProcMacroDeriveResolutionFallback(Span),
298 MacroExpandedMacroExportsAccessedByAbsolutePaths(Span),
299 ElidedLifetimesInPaths(usize, Span, bool, Span, String),
300 UnknownCrateTypes(Span, String, String),
301 UnusedImports(String, Vec<(Span, String)>),
302 RedundantImport(Vec<(Span, bool)>, Ident),
303 DeprecatedMacro(Option<Symbol>, Span),
304 MissingAbi(Span, Abi),
305 UnusedDocComment(Span),
306 PatternsInFnsWithoutBody(Span, Ident),
307 LegacyDeriveHelpers(Span),
308 ExternDepSpec(String, ExternDepSpec),
309 ProcMacroBackCompat(String),
310 OrPatternsBackCompat(Span, String),
311 ReservedPrefix(Span),
314 /// Lints that are buffered up early on in the `Session` before the
315 /// `LintLevels` is calculated.
317 pub struct BufferedEarlyLint {
318 /// The span of code that we are linting on.
321 /// The lint message.
324 /// The `NodeId` of the AST node that generated the lint.
327 /// A lint Id that can be passed to
328 /// `rustc_lint::early::EarlyContextAndPass::check_id`.
331 /// Customization of the `DiagnosticBuilder<'_>` for the lint.
332 pub diagnostic: BuiltinLintDiagnostics,
336 pub struct LintBuffer {
337 pub map: NodeMap<Vec<BufferedEarlyLint>>,
341 pub fn add_early_lint(&mut self, early_lint: BufferedEarlyLint) {
342 let arr = self.map.entry(early_lint.node_id).or_default();
343 if !arr.contains(&early_lint) {
344 arr.push(early_lint);
354 diagnostic: BuiltinLintDiagnostics,
356 let lint_id = LintId::of(lint);
357 let msg = msg.to_string();
358 self.add_early_lint(BufferedEarlyLint { lint_id, node_id, span, msg, diagnostic });
361 pub fn take(&mut self, id: NodeId) -> Vec<BufferedEarlyLint> {
362 self.map.remove(&id).unwrap_or_default()
369 sp: impl Into<MultiSpan>,
372 self.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
375 pub fn buffer_lint_with_diagnostic(
379 sp: impl Into<MultiSpan>,
381 diagnostic: BuiltinLintDiagnostics,
383 self.add_lint(lint, id, sp.into(), msg, diagnostic)
387 /// Declares a static item of type `&'static Lint`.
389 /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html> for
390 /// documentation and guidelines on writing lints.
392 /// The macro call should start with a doc comment explaining the lint
393 /// which will be embedded in the rustc user documentation book. It should
394 /// be written in markdown and have a format that looks like this:
396 /// ```rust,ignore (doc-example)
397 /// /// The `my_lint_name` lint detects [short explanation here].
402 /// /// [insert a concise example that triggers the lint]
407 /// /// ### Explanation
409 /// /// This should be a detailed explanation of *why* the lint exists,
410 /// /// and also include suggestions on how the user should fix the problem.
411 /// /// Try to keep the text simple enough that a beginner can understand,
412 /// /// and include links to other documentation for terminology that a
413 /// /// beginner may not be familiar with. If this is "allow" by default,
414 /// /// it should explain why (are there false positives or other issues?). If
415 /// /// this is a future-incompatible lint, it should say so, with text that
416 /// /// looks roughly like this:
418 /// /// This is a [future-incompatible] lint to transition this to a hard
419 /// /// error in the future. See [issue #xxxxx] for more details.
421 /// /// [issue #xxxxx]: https://github.com/rust-lang/rust/issues/xxxxx
424 /// The `{{produces}}` tag will be automatically replaced with the output from
425 /// the example by the build system. If the lint example is too complex to run
426 /// as a simple example (for example, it needs an extern crate), mark the code
427 /// block with `ignore` and manually replace the `{{produces}}` line with the
428 /// expected output in a `text` code block.
430 /// If this is a rustdoc-only lint, then only include a brief introduction
431 /// with a link with the text `[rustdoc book]` so that the validator knows
432 /// that this is for rustdoc only (see BROKEN_INTRA_DOC_LINKS as an example).
434 /// Commands to view and test the documentation:
436 /// * `./x.py doc --stage=1 src/doc/rustc --open`: Builds the rustc book and opens it.
437 /// * `./x.py test src/tools/lint-docs`: Validates that the lint docs have the
438 /// correct style, and that the code example actually emits the expected
441 /// If you have already built the compiler, and you want to make changes to
442 /// just the doc comments, then use the `--keep-stage=0` flag with the above
443 /// commands to avoid rebuilding the compiler.
445 macro_rules! declare_lint {
446 ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr) => (
447 $crate::declare_lint!(
448 $(#[$attr])* $vis $NAME, $Level, $desc,
451 ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr,
452 $(@feature_gate = $gate:expr;)?
453 $(@future_incompatible = FutureIncompatibleInfo { $($field:ident : $val:expr),* $(,)* }; )?
456 $vis static $NAME: &$crate::Lint = &$crate::Lint {
457 name: stringify!($NAME),
458 default_level: $crate::$Level,
460 edition_lint_opts: None,
463 $(feature_gate: Some($gate),)*
464 $(future_incompatible: Some($crate::FutureIncompatibleInfo {
466 ..$crate::FutureIncompatibleInfo::default_fields_for_macro()
468 ..$crate::Lint::default_fields_for_macro()
471 ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr,
472 $lint_edition: expr => $edition_level: ident
475 $vis static $NAME: &$crate::Lint = &$crate::Lint {
476 name: stringify!($NAME),
477 default_level: $crate::$Level,
479 edition_lint_opts: Some(($lint_edition, $crate::Level::$edition_level)),
480 report_in_external_macro: false,
487 macro_rules! declare_tool_lint {
489 $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level: ident, $desc: expr
491 $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, false}
494 $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr,
495 report_in_external_macro: $rep:expr
497 $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, $rep}
500 $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr,
504 $vis static $NAME: &$crate::Lint = &$crate::Lint {
505 name: &concat!(stringify!($tool), "::", stringify!($NAME)),
506 default_level: $crate::$Level,
508 edition_lint_opts: None,
509 report_in_external_macro: $external,
510 future_incompatible: None,
513 crate_level_only: false,
518 /// Declares a static `LintArray` and return it as an expression.
520 macro_rules! lint_array {
521 ($( $lint:expr ),* ,) => { lint_array!( $($lint),* ) };
522 ($( $lint:expr ),*) => {{
527 pub type LintArray = Vec<&'static Lint>;
530 fn name(&self) -> &'static str;
533 /// Implements `LintPass for $ty` with the given list of `Lint` statics.
535 macro_rules! impl_lint_pass {
536 ($ty:ty => [$($lint:expr),* $(,)?]) => {
537 impl $crate::LintPass for $ty {
538 fn name(&self) -> &'static str { stringify!($ty) }
541 pub fn get_lints() -> $crate::LintArray { $crate::lint_array!($($lint),*) }
546 /// Declares a type named `$name` which implements `LintPass`.
547 /// To the right of `=>` a comma separated list of `Lint` statics is given.
549 macro_rules! declare_lint_pass {
550 ($(#[$m:meta])* $name:ident => [$($lint:expr),* $(,)?]) => {
551 $(#[$m])* #[derive(Copy, Clone)] pub struct $name;
552 $crate::impl_lint_pass!($name => [$($lint),*]);