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#[macro_use] extern crate rustc_macros; pub use self::Level::*; use rustc_ast::node_id::{NodeId, NodeMap}; use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey}; use rustc_span::edition::Edition; use rustc_span::{sym, symbol::Ident, MultiSpan, Span, Symbol}; pub mod builtin; #[macro_export] macro_rules! pluralize { ($x:expr) => { if $x != 1 { "s" } else { "" } }; } /// Indicates the confidence in the correctness of a suggestion. /// /// All suggestions are marked with an `Applicability`. Tools use the applicability of a suggestion /// to determine whether it should be automatically applied or if the user should be consulted /// before applying the suggestion. #[derive(Copy, Clone, Debug, PartialEq, Hash, Encodable, Decodable)] pub enum Applicability { /// The suggestion is definitely what the user intended. This suggestion should be /// automatically applied. MachineApplicable, /// The suggestion may be what the user intended, but it is uncertain. The suggestion should /// result in valid Rust code if it is applied. MaybeIncorrect, /// The suggestion contains placeholders like `(...)` or `{ /* fields */ }`. The suggestion /// cannot be applied automatically because it will not result in valid Rust code. The user /// will need to fill in the placeholders. HasPlaceholders, /// The applicability of the suggestion is unknown. Unspecified, } /// Setting for how to handle a lint. #[derive(Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Debug, Hash)] pub enum Level { Allow, Warn, Deny, Forbid, } rustc_data_structures::impl_stable_hash_via_hash!(Level); impl Level { /// Converts a level to a lower-case string. pub fn as_str(self) -> &'static str { match self { Level::Allow => "allow", Level::Warn => "warn", Level::Deny => "deny", Level::Forbid => "forbid", } } /// Converts a lower-case string to a level. pub fn from_str(x: &str) -> Option<Level> { match x { "allow" => Some(Level::Allow), "warn" => Some(Level::Warn), "deny" => Some(Level::Deny), "forbid" => Some(Level::Forbid), _ => None, } } /// Converts a symbol to a level. pub fn from_symbol(x: Symbol) -> Option<Level> { match x { sym::allow => Some(Level::Allow), sym::warn => Some(Level::Warn), sym::deny => Some(Level::Deny), sym::forbid => Some(Level::Forbid), _ => None, } } } /// Specification of a single lint. #[derive(Copy, Clone, Debug)] pub struct Lint { /// A string identifier for the lint. /// /// This identifies the lint in attributes and in command-line arguments. /// In those contexts it is always lowercase, but this field is compared /// in a way which is case-insensitive for ASCII characters. This allows /// `declare_lint!()` invocations to follow the convention of upper-case /// statics without repeating the name. /// /// The name is written with underscores, e.g., "unused_imports". /// On the command line, underscores become dashes. /// /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html#lint-naming> /// for naming guidelines. pub name: &'static str, /// Default level for the lint. /// /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html#diagnostic-levels> /// for guidelines on choosing a default level. pub default_level: Level, /// Description of the lint or the issue it detects. /// /// e.g., "imports that are never used" pub desc: &'static str, /// Starting at the given edition, default to the given lint level. If this is `None`, then use /// `default_level`. pub edition_lint_opts: Option<(Edition, Level)>, /// `true` if this lint is reported even inside expansions of external macros. pub report_in_external_macro: bool, pub future_incompatible: Option<FutureIncompatibleInfo>, pub is_plugin: bool, /// `Some` if this lint is feature gated, otherwise `None`. pub feature_gate: Option<Symbol>, pub crate_level_only: bool, } /// Extra information for a future incompatibility lint. #[derive(Copy, Clone, Debug)] pub struct FutureIncompatibleInfo { /// e.g., a URL for an issue/PR/RFC or error code pub reference: &'static str, /// If this is an edition fixing lint, the edition in which /// this lint becomes obsolete pub edition: Option<Edition>, /// Information about a future breakage, which will /// be emitted in JSON messages to be displayed by Cargo /// for upstream deps pub future_breakage: Option<FutureBreakage>, } #[derive(Copy, Clone, Debug)] pub struct FutureBreakage { pub date: Option<&'static str>, } impl FutureIncompatibleInfo { pub const fn default_fields_for_macro() -> Self { FutureIncompatibleInfo { reference: "", edition: None, future_breakage: None } } } impl Lint { pub const fn default_fields_for_macro() -> Self { Lint { name: "", default_level: Level::Forbid, desc: "", edition_lint_opts: None, is_plugin: false, report_in_external_macro: false, future_incompatible: None, feature_gate: None, crate_level_only: false, } } /// Gets the lint's name, with ASCII letters converted to lowercase. pub fn name_lower(&self) -> String { self.name.to_ascii_lowercase() } pub fn default_level(&self, edition: Edition) -> Level { self.edition_lint_opts .filter(|(e, _)| *e <= edition) .map(|(_, l)| l) .unwrap_or(self.default_level) } } /// Identifies a lint known to the compiler. #[derive(Clone, Copy, Debug)] pub struct LintId { // Identity is based on pointer equality of this field. pub lint: &'static Lint, } impl PartialEq for LintId { fn eq(&self, other: &LintId) -> bool { std::ptr::eq(self.lint, other.lint) } } impl Eq for LintId {} impl std::hash::Hash for LintId { fn hash<H: std::hash::Hasher>(&self, state: &mut H) { let ptr = self.lint as *const Lint; ptr.hash(state); } } impl LintId { /// Gets the `LintId` for a `Lint`. pub fn of(lint: &'static Lint) -> LintId { LintId { lint } } pub fn lint_name_raw(&self) -> &'static str { self.lint.name } /// Gets the name of the lint. pub fn to_string(&self) -> String { self.lint.name_lower() } } impl<HCX> HashStable<HCX> for LintId { #[inline] fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) { self.lint_name_raw().hash_stable(hcx, hasher); } } impl<HCX> ToStableHashKey<HCX> for LintId { type KeyType = &'static str; #[inline] fn to_stable_hash_key(&self, _: &HCX) -> &'static str { self.lint_name_raw() } } // This could be a closure, but then implementing derive trait // becomes hacky (and it gets allocated). #[derive(PartialEq)] pub enum BuiltinLintDiagnostics { Normal, BareTraitObject(Span, /* is_global */ bool), AbsPathWithModule(Span), ProcMacroDeriveResolutionFallback(Span), MacroExpandedMacroExportsAccessedByAbsolutePaths(Span), ElidedLifetimesInPaths(usize, Span, bool, Span, String), UnknownCrateTypes(Span, String, String), UnusedImports(String, Vec<(Span, String)>), RedundantImport(Vec<(Span, bool)>, Ident), DeprecatedMacro(Option<Symbol>, Span), UnusedDocComment(Span), } /// Lints that are buffered up early on in the `Session` before the /// `LintLevels` is calculated. #[derive(PartialEq)] pub struct BufferedEarlyLint { /// The span of code that we are linting on. pub span: MultiSpan, /// The lint message. pub msg: String, /// The `NodeId` of the AST node that generated the lint. pub node_id: NodeId, /// A lint Id that can be passed to /// `rustc_lint::early::EarlyContextAndPass::check_id`. pub lint_id: LintId, /// Customization of the `DiagnosticBuilder<'_>` for the lint. pub diagnostic: BuiltinLintDiagnostics, } #[derive(Default)] pub struct LintBuffer { pub map: NodeMap<Vec<BufferedEarlyLint>>, } impl LintBuffer { pub fn add_early_lint(&mut self, early_lint: BufferedEarlyLint) { let arr = self.map.entry(early_lint.node_id).or_default(); if !arr.contains(&early_lint) { arr.push(early_lint); } } pub fn add_lint( &mut self, lint: &'static Lint, node_id: NodeId, span: MultiSpan, msg: &str, diagnostic: BuiltinLintDiagnostics, ) { let lint_id = LintId::of(lint); let msg = msg.to_string(); self.add_early_lint(BufferedEarlyLint { lint_id, node_id, span, msg, diagnostic }); } pub fn take(&mut self, id: NodeId) -> Vec<BufferedEarlyLint> { self.map.remove(&id).unwrap_or_default() } pub fn buffer_lint( &mut self, lint: &'static Lint, id: NodeId, sp: impl Into<MultiSpan>, msg: &str, ) { self.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal) } pub fn buffer_lint_with_diagnostic( &mut self, lint: &'static Lint, id: NodeId, sp: impl Into<MultiSpan>, msg: &str, diagnostic: BuiltinLintDiagnostics, ) { self.add_lint(lint, id, sp.into(), msg, diagnostic) } } /// Declares a static item of type `&'static Lint`. /// /// See <https://rustc-dev-guide.rust-lang.org/diagnostics.html> for /// documentation and guidelines on writing lints. /// /// The macro call should start with a doc comment explaining the lint /// which will be embedded in the rustc user documentation book. It should /// be written in markdown and have a format that looks like this: /// /// ```rust,ignore (doc-example) /// /// The `my_lint_name` lint detects [short explanation here]. /// /// /// /// ### Example /// /// /// /// ```rust /// /// [insert a concise example that triggers the lint] /// /// ``` /// /// /// /// {{produces}} /// /// /// /// ### Explanation /// /// /// /// This should be a detailed explanation of *why* the lint exists, /// /// and also include suggestions on how the user should fix the problem. /// /// Try to keep the text simple enough that a beginner can understand, /// /// and include links to other documentation for terminology that a /// /// beginner may not be familiar with. If this is "allow" by default, /// /// it should explain why (are there false positives or other issues?). If /// /// this is a future-incompatible lint, it should say so, with text that /// /// looks roughly like this: /// /// /// /// This is a [future-incompatible] lint to transition this to a hard /// /// error in the future. See [issue #xxxxx] for more details. /// /// /// /// [issue #xxxxx]: https://github.com/rust-lang/rust/issues/xxxxx /// ``` /// /// The `{{produces}}` tag will be automatically replaced with the output from /// the example by the build system. If the lint example is too complex to run /// as a simple example (for example, it needs an extern crate), mark the code /// block with `ignore` and manually replace the `{{produces}}` line with the /// expected output in a `text` code block. /// /// If this is a rustdoc-only lint, then only include a brief introduction /// with a link with the text `[rustdoc book]` so that the validator knows /// that this is for rustdoc only (see BROKEN_INTRA_DOC_LINKS as an example). /// /// Commands to view and test the documentation: /// /// * `./x.py doc --stage=1 src/doc/rustc --open`: Builds the rustc book and opens it. /// * `./x.py test src/tools/lint-docs`: Validates that the lint docs have the /// correct style, and that the code example actually emits the expected /// lint. /// /// If you have already built the compiler, and you want to make changes to /// just the doc comments, then use the `--keep-stage=0` flag with the above /// commands to avoid rebuilding the compiler. #[macro_export] macro_rules! declare_lint { ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr) => ( $crate::declare_lint!( $(#[$attr])* $vis $NAME, $Level, $desc, ); ); ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr, $(@feature_gate = $gate:expr;)? $(@future_incompatible = FutureIncompatibleInfo { $($field:ident : $val:expr),* $(,)* }; )? $($v:ident),*) => ( $(#[$attr])* $vis static $NAME: &$crate::Lint = &$crate::Lint { name: stringify!($NAME), default_level: $crate::$Level, desc: $desc, edition_lint_opts: None, is_plugin: false, $($v: true,)* $(feature_gate: Some($gate),)* $(future_incompatible: Some($crate::FutureIncompatibleInfo { $($field: $val,)* ..$crate::FutureIncompatibleInfo::default_fields_for_macro() }),)* ..$crate::Lint::default_fields_for_macro() }; ); ($(#[$attr:meta])* $vis: vis $NAME: ident, $Level: ident, $desc: expr, $lint_edition: expr => $edition_level: ident ) => ( $(#[$attr])* $vis static $NAME: &$crate::Lint = &$crate::Lint { name: stringify!($NAME), default_level: $crate::$Level, desc: $desc, edition_lint_opts: Some(($lint_edition, $crate::Level::$edition_level)), report_in_external_macro: false, is_plugin: false, }; ); } #[macro_export] macro_rules! declare_tool_lint { ( $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level: ident, $desc: expr ) => ( $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, false} ); ( $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr, report_in_external_macro: $rep:expr ) => ( $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, $rep} ); ( $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr, $external:expr ) => ( $(#[$attr])* $vis static $NAME: &$crate::Lint = &$crate::Lint { name: &concat!(stringify!($tool), "::", stringify!($NAME)), default_level: $crate::$Level, desc: $desc, edition_lint_opts: None, report_in_external_macro: $external, future_incompatible: None, is_plugin: true, feature_gate: None, crate_level_only: false, }; ); } /// Declares a static `LintArray` and return it as an expression. #[macro_export] macro_rules! lint_array { ($( $lint:expr ),* ,) => { lint_array!( $($lint),* ) }; ($( $lint:expr ),*) => {{ vec![$($lint),*] }} } pub type LintArray = Vec<&'static Lint>; pub trait LintPass { fn name(&self) -> &'static str; } /// Implements `LintPass for $ty` with the given list of `Lint` statics. #[macro_export] macro_rules! impl_lint_pass { ($ty:ty => [$($lint:expr),* $(,)?]) => { impl $crate::LintPass for $ty { fn name(&self) -> &'static str { stringify!($ty) } } impl $ty { pub fn get_lints() -> $crate::LintArray { $crate::lint_array!($($lint),*) } } }; } /// Declares a type named `$name` which implements `LintPass`. /// To the right of `=>` a comma separated list of `Lint` statics is given. #[macro_export] macro_rules! declare_lint_pass { ($(#[$m:meta])* $name:ident => [$($lint:expr),* $(,)?]) => { $(#[$m])* #[derive(Copy, Clone)] pub struct $name; $crate::impl_lint_pass!($name => [$($lint),*]); }; }