use crate::errors::{CheckNameUnknownTool, RequestedLevel, UnsupportedGroup}; use crate::lints::{ DeprecatedLintNameFromCommandLine, RemovedLintFromCommandLine, RenamedLintFromCommandLine, UnknownLintFromCommandLine, }; use crate::{ builtin::MISSING_DOCS, context::{CheckLintNameResult, LintStore}, fluent_generated as fluent, late::unerased_lint_store, lints::{ DeprecatedLintName, IgnoredUnlessCrateSpecified, OverruledAttributeLint, RemovedLint, RenamedLint, RenamedLintSuggestion, UnknownLint, UnknownLintSuggestion, }, }; use rustc_ast as ast; use rustc_ast_pretty::pprust; use rustc_data_structures::fx::FxHashMap; use rustc_errors::{DecorateLint, DiagnosticBuilder, DiagnosticMessage, MultiSpan}; use rustc_feature::{Features, GateIssue}; use rustc_hir as hir; use rustc_hir::intravisit::{self, Visitor}; use rustc_hir::HirId; use rustc_index::IndexVec; use rustc_middle::hir::nested_filter; use rustc_middle::lint::{ reveal_actual_level, struct_lint_level, LevelAndSource, LintExpectation, LintLevelSource, ShallowLintLevelMap, }; use rustc_middle::query::Providers; use rustc_middle::ty::{RegisteredTools, TyCtxt}; use rustc_session::lint::{ builtin::{ self, FORBIDDEN_LINT_GROUPS, RENAMED_AND_REMOVED_LINTS, SINGLE_USE_LIFETIMES, UNFULFILLED_LINT_EXPECTATIONS, UNKNOWN_LINTS, UNUSED_ATTRIBUTES, }, Level, Lint, LintExpectationId, LintId, }; use rustc_session::parse::feature_err; use rustc_session::Session; use rustc_span::symbol::{sym, Symbol}; use rustc_span::{Span, DUMMY_SP}; use crate::errors::{ MalformedAttribute, MalformedAttributeSub, OverruledAttribute, OverruledAttributeSub, UnknownToolInScopedLint, }; /// Collection of lint levels for the whole crate. /// This is used by AST-based lints, which do not /// wait until we have built HIR to be emitted. #[derive(Debug)] struct LintLevelSets { /// Linked list of specifications. list: IndexVec, } rustc_index::newtype_index! { #[custom_encodable] // we don't need encoding struct LintStackIndex { const COMMAND_LINE = 0; } } /// Specifications found at this position in the stack. This map only represents the lints /// found for one set of attributes (like `shallow_lint_levels_on` does). /// /// We store the level specifications as a linked list. /// Each `LintSet` represents a set of attributes on the same AST node. /// The `parent` forms a linked list that matches the AST tree. /// This way, walking the linked list is equivalent to walking the AST bottom-up /// to find the specifications for a given lint. #[derive(Debug)] struct LintSet { // -A,-W,-D flags, a `Symbol` for the flag itself and `Level` for which // flag. specs: FxHashMap, parent: LintStackIndex, } impl LintLevelSets { fn new() -> Self { LintLevelSets { list: IndexVec::new() } } fn get_lint_level( &self, lint: &'static Lint, idx: LintStackIndex, aux: Option<&FxHashMap>, sess: &Session, ) -> LevelAndSource { let lint = LintId::of(lint); let (level, mut src) = self.raw_lint_id_level(lint, idx, aux); let level = reveal_actual_level(level, &mut src, sess, lint, |id| { self.raw_lint_id_level(id, idx, aux) }); (level, src) } fn raw_lint_id_level( &self, id: LintId, mut idx: LintStackIndex, aux: Option<&FxHashMap>, ) -> (Option, LintLevelSource) { if let Some(specs) = aux { if let Some(&(level, src)) = specs.get(&id) { return (Some(level), src); } } loop { let LintSet { ref specs, parent } = self.list[idx]; if let Some(&(level, src)) = specs.get(&id) { return (Some(level), src); } if idx == COMMAND_LINE { return (None, LintLevelSource::Default); } idx = parent; } } } fn lint_expectations(tcx: TyCtxt<'_>, (): ()) -> Vec<(LintExpectationId, LintExpectation)> { let store = unerased_lint_store(tcx); let mut builder = LintLevelsBuilder { sess: tcx.sess, features: tcx.features(), provider: QueryMapExpectationsWrapper { tcx, cur: hir::CRATE_HIR_ID, specs: ShallowLintLevelMap::default(), expectations: Vec::new(), unstable_to_stable_ids: FxHashMap::default(), empty: FxHashMap::default(), }, warn_about_weird_lints: false, store, registered_tools: &tcx.registered_tools(()), }; builder.add_command_line(); builder.add_id(hir::CRATE_HIR_ID); tcx.hir().walk_toplevel_module(&mut builder); tcx.sess.diagnostic().update_unstable_expectation_id(&builder.provider.unstable_to_stable_ids); builder.provider.expectations } #[instrument(level = "trace", skip(tcx), ret)] fn shallow_lint_levels_on(tcx: TyCtxt<'_>, owner: hir::OwnerId) -> ShallowLintLevelMap { let store = unerased_lint_store(tcx); let attrs = tcx.hir_attrs(owner); let mut levels = LintLevelsBuilder { sess: tcx.sess, features: tcx.features(), provider: LintLevelQueryMap { tcx, cur: owner.into(), specs: ShallowLintLevelMap::default(), empty: FxHashMap::default(), attrs, }, warn_about_weird_lints: false, store, registered_tools: &tcx.registered_tools(()), }; if owner == hir::CRATE_OWNER_ID { levels.add_command_line(); } match attrs.map.range(..) { // There is only something to do if there are attributes at all. [] => {} // Most of the time, there is only one attribute. Avoid fetching HIR in that case. [(local_id, _)] => levels.add_id(HirId { owner, local_id: *local_id }), // Otherwise, we need to visit the attributes in source code order, so we fetch HIR and do // a standard visit. // FIXME(#102522) Just iterate on attrs once that iteration order matches HIR's. _ => match tcx.hir().owner(owner) { hir::OwnerNode::Item(item) => levels.visit_item(item), hir::OwnerNode::ForeignItem(item) => levels.visit_foreign_item(item), hir::OwnerNode::TraitItem(item) => levels.visit_trait_item(item), hir::OwnerNode::ImplItem(item) => levels.visit_impl_item(item), hir::OwnerNode::Crate(mod_) => { levels.add_id(hir::CRATE_HIR_ID); levels.visit_mod(mod_, mod_.spans.inner_span, hir::CRATE_HIR_ID) } }, } let specs = levels.provider.specs; #[cfg(debug_assertions)] for (_, v) in specs.specs.iter() { debug_assert!(!v.is_empty()); } specs } pub struct TopDown { sets: LintLevelSets, cur: LintStackIndex, } pub trait LintLevelsProvider { fn current_specs(&self) -> &FxHashMap; fn insert(&mut self, id: LintId, lvl: LevelAndSource); fn get_lint_level(&self, lint: &'static Lint, sess: &Session) -> LevelAndSource; fn push_expectation(&mut self, _id: LintExpectationId, _expectation: LintExpectation) {} } impl LintLevelsProvider for TopDown { fn current_specs(&self) -> &FxHashMap { &self.sets.list[self.cur].specs } fn insert(&mut self, id: LintId, lvl: LevelAndSource) { self.sets.list[self.cur].specs.insert(id, lvl); } fn get_lint_level(&self, lint: &'static Lint, sess: &Session) -> LevelAndSource { self.sets.get_lint_level(lint, self.cur, Some(self.current_specs()), sess) } } struct LintLevelQueryMap<'tcx> { tcx: TyCtxt<'tcx>, cur: HirId, specs: ShallowLintLevelMap, /// Empty hash map to simplify code. empty: FxHashMap, attrs: &'tcx hir::AttributeMap<'tcx>, } impl LintLevelsProvider for LintLevelQueryMap<'_> { fn current_specs(&self) -> &FxHashMap { self.specs.specs.get(&self.cur.local_id).unwrap_or(&self.empty) } fn insert(&mut self, id: LintId, lvl: LevelAndSource) { self.specs.specs.get_mut_or_insert_default(self.cur.local_id).insert(id, lvl); } fn get_lint_level(&self, lint: &'static Lint, _: &Session) -> LevelAndSource { self.specs.lint_level_id_at_node(self.tcx, LintId::of(lint), self.cur) } } struct QueryMapExpectationsWrapper<'tcx> { tcx: TyCtxt<'tcx>, /// HirId of the currently investigated element. cur: HirId, /// Level map for `cur`. specs: ShallowLintLevelMap, expectations: Vec<(LintExpectationId, LintExpectation)>, unstable_to_stable_ids: FxHashMap, /// Empty hash map to simplify code. empty: FxHashMap, } impl LintLevelsProvider for QueryMapExpectationsWrapper<'_> { fn current_specs(&self) -> &FxHashMap { self.specs.specs.get(&self.cur.local_id).unwrap_or(&self.empty) } fn insert(&mut self, id: LintId, lvl: LevelAndSource) { self.specs.specs.get_mut_or_insert_default(self.cur.local_id).insert(id, lvl); } fn get_lint_level(&self, lint: &'static Lint, _: &Session) -> LevelAndSource { // We cannot use `tcx.lint_level_at_node` because we want to know in which order the // attributes have been inserted, in particular whether an `expect` follows a `forbid`. self.specs.lint_level_id_at_node(self.tcx, LintId::of(lint), self.cur) } fn push_expectation(&mut self, id: LintExpectationId, expectation: LintExpectation) { let LintExpectationId::Stable { attr_id: Some(attr_id), hir_id, attr_index, .. } = id else { bug!("unstable expectation id should already be mapped") }; let key = LintExpectationId::Unstable { attr_id, lint_index: None }; self.unstable_to_stable_ids.entry(key).or_insert(LintExpectationId::Stable { hir_id, attr_index, lint_index: None, attr_id: None, }); self.expectations.push((id.normalize(), expectation)); } } impl<'tcx> LintLevelsBuilder<'_, LintLevelQueryMap<'tcx>> { fn add_id(&mut self, hir_id: HirId) { self.provider.cur = hir_id; self.add( self.provider.attrs.get(hir_id.local_id), hir_id == hir::CRATE_HIR_ID, Some(hir_id), ); } } impl<'tcx> Visitor<'tcx> for LintLevelsBuilder<'_, LintLevelQueryMap<'tcx>> { type NestedFilter = nested_filter::OnlyBodies; fn nested_visit_map(&mut self) -> Self::Map { self.provider.tcx.hir() } fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) { self.add_id(param.hir_id); intravisit::walk_param(self, param); } fn visit_item(&mut self, it: &'tcx hir::Item<'tcx>) { self.add_id(it.hir_id()); intravisit::walk_item(self, it); } fn visit_foreign_item(&mut self, it: &'tcx hir::ForeignItem<'tcx>) { self.add_id(it.hir_id()); intravisit::walk_foreign_item(self, it); } fn visit_stmt(&mut self, e: &'tcx hir::Stmt<'tcx>) { // We will call `add_id` when we walk // the `StmtKind`. The outer statement itself doesn't // define the lint levels. intravisit::walk_stmt(self, e); } fn visit_expr(&mut self, e: &'tcx hir::Expr<'tcx>) { self.add_id(e.hir_id); intravisit::walk_expr(self, e); } fn visit_expr_field(&mut self, f: &'tcx hir::ExprField<'tcx>) { self.add_id(f.hir_id); intravisit::walk_expr_field(self, f); } fn visit_field_def(&mut self, s: &'tcx hir::FieldDef<'tcx>) { self.add_id(s.hir_id); intravisit::walk_field_def(self, s); } fn visit_variant(&mut self, v: &'tcx hir::Variant<'tcx>) { self.add_id(v.hir_id); intravisit::walk_variant(self, v); } fn visit_local(&mut self, l: &'tcx hir::Local<'tcx>) { self.add_id(l.hir_id); intravisit::walk_local(self, l); } fn visit_arm(&mut self, a: &'tcx hir::Arm<'tcx>) { self.add_id(a.hir_id); intravisit::walk_arm(self, a); } fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) { self.add_id(trait_item.hir_id()); intravisit::walk_trait_item(self, trait_item); } fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) { self.add_id(impl_item.hir_id()); intravisit::walk_impl_item(self, impl_item); } } impl<'tcx> LintLevelsBuilder<'_, QueryMapExpectationsWrapper<'tcx>> { fn add_id(&mut self, hir_id: HirId) { // Change both the `HirId` and the associated specs. self.provider.cur = hir_id; self.provider.specs.specs.clear(); self.add(self.provider.tcx.hir().attrs(hir_id), hir_id == hir::CRATE_HIR_ID, Some(hir_id)); } } impl<'tcx> Visitor<'tcx> for LintLevelsBuilder<'_, QueryMapExpectationsWrapper<'tcx>> { type NestedFilter = nested_filter::All; fn nested_visit_map(&mut self) -> Self::Map { self.provider.tcx.hir() } fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) { self.add_id(param.hir_id); intravisit::walk_param(self, param); } fn visit_item(&mut self, it: &'tcx hir::Item<'tcx>) { self.add_id(it.hir_id()); intravisit::walk_item(self, it); } fn visit_foreign_item(&mut self, it: &'tcx hir::ForeignItem<'tcx>) { self.add_id(it.hir_id()); intravisit::walk_foreign_item(self, it); } fn visit_stmt(&mut self, e: &'tcx hir::Stmt<'tcx>) { // We will call `add_id` when we walk // the `StmtKind`. The outer statement itself doesn't // define the lint levels. intravisit::walk_stmt(self, e); } fn visit_expr(&mut self, e: &'tcx hir::Expr<'tcx>) { self.add_id(e.hir_id); intravisit::walk_expr(self, e); } fn visit_field_def(&mut self, s: &'tcx hir::FieldDef<'tcx>) { self.add_id(s.hir_id); intravisit::walk_field_def(self, s); } fn visit_variant(&mut self, v: &'tcx hir::Variant<'tcx>) { self.add_id(v.hir_id); intravisit::walk_variant(self, v); } fn visit_local(&mut self, l: &'tcx hir::Local<'tcx>) { self.add_id(l.hir_id); intravisit::walk_local(self, l); } fn visit_arm(&mut self, a: &'tcx hir::Arm<'tcx>) { self.add_id(a.hir_id); intravisit::walk_arm(self, a); } fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) { self.add_id(trait_item.hir_id()); intravisit::walk_trait_item(self, trait_item); } fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) { self.add_id(impl_item.hir_id()); intravisit::walk_impl_item(self, impl_item); } } pub struct LintLevelsBuilder<'s, P> { sess: &'s Session, features: &'s Features, provider: P, warn_about_weird_lints: bool, store: &'s LintStore, registered_tools: &'s RegisteredTools, } pub(crate) struct BuilderPush { prev: LintStackIndex, } impl<'s> LintLevelsBuilder<'s, TopDown> { pub(crate) fn new( sess: &'s Session, features: &'s Features, warn_about_weird_lints: bool, store: &'s LintStore, registered_tools: &'s RegisteredTools, ) -> Self { let mut builder = LintLevelsBuilder { sess, features, provider: TopDown { sets: LintLevelSets::new(), cur: COMMAND_LINE }, warn_about_weird_lints, store, registered_tools, }; builder.process_command_line(); assert_eq!(builder.provider.sets.list.len(), 1); builder } fn process_command_line(&mut self) { self.provider.cur = self .provider .sets .list .push(LintSet { specs: FxHashMap::default(), parent: COMMAND_LINE }); self.add_command_line(); } /// Pushes a list of AST lint attributes onto this context. /// /// This function will return a `BuilderPush` object which should be passed /// to `pop` when this scope for the attributes provided is exited. /// /// This function will perform a number of tasks: /// /// * It'll validate all lint-related attributes in `attrs` /// * It'll mark all lint-related attributes as used /// * Lint levels will be updated based on the attributes provided /// * Lint attributes are validated, e.g., a `#[forbid]` can't be switched to /// `#[allow]` /// /// Don't forget to call `pop`! pub(crate) fn push( &mut self, attrs: &[ast::Attribute], is_crate_node: bool, source_hir_id: Option, ) -> BuilderPush { let prev = self.provider.cur; self.provider.cur = self.provider.sets.list.push(LintSet { specs: FxHashMap::default(), parent: prev }); self.add(attrs, is_crate_node, source_hir_id); if self.provider.current_specs().is_empty() { self.provider.sets.list.pop(); self.provider.cur = prev; } BuilderPush { prev } } /// Called after `push` when the scope of a set of attributes are exited. pub(crate) fn pop(&mut self, push: BuilderPush) { self.provider.cur = push.prev; std::mem::forget(push); } } #[cfg(debug_assertions)] impl Drop for BuilderPush { fn drop(&mut self) { panic!("Found a `push` without a `pop`."); } } impl<'s, P: LintLevelsProvider> LintLevelsBuilder<'s, P> { pub(crate) fn sess(&self) -> &Session { self.sess } pub(crate) fn features(&self) -> &Features { self.features } pub(crate) fn lint_store(&self) -> &LintStore { self.store } fn current_specs(&self) -> &FxHashMap { self.provider.current_specs() } fn insert(&mut self, id: LintId, lvl: LevelAndSource) { self.provider.insert(id, lvl) } fn add_command_line(&mut self) { for &(ref lint_name, level) in &self.sess.opts.lint_opts { // Checks the validity of lint names derived from the command line. let (tool_name, lint_name_only) = parse_lint_and_tool_name(lint_name); if lint_name_only == crate::WARNINGS.name_lower() && matches!(level, Level::ForceWarn(_)) { self.sess.emit_err(UnsupportedGroup { lint_group: crate::WARNINGS.name_lower() }); } match self.store.check_lint_name(lint_name_only, tool_name, self.registered_tools) { CheckLintNameResult::Renamed(ref replace) => { let name = lint_name.as_str(); let suggestion = RenamedLintSuggestion::WithoutSpan { replace }; let requested_level = RequestedLevel { level, lint_name }; let lint = RenamedLintFromCommandLine { name, suggestion, requested_level }; self.emit_lint(RENAMED_AND_REMOVED_LINTS, lint); } CheckLintNameResult::Removed(ref reason) => { let name = lint_name.as_str(); let requested_level = RequestedLevel { level, lint_name }; let lint = RemovedLintFromCommandLine { name, reason, requested_level }; self.emit_lint(RENAMED_AND_REMOVED_LINTS, lint); } CheckLintNameResult::NoLint(suggestion) => { let name = lint_name.clone(); let suggestion = suggestion.map(|replace| UnknownLintSuggestion::WithoutSpan { replace }); let requested_level = RequestedLevel { level, lint_name }; let lint = UnknownLintFromCommandLine { name, suggestion, requested_level }; self.emit_lint(UNKNOWN_LINTS, lint); } CheckLintNameResult::Tool(Err((Some(_), ref replace))) => { let name = lint_name.clone(); let requested_level = RequestedLevel { level, lint_name }; let lint = DeprecatedLintNameFromCommandLine { name, replace, requested_level }; self.emit_lint(RENAMED_AND_REMOVED_LINTS, lint); } CheckLintNameResult::NoTool => { self.sess.emit_err(CheckNameUnknownTool { tool_name: tool_name.unwrap(), sub: RequestedLevel { level, lint_name }, }); } _ => {} }; let orig_level = level; let lint_flag_val = Symbol::intern(lint_name); let Ok(ids) = self.store.find_lints(&lint_name) else { // errors already handled above continue; }; for id in ids { // ForceWarn and Forbid cannot be overridden if let Some((Level::ForceWarn(_) | Level::Forbid, _)) = self.current_specs().get(&id) { continue; } if self.check_gated_lint(id, DUMMY_SP, true) { let src = LintLevelSource::CommandLine(lint_flag_val, orig_level); self.insert(id, (level, src)); } } } } /// Attempts to insert the `id` to `level_src` map entry. If unsuccessful /// (e.g. if a forbid was already inserted on the same scope), then emits a /// diagnostic with no change to `specs`. fn insert_spec(&mut self, id: LintId, (mut level, src): LevelAndSource) { let (old_level, old_src) = self.provider.get_lint_level(id.lint, &self.sess); if let Level::Expect(id) = &mut level && let LintExpectationId::Stable { .. } = id { *id = id.normalize(); } // Setting to a non-forbid level is an error if the lint previously had // a forbid level. Note that this is not necessarily true even with a // `#[forbid(..)]` attribute present, as that is overridden by `--cap-lints`. // // This means that this only errors if we're truly lowering the lint // level from forbid. if level != Level::Forbid { if let Level::Forbid = old_level { // Backwards compatibility check: // // We used to not consider `forbid(lint_group)` // as preventing `allow(lint)` for some lint `lint` in // `lint_group`. For now, issue a future-compatibility // warning for this case. let id_name = id.lint.name_lower(); let fcw_warning = match old_src { LintLevelSource::Default => false, LintLevelSource::Node { name, .. } => self.store.is_lint_group(name), LintLevelSource::CommandLine(symbol, _) => self.store.is_lint_group(symbol), }; debug!( "fcw_warning={:?}, specs.get(&id) = {:?}, old_src={:?}, id_name={:?}", fcw_warning, self.current_specs(), old_src, id_name ); let sub = match old_src { LintLevelSource::Default => { OverruledAttributeSub::DefaultSource { id: id.to_string() } } LintLevelSource::Node { span, reason, .. } => { OverruledAttributeSub::NodeSource { span, reason } } LintLevelSource::CommandLine(_, _) => OverruledAttributeSub::CommandLineSource, }; if !fcw_warning { self.sess.emit_err(OverruledAttribute { span: src.span(), overruled: src.span(), lint_level: level.as_str(), lint_source: src.name(), sub, }); } else { self.emit_spanned_lint( FORBIDDEN_LINT_GROUPS, src.span().into(), OverruledAttributeLint { overruled: src.span(), lint_level: level.as_str(), lint_source: src.name(), sub, }, ); } // Retain the forbid lint level, unless we are // issuing a FCW. In the FCW case, we want to // respect the new setting. if !fcw_warning { return; } } } // The lint `unfulfilled_lint_expectations` can't be expected, as it would suppress itself. // Handling expectations of this lint would add additional complexity with little to no // benefit. The expect level for this lint will therefore be ignored. if let Level::Expect(_) = level && id == LintId::of(UNFULFILLED_LINT_EXPECTATIONS) { return; } match (old_level, level) { // If the new level is an expectation store it in `ForceWarn` (Level::ForceWarn(_), Level::Expect(expectation_id)) => { self.insert(id, (Level::ForceWarn(Some(expectation_id)), old_src)) } // Keep `ForceWarn` level but drop the expectation (Level::ForceWarn(_), _) => self.insert(id, (Level::ForceWarn(None), old_src)), // Set the lint level as normal _ => self.insert(id, (level, src)), }; } fn add(&mut self, attrs: &[ast::Attribute], is_crate_node: bool, source_hir_id: Option) { let sess = self.sess; for (attr_index, attr) in attrs.iter().enumerate() { if attr.has_name(sym::automatically_derived) { self.insert( LintId::of(SINGLE_USE_LIFETIMES), (Level::Allow, LintLevelSource::Default), ); continue; } // `#[doc(hidden)]` disables missing_docs check. if attr.has_name(sym::doc) && attr .meta_item_list() .map_or(false, |l| ast::attr::list_contains_name(&l, sym::hidden)) { self.insert(LintId::of(MISSING_DOCS), (Level::Allow, LintLevelSource::Default)); continue; } let level = match Level::from_attr(attr) { None => continue, // This is the only lint level with a `LintExpectationId` that can be created from an attribute Some(Level::Expect(unstable_id)) if let Some(hir_id) = source_hir_id => { let LintExpectationId::Unstable { attr_id, lint_index } = unstable_id else { bug!("stable id Level::from_attr") }; let stable_id = LintExpectationId::Stable { hir_id, attr_index: attr_index.try_into().unwrap(), lint_index, // we pass the previous unstable attr_id such that we can trace the ast id when building a map // to go from unstable to stable id. attr_id: Some(attr_id), }; Level::Expect(stable_id) } Some(lvl) => lvl, }; let Some(mut metas) = attr.meta_item_list() else { continue }; if metas.is_empty() { // This emits the unused_attributes lint for `#[level()]` continue; } // Before processing the lint names, look for a reason (RFC 2383) // at the end. let mut reason = None; let tail_li = &metas[metas.len() - 1]; if let Some(item) = tail_li.meta_item() { match item.kind { ast::MetaItemKind::Word => {} // actual lint names handled later ast::MetaItemKind::NameValue(ref name_value) => { if item.path == sym::reason { if let ast::LitKind::Str(rationale, _) = name_value.kind { if !self.features.lint_reasons { feature_err( &self.sess.parse_sess, sym::lint_reasons, item.span, "lint reasons are experimental", ) .emit(); } reason = Some(rationale); } else { sess.emit_err(MalformedAttribute { span: name_value.span, sub: MalformedAttributeSub::ReasonMustBeStringLiteral( name_value.span, ), }); } // found reason, reslice meta list to exclude it metas.pop().unwrap(); } else { sess.emit_err(MalformedAttribute { span: item.span, sub: MalformedAttributeSub::BadAttributeArgument(item.span), }); } } ast::MetaItemKind::List(_) => { sess.emit_err(MalformedAttribute { span: item.span, sub: MalformedAttributeSub::BadAttributeArgument(item.span), }); } } } for (lint_index, li) in metas.iter_mut().enumerate() { let level = match level { Level::Expect(mut id) => { id.set_lint_index(Some(lint_index as u16)); Level::Expect(id) } level => level, }; let sp = li.span(); let meta_item = match li { ast::NestedMetaItem::MetaItem(meta_item) if meta_item.is_word() => meta_item, _ => { if let Some(item) = li.meta_item() { if let ast::MetaItemKind::NameValue(_) = item.kind { if item.path == sym::reason { sess.emit_err(MalformedAttribute { span: sp, sub: MalformedAttributeSub::ReasonMustComeLast(sp), }); continue; } } } sess.emit_err(MalformedAttribute { span: sp, sub: MalformedAttributeSub::BadAttributeArgument(sp), }); continue; } }; let tool_ident = if meta_item.path.segments.len() > 1 { Some(meta_item.path.segments.remove(0).ident) } else { None }; let tool_name = tool_ident.map(|ident| ident.name); let name = pprust::path_to_string(&meta_item.path); let lint_result = self.store.check_lint_name(&name, tool_name, self.registered_tools); match &lint_result { CheckLintNameResult::Ok(ids) => { // This checks for instances where the user writes `#[expect(unfulfilled_lint_expectations)]` // in that case we want to avoid overriding the lint level but instead add an expectation that // can't be fulfilled. The lint message will include an explanation, that the // `unfulfilled_lint_expectations` lint can't be expected. if let Level::Expect(expect_id) = level { // The `unfulfilled_lint_expectations` lint is not part of any lint groups. Therefore. we // only need to check the slice if it contains a single lint. let is_unfulfilled_lint_expectations = match ids { [lint] => *lint == LintId::of(UNFULFILLED_LINT_EXPECTATIONS), _ => false, }; self.provider.push_expectation( expect_id, LintExpectation::new( reason, sp, is_unfulfilled_lint_expectations, tool_name, ), ); } let src = LintLevelSource::Node { name: meta_item .path .segments .last() .expect("empty lint name") .ident .name, span: sp, reason, }; for &id in *ids { if self.check_gated_lint(id, attr.span, false) { self.insert_spec(id, (level, src)); } } } CheckLintNameResult::Tool(result) => { match *result { Ok(ids) => { let complete_name = &format!("{}::{}", tool_ident.unwrap().name, name); let src = LintLevelSource::Node { name: Symbol::intern(complete_name), span: sp, reason, }; for &id in ids { if self.check_gated_lint(id, attr.span, false) { self.insert_spec(id, (level, src)); } } if let Level::Expect(expect_id) = level { self.provider.push_expectation( expect_id, LintExpectation::new(reason, sp, false, tool_name), ); } } Err((Some(ids), ref new_lint_name)) => { let lint = builtin::RENAMED_AND_REMOVED_LINTS; self.emit_spanned_lint( lint, sp.into(), DeprecatedLintName { name, suggestion: sp, replace: &new_lint_name, }, ); let src = LintLevelSource::Node { name: Symbol::intern(&new_lint_name), span: sp, reason, }; for id in ids { self.insert_spec(*id, (level, src)); } if let Level::Expect(expect_id) = level { self.provider.push_expectation( expect_id, LintExpectation::new(reason, sp, false, tool_name), ); } } Err((None, _)) => { // If Tool(Err(None, _)) is returned, then either the lint does not // exist in the tool or the code was not compiled with the tool and // therefore the lint was never added to the `LintStore`. To detect // this is the responsibility of the lint tool. } } } &CheckLintNameResult::NoTool => { sess.emit_err(UnknownToolInScopedLint { span: tool_ident.map(|ident| ident.span), tool_name: tool_name.unwrap(), lint_name: pprust::path_to_string(&meta_item.path), is_nightly_build: sess.is_nightly_build().then_some(()), }); continue; } _ if !self.warn_about_weird_lints => {} CheckLintNameResult::Renamed(ref replace) => { let suggestion = RenamedLintSuggestion::WithSpan { suggestion: sp, replace }; let name = tool_ident.map(|tool| format!("{tool}::{name}")).unwrap_or(name); let lint = RenamedLint { name: name.as_str(), suggestion }; self.emit_spanned_lint(RENAMED_AND_REMOVED_LINTS, sp.into(), lint); } CheckLintNameResult::Removed(ref reason) => { let name = tool_ident.map(|tool| format!("{tool}::{name}")).unwrap_or(name); let lint = RemovedLint { name: name.as_str(), reason }; self.emit_spanned_lint(RENAMED_AND_REMOVED_LINTS, sp.into(), lint); } CheckLintNameResult::NoLint(suggestion) => { let name = if let Some(tool_ident) = tool_ident { format!("{}::{}", tool_ident.name, name) } else { name.to_string() }; let suggestion = suggestion.map(|replace| { UnknownLintSuggestion::WithSpan { suggestion: sp, replace } }); let lint = UnknownLint { name, suggestion }; self.emit_spanned_lint(UNKNOWN_LINTS, sp.into(), lint); } } // If this lint was renamed, apply the new lint instead of ignoring the attribute. // This happens outside of the match because the new lint should be applied even if // we don't warn about the name change. if let CheckLintNameResult::Renamed(new_name) = lint_result { // Ignore any errors or warnings that happen because the new name is inaccurate // NOTE: `new_name` already includes the tool name, so we don't have to add it again. if let CheckLintNameResult::Ok(ids) = self.store.check_lint_name(&new_name, None, self.registered_tools) { let src = LintLevelSource::Node { name: Symbol::intern(&new_name), span: sp, reason, }; for &id in ids { if self.check_gated_lint(id, attr.span, false) { self.insert_spec(id, (level, src)); } } if let Level::Expect(expect_id) = level { self.provider.push_expectation( expect_id, LintExpectation::new(reason, sp, false, tool_name), ); } } else { panic!("renamed lint does not exist: {new_name}"); } } } } if !is_crate_node { for (id, &(level, ref src)) in self.current_specs().iter() { if !id.lint.crate_level_only { continue; } let LintLevelSource::Node { name: lint_attr_name, span: lint_attr_span, .. } = *src else { continue; }; self.emit_spanned_lint( UNUSED_ATTRIBUTES, lint_attr_span.into(), IgnoredUnlessCrateSpecified { level: level.as_str(), name: lint_attr_name }, ); // don't set a separate error for every lint in the group break; } } } /// Checks if the lint is gated on a feature that is not enabled. /// /// Returns `true` if the lint's feature is enabled. // FIXME only emit this once for each attribute, instead of repeating it 4 times for // pre-expansion lints, post-expansion lints, `shallow_lint_levels_on` and `lint_expectations`. #[track_caller] fn check_gated_lint(&self, lint_id: LintId, span: Span, lint_from_cli: bool) -> bool { if let Some(feature) = lint_id.lint.feature_gate { if !self.features.active(feature) { let lint = builtin::UNKNOWN_LINTS; let (level, src) = self.lint_level(builtin::UNKNOWN_LINTS); struct_lint_level( self.sess, lint, level, src, Some(span.into()), fluent::lint_unknown_gated_lint, |lint| { lint.set_arg("name", lint_id.lint.name_lower()); lint.note(fluent::lint_note); rustc_session::parse::add_feature_diagnostics_for_issue( lint, &self.sess.parse_sess, feature, GateIssue::Language, lint_from_cli, ); lint }, ); return false; } } true } /// Find the lint level for a lint. pub fn lint_level(&self, lint: &'static Lint) -> LevelAndSource { self.provider.get_lint_level(lint, self.sess) } /// Used to emit a lint-related diagnostic based on the current state of /// this lint context. /// /// Return value of the `decorate` closure is ignored, see [`struct_lint_level`] for a detailed explanation. /// /// [`struct_lint_level`]: rustc_middle::lint::struct_lint_level#decorate-signature #[rustc_lint_diagnostics] #[track_caller] pub(crate) fn struct_lint( &self, lint: &'static Lint, span: Option, msg: impl Into, decorate: impl for<'a, 'b> FnOnce( &'b mut DiagnosticBuilder<'a, ()>, ) -> &'b mut DiagnosticBuilder<'a, ()>, ) { let (level, src) = self.lint_level(lint); struct_lint_level(self.sess, lint, level, src, span, msg, decorate) } #[track_caller] pub fn emit_spanned_lint( &self, lint: &'static Lint, span: MultiSpan, decorate: impl for<'a> DecorateLint<'a, ()>, ) { let (level, src) = self.lint_level(lint); struct_lint_level(self.sess, lint, level, src, Some(span), decorate.msg(), |lint| { decorate.decorate_lint(lint) }); } #[track_caller] pub fn emit_lint(&self, lint: &'static Lint, decorate: impl for<'a> DecorateLint<'a, ()>) { let (level, src) = self.lint_level(lint); struct_lint_level(self.sess, lint, level, src, None, decorate.msg(), |lint| { decorate.decorate_lint(lint) }); } } pub(crate) fn provide(providers: &mut Providers) { *providers = Providers { shallow_lint_levels_on, lint_expectations, ..*providers }; } pub fn parse_lint_and_tool_name(lint_name: &str) -> (Option, &str) { match lint_name.split_once("::") { Some((tool_name, lint_name)) => { let tool_name = Symbol::intern(tool_name); (Some(tool_name), lint_name) } None => (None, lint_name), } }