1 //! This module implements some validity checks for attributes.
2 //! In particular it verifies that `#[inline]` and `#[repr]` attributes are
3 //! attached to items that actually support them and if there are
4 //! conflicts between multiple such attributes attached to the same
8 self, AttrApplication, DebugVisualizerUnreadable, InvalidAttrAtCrateLevel, ObjectLifetimeErr,
9 OnlyHasEffectOn, TransparentIncompatible, UnrecognizedReprHint,
11 use rustc_ast::{ast, AttrStyle, Attribute, LitKind, MetaItemKind, MetaItemLit, NestedMetaItem};
12 use rustc_data_structures::fx::FxHashMap;
13 use rustc_errors::{fluent, Applicability, MultiSpan};
14 use rustc_expand::base::resolve_path;
15 use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
17 use rustc_hir::def_id::LocalDefId;
18 use rustc_hir::intravisit::{self, Visitor};
20 self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID, CRATE_OWNER_ID,
22 use rustc_hir::{MethodKind, Target};
23 use rustc_middle::hir::nested_filter;
24 use rustc_middle::middle::resolve_lifetime::ObjectLifetimeDefault;
25 use rustc_middle::ty::query::Providers;
26 use rustc_middle::ty::TyCtxt;
27 use rustc_session::lint::builtin::{
28 CONFLICTING_REPR_HINTS, INVALID_DOC_ATTRIBUTES, UNUSED_ATTRIBUTES,
30 use rustc_session::parse::feature_err;
31 use rustc_span::symbol::{kw, sym, Symbol};
32 use rustc_span::{Span, DUMMY_SP};
33 use rustc_target::spec::abi::Abi;
34 use std::collections::hash_map::Entry;
36 pub(crate) fn target_from_impl_item<'tcx>(
38 impl_item: &hir::ImplItem<'_>,
40 match impl_item.kind {
41 hir::ImplItemKind::Const(..) => Target::AssocConst,
42 hir::ImplItemKind::Fn(..) => {
43 let parent_def_id = tcx.hir().get_parent_item(impl_item.hir_id()).def_id;
44 let containing_item = tcx.hir().expect_item(parent_def_id);
45 let containing_impl_is_for_trait = match &containing_item.kind {
46 hir::ItemKind::Impl(impl_) => impl_.of_trait.is_some(),
47 _ => bug!("parent of an ImplItem must be an Impl"),
49 if containing_impl_is_for_trait {
50 Target::Method(MethodKind::Trait { body: true })
52 Target::Method(MethodKind::Inherent)
55 hir::ImplItemKind::Type(..) => Target::AssocTy,
59 #[derive(Clone, Copy)]
61 Item(&'tcx Item<'tcx>),
65 struct CheckAttrVisitor<'tcx> {
69 impl CheckAttrVisitor<'_> {
70 /// Checks any attribute.
76 item: Option<ItemLike<'_>>,
78 let mut doc_aliases = FxHashMap::default();
79 let mut is_valid = true;
80 let mut specified_inline = None;
81 let mut seen = FxHashMap::default();
82 let attrs = self.tcx.hir().attrs(hir_id);
84 let attr_is_valid = match attr.name_or_empty() {
85 sym::do_not_recommend => self.check_do_not_recommend(attr.span, target),
86 sym::inline => self.check_inline(hir_id, attr, span, target),
87 sym::no_coverage => self.check_no_coverage(hir_id, attr, span, target),
88 sym::non_exhaustive => self.check_non_exhaustive(hir_id, attr, span, target),
89 sym::marker => self.check_marker(hir_id, attr, span, target),
90 sym::rustc_must_implement_one_of => {
91 self.check_rustc_must_implement_one_of(attr, span, target)
93 sym::target_feature => self.check_target_feature(hir_id, attr, span, target),
94 sym::thread_local => self.check_thread_local(attr, span, target),
95 sym::track_caller => {
96 self.check_track_caller(hir_id, attr.span, attrs, span, target)
98 sym::doc => self.check_doc_attrs(
102 &mut specified_inline,
105 sym::no_link => self.check_no_link(hir_id, &attr, span, target),
106 sym::export_name => self.check_export_name(hir_id, &attr, span, target),
107 sym::rustc_layout_scalar_valid_range_start
108 | sym::rustc_layout_scalar_valid_range_end => {
109 self.check_rustc_layout_scalar_valid_range(&attr, span, target)
111 sym::allow_internal_unstable => {
112 self.check_allow_internal_unstable(hir_id, &attr, span, target, &attrs)
114 sym::debugger_visualizer => self.check_debugger_visualizer(&attr, target),
115 sym::rustc_allow_const_fn_unstable => {
116 self.check_rustc_allow_const_fn_unstable(hir_id, &attr, span, target)
118 sym::rustc_std_internal_symbol => {
119 self.check_rustc_std_internal_symbol(&attr, span, target)
121 sym::naked => self.check_naked(hir_id, attr, span, target),
122 sym::rustc_legacy_const_generics => {
123 self.check_rustc_legacy_const_generics(hir_id, &attr, span, target, item)
125 sym::rustc_lint_query_instability => {
126 self.check_rustc_lint_query_instability(hir_id, &attr, span, target)
128 sym::rustc_lint_diagnostics => {
129 self.check_rustc_lint_diagnostics(hir_id, &attr, span, target)
131 sym::rustc_lint_opt_ty => self.check_rustc_lint_opt_ty(&attr, span, target),
132 sym::rustc_lint_opt_deny_field_access => {
133 self.check_rustc_lint_opt_deny_field_access(&attr, span, target)
137 | sym::rustc_if_this_changed
138 | sym::rustc_then_this_would_need => self.check_rustc_dirty_clean(&attr),
139 sym::cmse_nonsecure_entry => {
140 self.check_cmse_nonsecure_entry(hir_id, attr, span, target)
142 sym::collapse_debuginfo => self.check_collapse_debuginfo(attr, span, target),
143 sym::const_trait => self.check_const_trait(attr, span, target),
144 sym::must_not_suspend => self.check_must_not_suspend(&attr, span, target),
145 sym::must_use => self.check_must_use(hir_id, &attr, target),
146 sym::rustc_pass_by_value => self.check_pass_by_value(&attr, span, target),
147 sym::rustc_allow_incoherent_impl => {
148 self.check_allow_incoherent_impl(&attr, span, target)
150 sym::rustc_has_incoherent_inherent_impls => {
151 self.check_has_incoherent_inherent_impls(&attr, span, target)
153 sym::rustc_const_unstable
154 | sym::rustc_const_stable
157 | sym::rustc_allowed_through_unstable_modules
158 | sym::rustc_promotable => self.check_stability_promotable(&attr, span, target),
159 sym::link_ordinal => self.check_link_ordinal(&attr, span, target),
162 is_valid &= attr_is_valid;
165 match attr.name_or_empty() {
166 sym::cold => self.check_cold(hir_id, attr, span, target),
167 sym::link => self.check_link(hir_id, attr, span, target),
168 sym::link_name => self.check_link_name(hir_id, attr, span, target),
169 sym::link_section => self.check_link_section(hir_id, attr, span, target),
170 sym::no_mangle => self.check_no_mangle(hir_id, attr, span, target),
171 sym::deprecated => self.check_deprecated(hir_id, attr, span, target),
172 sym::macro_use | sym::macro_escape => self.check_macro_use(hir_id, attr, target),
173 sym::path => self.check_generic_attr(hir_id, attr, target, Target::Mod),
174 sym::plugin_registrar => self.check_plugin_registrar(hir_id, attr, target),
175 sym::macro_export => self.check_macro_export(hir_id, attr, target),
176 sym::ignore | sym::should_panic | sym::proc_macro_derive => {
177 self.check_generic_attr(hir_id, attr, target, Target::Fn)
179 sym::automatically_derived => {
180 self.check_generic_attr(hir_id, attr, target, Target::Impl)
182 sym::no_implicit_prelude => {
183 self.check_generic_attr(hir_id, attr, target, Target::Mod)
185 sym::rustc_object_lifetime_default => self.check_object_lifetime_default(hir_id),
189 let builtin = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
191 if hir_id != CRATE_HIR_ID {
192 if let Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) =
193 attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name))
196 ast::AttrStyle::Outer => self.tcx.emit_spanned_lint(
200 errors::OuterCrateLevelAttr,
202 ast::AttrStyle::Inner => self.tcx.emit_spanned_lint(
206 errors::InnerCrateLevelAttr,
212 if let Some(BuiltinAttribute { duplicates, .. }) = builtin {
213 check_duplicates(self.tcx, attr, hir_id, *duplicates, &mut seen);
216 self.check_unused_attribute(hir_id, attr)
223 self.check_repr(attrs, span, target, item, hir_id);
224 self.check_used(attrs, target);
227 fn inline_attr_str_error_with_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
228 self.tcx.emit_spanned_lint(
232 errors::IgnoredAttrWithMacro { sym },
236 fn inline_attr_str_error_without_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
237 self.tcx.emit_spanned_lint(
241 errors::IgnoredAttr { sym },
245 /// Checks if `#[do_not_recommend]` is applied on a trait impl.
246 fn check_do_not_recommend(&self, attr_span: Span, target: Target) -> bool {
247 if let Target::Impl = target {
250 self.tcx.sess.emit_err(errors::IncorrectDoNotRecommendLocation { span: attr_span });
255 /// Checks if an `#[inline]` is applied to a function or a closure. Returns `true` if valid.
256 fn check_inline(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
260 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
261 Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
262 self.tcx.emit_spanned_lint(
266 errors::IgnoredInlineAttrFnProto,
270 // FIXME(#65833): We permit associated consts to have an `#[inline]` attribute with
271 // just a lint, because we previously erroneously allowed it and some crates used it
272 // accidentally, to be compatible with crates depending on them, we can't throw an
274 Target::AssocConst => {
275 self.tcx.emit_spanned_lint(
279 errors::IgnoredInlineAttrConstants,
283 // FIXME(#80564): Same for fields, arms, and macro defs
284 Target::Field | Target::Arm | Target::MacroDef => {
285 self.inline_attr_str_error_with_macro_def(hir_id, attr, "inline");
289 self.tcx.sess.emit_err(errors::InlineNotFnOrClosure {
290 attr_span: attr.span,
298 /// Checks if a `#[no_coverage]` is applied directly to a function
299 fn check_no_coverage(
307 // no_coverage on function is fine
310 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
312 // function prototypes can't be covered
313 Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
314 self.tcx.emit_spanned_lint(
318 errors::IgnoredNoCoverageFnProto,
323 Target::Mod | Target::ForeignMod | Target::Impl | Target::Trait => {
324 self.tcx.emit_spanned_lint(
328 errors::IgnoredNoCoveragePropagate,
333 Target::Expression | Target::Statement | Target::Arm => {
334 self.tcx.emit_spanned_lint(
338 errors::IgnoredNoCoverageFnDefn,
344 self.tcx.sess.emit_err(errors::IgnoredNoCoverageNotCoverable {
345 attr_span: attr.span,
353 fn check_generic_attr(
358 allowed_target: Target,
360 if target != allowed_target {
361 self.tcx.emit_spanned_lint(
366 attr_name: attr.name_or_empty(),
367 target_name: allowed_target.name().replace(' ', "_"),
373 /// Checks if `#[naked]` is applied to a function definition.
374 fn check_naked(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
377 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
378 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
379 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
380 // erroneously allowed it and some crates used it accidentally, to be compatible
381 // with crates depending on them, we can't throw an error here.
382 Target::Field | Target::Arm | Target::MacroDef => {
383 self.inline_attr_str_error_with_macro_def(hir_id, attr, "naked");
387 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
388 attr_span: attr.span,
390 on_crate: hir_id == CRATE_HIR_ID,
397 /// Checks if `#[cmse_nonsecure_entry]` is applied to a function definition.
398 fn check_cmse_nonsecure_entry(
407 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
409 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
410 attr_span: attr.span,
412 on_crate: hir_id == CRATE_HIR_ID,
419 /// Debugging aid for `object_lifetime_default` query.
420 fn check_object_lifetime_default(&self, hir_id: HirId) {
422 if let Some(generics) = tcx.hir().get_generics(tcx.hir().local_def_id(hir_id)) {
423 for p in generics.params {
424 let hir::GenericParamKind::Type { .. } = p.kind else { continue };
425 let default = tcx.object_lifetime_default(p.def_id);
426 let repr = match default {
427 ObjectLifetimeDefault::Empty => "BaseDefault".to_owned(),
428 ObjectLifetimeDefault::Static => "'static".to_owned(),
429 ObjectLifetimeDefault::Param(def_id) => tcx.item_name(def_id).to_string(),
430 ObjectLifetimeDefault::Ambiguous => "Ambiguous".to_owned(),
432 tcx.sess.emit_err(ObjectLifetimeErr { span: p.span, repr });
437 /// Checks if `#[collapse_debuginfo]` is applied to a macro.
438 fn check_collapse_debuginfo(&self, attr: &Attribute, span: Span, target: Target) -> bool {
440 Target::MacroDef => true,
444 .emit_err(errors::CollapseDebuginfo { attr_span: attr.span, defn_span: span });
450 /// Checks if a `#[track_caller]` is applied to a non-naked function. Returns `true` if valid.
451 fn check_track_caller(
460 _ if attrs.iter().any(|attr| attr.has_name(sym::naked)) => {
461 self.tcx.sess.emit_err(errors::NakedTrackedCaller { attr_span });
464 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => true,
465 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
466 // `#[track_caller]` attribute with just a lint, because we previously
467 // erroneously allowed it and some crates used it accidentally, to be compatible
468 // with crates depending on them, we can't throw an error here.
469 Target::Field | Target::Arm | Target::MacroDef => {
471 self.inline_attr_str_error_with_macro_def(hir_id, attr, "track_caller");
476 self.tcx.sess.emit_err(errors::TrackedCallerWrongLocation {
479 on_crate: hir_id == CRATE_HIR_ID,
486 /// Checks if the `#[non_exhaustive]` attribute on an `item` is valid. Returns `true` if valid.
487 fn check_non_exhaustive(
495 Target::Struct | Target::Enum | Target::Variant => true,
496 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
497 // `#[non_exhaustive]` attribute with just a lint, because we previously
498 // erroneously allowed it and some crates used it accidentally, to be compatible
499 // with crates depending on them, we can't throw an error here.
500 Target::Field | Target::Arm | Target::MacroDef => {
501 self.inline_attr_str_error_with_macro_def(hir_id, attr, "non_exhaustive");
505 self.tcx.sess.emit_err(errors::NonExhaustiveWrongLocation {
506 attr_span: attr.span,
514 /// Checks if the `#[marker]` attribute on an `item` is valid. Returns `true` if valid.
515 fn check_marker(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
517 Target::Trait => true,
518 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
519 // `#[marker]` attribute with just a lint, because we previously
520 // erroneously allowed it and some crates used it accidentally, to be compatible
521 // with crates depending on them, we can't throw an error here.
522 Target::Field | Target::Arm | Target::MacroDef => {
523 self.inline_attr_str_error_with_macro_def(hir_id, attr, "marker");
527 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
528 attr_span: attr.span,
536 /// Checks if the `#[rustc_must_implement_one_of]` attribute on a `target` is valid. Returns `true` if valid.
537 fn check_rustc_must_implement_one_of(
544 Target::Trait => true,
546 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
547 attr_span: attr.span,
555 /// Checks if the `#[target_feature]` attribute on `item` is valid. Returns `true` if valid.
556 fn check_target_feature(
565 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
566 // FIXME: #[target_feature] was previously erroneously allowed on statements and some
567 // crates used this, so only emit a warning.
568 Target::Statement => {
569 self.tcx.emit_spanned_lint(
573 errors::TargetFeatureOnStatement,
577 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
578 // `#[target_feature]` attribute with just a lint, because we previously
579 // erroneously allowed it and some crates used it accidentally, to be compatible
580 // with crates depending on them, we can't throw an error here.
581 Target::Field | Target::Arm | Target::MacroDef => {
582 self.inline_attr_str_error_with_macro_def(hir_id, attr, "target_feature");
586 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
587 attr_span: attr.span,
589 on_crate: hir_id == CRATE_HIR_ID,
596 /// Checks if the `#[thread_local]` attribute on `item` is valid. Returns `true` if valid.
597 fn check_thread_local(&self, attr: &Attribute, span: Span, target: Target) -> bool {
599 Target::ForeignStatic | Target::Static => true,
601 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToStatic {
602 attr_span: attr.span,
610 fn doc_attr_str_error(&self, meta: &NestedMetaItem, attr_name: &str) {
611 self.tcx.sess.emit_err(errors::DocExpectStr { attr_span: meta.span(), attr_name });
614 fn check_doc_alias_value(
616 meta: &NestedMetaItem,
621 aliases: &mut FxHashMap<String, Span>,
624 let span = meta.name_value_literal_span().unwrap_or_else(|| meta.span());
626 &format!("`#[doc(alias{})]`", if is_list { "(\"...\")" } else { " = \"...\"" });
627 if doc_alias == kw::Empty {
628 tcx.sess.emit_err(errors::DocAliasEmpty { span, attr_str });
632 let doc_alias_str = doc_alias.as_str();
633 if let Some(c) = doc_alias_str
635 .find(|&c| c == '"' || c == '\'' || (c.is_whitespace() && c != ' '))
637 tcx.sess.emit_err(errors::DocAliasBadChar { span, attr_str, char_: c });
640 if doc_alias_str.starts_with(' ') || doc_alias_str.ends_with(' ') {
641 tcx.sess.emit_err(errors::DocAliasStartEnd { span, attr_str });
645 let span = meta.span();
646 if let Some(location) = match target {
648 let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
649 let containing_item = self.tcx.hir().expect_item(parent_def_id);
650 if Target::from_item(containing_item) == Target::Impl {
651 Some("type alias in implementation block")
656 Target::AssocConst => {
657 let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
658 let containing_item = self.tcx.hir().expect_item(parent_def_id);
659 // We can't link to trait impl's consts.
660 let err = "associated constant in trait implementation block";
661 match containing_item.kind {
662 ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => Some(err),
666 // we check the validity of params elsewhere
667 Target::Param => return false,
673 | Target::Impl => Some(target.name()),
683 | Target::ImplTraitPlaceholder
693 | Target::ForeignStatic
695 | Target::GenericParam(..)
698 | Target::ExprField => None,
700 tcx.sess.emit_err(errors::DocAliasBadLocation { span, attr_str, location });
703 let item_name = self.tcx.hir().name(hir_id);
704 if item_name == doc_alias {
705 tcx.sess.emit_err(errors::DocAliasNotAnAlias { span, attr_str });
708 if let Err(entry) = aliases.try_insert(doc_alias_str.to_owned(), span) {
709 self.tcx.emit_spanned_lint(
713 errors::DocAliasDuplicated { first_defn: *entry.entry.get() },
721 meta: &NestedMetaItem,
724 aliases: &mut FxHashMap<String, Span>,
726 if let Some(values) = meta.meta_item_list() {
730 Some(l) => match l.kind {
731 LitKind::Str(s, _) => {
732 if !self.check_doc_alias_value(v, s, hir_id, target, true, aliases) {
739 .emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
744 self.tcx.sess.emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
750 } else if let Some(doc_alias) = meta.value_str() {
751 self.check_doc_alias_value(meta, doc_alias, hir_id, target, false, aliases)
753 self.tcx.sess.emit_err(errors::DocAliasMalformed { span: meta.span() });
758 fn check_doc_keyword(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
759 let doc_keyword = meta.value_str().unwrap_or(kw::Empty);
760 if doc_keyword == kw::Empty {
761 self.doc_attr_str_error(meta, "keyword");
764 match self.tcx.hir().find(hir_id).and_then(|node| match node {
765 hir::Node::Item(item) => Some(&item.kind),
768 Some(ItemKind::Mod(ref module)) => {
769 if !module.item_ids.is_empty() {
770 self.tcx.sess.emit_err(errors::DocKeywordEmptyMod { span: meta.span() });
775 self.tcx.sess.emit_err(errors::DocKeywordNotMod { span: meta.span() });
779 if !rustc_lexer::is_ident(doc_keyword.as_str()) {
780 self.tcx.sess.emit_err(errors::DocKeywordInvalidIdent {
781 span: meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
789 fn check_doc_fake_variadic(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
790 match self.tcx.hir().find(hir_id).and_then(|node| match node {
791 hir::Node::Item(item) => Some(&item.kind),
794 Some(ItemKind::Impl(ref i)) => {
795 let is_valid = matches!(&i.self_ty.kind, hir::TyKind::Tup([_]))
796 || if let hir::TyKind::BareFn(bare_fn_ty) = &i.self_ty.kind {
797 bare_fn_ty.decl.inputs.len() == 1
802 self.tcx.sess.emit_err(errors::DocFakeVariadicNotValid { span: meta.span() });
807 self.tcx.sess.emit_err(errors::DocKeywordOnlyImpl { span: meta.span() });
814 /// Checks `#[doc(inline)]`/`#[doc(no_inline)]` attributes. Returns `true` if valid.
816 /// A doc inlining attribute is invalid if it is applied to a non-`use` item, or
817 /// if there are conflicting attributes for one item.
819 /// `specified_inline` is used to keep track of whether we have
820 /// already seen an inlining attribute for this item.
821 /// If so, `specified_inline` holds the value and the span of
822 /// the first `inline`/`no_inline` attribute.
826 meta: &NestedMetaItem,
829 specified_inline: &mut Option<(bool, Span)>,
831 if target == Target::Use || target == Target::ExternCrate {
832 let do_inline = meta.name_or_empty() == sym::inline;
833 if let Some((prev_inline, prev_span)) = *specified_inline {
834 if do_inline != prev_inline {
835 let mut spans = MultiSpan::from_spans(vec![prev_span, meta.span()]);
836 spans.push_span_label(prev_span, fluent::passes_doc_inline_conflict_first);
837 spans.push_span_label(meta.span(), fluent::passes_doc_inline_conflict_second);
838 self.tcx.sess.emit_err(errors::DocKeywordConflict { spans });
843 *specified_inline = Some((do_inline, meta.span()));
847 self.tcx.emit_spanned_lint(
848 INVALID_DOC_ATTRIBUTES,
851 errors::DocInlineOnlyUse {
852 attr_span: meta.span(),
853 item_span: (attr.style == AttrStyle::Outer)
854 .then(|| self.tcx.hir().span(hir_id)),
861 /// Checks that an attribute is *not* used at the crate level. Returns `true` if valid.
862 fn check_attr_not_crate_level(
864 meta: &NestedMetaItem,
868 if CRATE_HIR_ID == hir_id {
869 self.tcx.sess.emit_err(errors::DocAttrNotCrateLevel { span: meta.span(), attr_name });
875 /// Checks that an attribute is used at the crate level. Returns `true` if valid.
876 fn check_attr_crate_level(
879 meta: &NestedMetaItem,
882 if hir_id != CRATE_HIR_ID {
883 self.tcx.struct_span_lint_hir(
884 INVALID_DOC_ATTRIBUTES,
887 fluent::passes_attr_crate_level,
889 if attr.style == AttrStyle::Outer
890 && self.tcx.hir().get_parent_item(hir_id) == CRATE_OWNER_ID
892 if let Ok(mut src) = self.tcx.sess.source_map().span_to_snippet(attr.span) {
894 err.span_suggestion_verbose(
898 Applicability::MaybeIncorrect,
901 err.span_help(attr.span, fluent::help);
904 err.note(fluent::note);
913 /// Checks that `doc(test(...))` attribute contains only valid attributes. Returns `true` if
915 fn check_test_attr(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
916 let mut is_valid = true;
917 if let Some(metas) = meta.meta_item_list() {
918 for i_meta in metas {
919 match i_meta.name_or_empty() {
920 sym::attr | sym::no_crate_inject => {}
922 self.tcx.emit_spanned_lint(
923 INVALID_DOC_ATTRIBUTES,
926 errors::DocTestUnknown {
927 path: rustc_ast_pretty::pprust::path_to_string(
928 &i_meta.meta_item().unwrap().path,
937 self.tcx.emit_spanned_lint(
938 INVALID_DOC_ATTRIBUTES,
941 errors::DocTestTakesList,
948 /// Check that the `#![doc(cfg_hide(...))]` attribute only contains a list of attributes.
949 /// Returns `true` if valid.
950 fn check_doc_cfg_hide(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
951 if meta.meta_item_list().is_some() {
954 self.tcx.emit_spanned_lint(
955 INVALID_DOC_ATTRIBUTES,
958 errors::DocCfgHideTakesList,
964 /// Runs various checks on `#[doc]` attributes. Returns `true` if valid.
966 /// `specified_inline` should be initialized to `None` and kept for the scope
967 /// of one item. Read the documentation of [`check_doc_inline`] for more information.
969 /// [`check_doc_inline`]: Self::check_doc_inline
975 specified_inline: &mut Option<(bool, Span)>,
976 aliases: &mut FxHashMap<String, Span>,
978 let mut is_valid = true;
980 if let Some(mi) = attr.meta() && let Some(list) = mi.meta_item_list() {
982 if let Some(i_meta) = meta.meta_item() {
983 match i_meta.name_or_empty() {
985 if !self.check_attr_not_crate_level(meta, hir_id, "alias")
986 || !self.check_doc_alias(meta, hir_id, target, aliases) =>
992 if !self.check_attr_not_crate_level(meta, hir_id, "keyword")
993 || !self.check_doc_keyword(meta, hir_id) =>
999 if !self.check_attr_not_crate_level(meta, hir_id, "fake_variadic")
1000 || !self.check_doc_fake_variadic(meta, hir_id) =>
1005 sym::html_favicon_url
1006 | sym::html_logo_url
1007 | sym::html_playground_url
1008 | sym::issue_tracker_base_url
1009 | sym::html_root_url
1010 | sym::html_no_source
1012 if !self.check_attr_crate_level(attr, meta, hir_id) =>
1018 if !self.check_attr_crate_level(attr, meta, hir_id)
1019 || !self.check_doc_cfg_hide(meta, hir_id) =>
1024 sym::inline | sym::no_inline
1025 if !self.check_doc_inline(
1036 // no_default_passes: deprecated
1037 // passes: deprecated
1038 // plugins: removed, but rustdoc warns about it itself
1043 | sym::html_favicon_url
1044 | sym::html_logo_url
1045 | sym::html_no_source
1046 | sym::html_playground_url
1047 | sym::html_root_url
1049 | sym::issue_tracker_base_url
1052 | sym::no_default_passes
1054 | sym::notable_trait
1057 | sym::fake_variadic => {}
1060 if !self.check_test_attr(meta, hir_id) {
1066 if !self.tcx.features().rustdoc_internals {
1067 self.tcx.emit_spanned_lint(
1068 INVALID_DOC_ATTRIBUTES,
1071 errors::DocPrimitive,
1077 let path = rustc_ast_pretty::pprust::path_to_string(&i_meta.path);
1078 if i_meta.has_name(sym::spotlight) {
1079 self.tcx.emit_spanned_lint(
1080 INVALID_DOC_ATTRIBUTES,
1083 errors::DocTestUnknownSpotlight {
1088 } else if i_meta.has_name(sym::include) &&
1089 let Some(value) = i_meta.value_str() {
1090 let applicability = if list.len() == 1 {
1091 Applicability::MachineApplicable
1093 Applicability::MaybeIncorrect
1095 // If there are multiple attributes, the suggestion would suggest
1096 // deleting all of them, which is incorrect.
1097 self.tcx.emit_spanned_lint(
1098 INVALID_DOC_ATTRIBUTES,
1101 errors::DocTestUnknownInclude {
1103 value: value.to_string(),
1104 inner: if attr.style == AttrStyle::Inner { "!" } else { "" },
1105 sugg: (attr.meta().unwrap().span, applicability),
1109 self.tcx.emit_spanned_lint(
1110 INVALID_DOC_ATTRIBUTES,
1113 errors::DocTestUnknownAny { path }
1120 self.tcx.emit_spanned_lint(
1121 INVALID_DOC_ATTRIBUTES,
1134 /// Warns against some misuses of `#[pass_by_value]`
1135 fn check_pass_by_value(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1137 Target::Struct | Target::Enum | Target::TyAlias => true,
1139 self.tcx.sess.emit_err(errors::PassByValue { attr_span: attr.span, span });
1145 fn check_allow_incoherent_impl(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1147 Target::Method(MethodKind::Inherent) => true,
1149 self.tcx.sess.emit_err(errors::AllowIncoherentImpl { attr_span: attr.span, span });
1155 fn check_has_incoherent_inherent_impls(
1162 Target::Trait | Target::Struct | Target::Enum | Target::Union | Target::ForeignTy => {
1168 .emit_err(errors::HasIncoherentInherentImpl { attr_span: attr.span, span });
1174 /// Warns against some misuses of `#[must_use]`
1175 fn check_must_use(&self, hir_id: HirId, attr: &Attribute, target: Target) -> bool {
1184 // `impl Trait` in return position can trip
1185 // `unused_must_use` if `Trait` is marked as
1189 let article = match target {
1194 | Target::Expression
1196 | Target::AssocConst
1197 | Target::AssocTy => "an",
1201 self.tcx.emit_spanned_lint(
1205 errors::MustUseNoEffect { article, target },
1209 // For now, its always valid
1213 /// Checks if `#[must_not_suspend]` is applied to a function. Returns `true` if valid.
1214 fn check_must_not_suspend(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1216 Target::Struct | Target::Enum | Target::Union | Target::Trait => true,
1218 self.tcx.sess.emit_err(errors::MustNotSuspend { attr_span: attr.span, span });
1224 /// Checks if `#[cold]` is applied to a non-function. Returns `true` if valid.
1225 fn check_cold(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1227 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => {}
1228 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1229 // `#[cold]` attribute with just a lint, because we previously
1230 // erroneously allowed it and some crates used it accidentally, to be compatible
1231 // with crates depending on them, we can't throw an error here.
1232 Target::Field | Target::Arm | Target::MacroDef => {
1233 self.inline_attr_str_error_with_macro_def(hir_id, attr, "cold");
1236 // FIXME: #[cold] was previously allowed on non-functions and some crates used
1237 // this, so only emit a warning.
1238 self.tcx.emit_spanned_lint(
1242 errors::Cold { span, on_crate: hir_id == CRATE_HIR_ID },
1248 /// Checks if `#[link]` is applied to an item other than a foreign module.
1249 fn check_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1250 if target == Target::ForeignMod
1251 && let hir::Node::Item(item) = self.tcx.hir().get(hir_id)
1252 && let Item { kind: ItemKind::ForeignMod { abi, .. }, .. } = item
1253 && !matches!(abi, Abi::Rust | Abi::RustIntrinsic | Abi::PlatformIntrinsic)
1258 self.tcx.emit_spanned_lint(
1262 errors::Link { span: (target != Target::ForeignMod).then_some(span) },
1266 /// Checks if `#[link_name]` is applied to an item other than a foreign function or static.
1267 fn check_link_name(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1269 Target::ForeignFn | Target::ForeignStatic => {}
1270 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1271 // `#[link_name]` attribute with just a lint, because we previously
1272 // erroneously allowed it and some crates used it accidentally, to be compatible
1273 // with crates depending on them, we can't throw an error here.
1274 Target::Field | Target::Arm | Target::MacroDef => {
1275 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_name");
1278 // FIXME: #[cold] was previously allowed on non-functions/statics and some crates
1279 // used this, so only emit a warning.
1280 let attr_span = matches!(target, Target::ForeignMod).then_some(attr.span);
1281 if let Some(s) = attr.value_str() {
1282 self.tcx.emit_spanned_lint(
1286 errors::LinkName { span, attr_span, value: s.as_str() },
1289 self.tcx.emit_spanned_lint(
1293 errors::LinkName { span, attr_span, value: "..." },
1300 /// Checks if `#[no_link]` is applied to an `extern crate`. Returns `true` if valid.
1301 fn check_no_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
1303 Target::ExternCrate => true,
1304 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1305 // `#[no_link]` attribute with just a lint, because we previously
1306 // erroneously allowed it and some crates used it accidentally, to be compatible
1307 // with crates depending on them, we can't throw an error here.
1308 Target::Field | Target::Arm | Target::MacroDef => {
1309 self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_link");
1313 self.tcx.sess.emit_err(errors::NoLink { attr_span: attr.span, span });
1319 fn is_impl_item(&self, hir_id: HirId) -> bool {
1320 matches!(self.tcx.hir().get(hir_id), hir::Node::ImplItem(..))
1323 /// Checks if `#[export_name]` is applied to a function or static. Returns `true` if valid.
1324 fn check_export_name(
1332 Target::Static | Target::Fn => true,
1333 Target::Method(..) if self.is_impl_item(hir_id) => true,
1334 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1335 // `#[export_name]` attribute with just a lint, because we previously
1336 // erroneously allowed it and some crates used it accidentally, to be compatible
1337 // with crates depending on them, we can't throw an error here.
1338 Target::Field | Target::Arm | Target::MacroDef => {
1339 self.inline_attr_str_error_with_macro_def(hir_id, attr, "export_name");
1343 self.tcx.sess.emit_err(errors::ExportName { attr_span: attr.span, span });
1349 fn check_rustc_layout_scalar_valid_range(
1355 if target != Target::Struct {
1356 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeNotStruct {
1357 attr_span: attr.span,
1363 let Some(list) = attr.meta_item_list() else {
1367 if matches!(&list[..], &[NestedMetaItem::Lit(MetaItemLit { kind: LitKind::Int(..), .. })]) {
1370 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeArg { attr_span: attr.span });
1375 /// Checks if `#[rustc_legacy_const_generics]` is applied to a function and has a valid argument.
1376 fn check_rustc_legacy_const_generics(
1382 item: Option<ItemLike<'_>>,
1384 let is_function = matches!(target, Target::Fn);
1386 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1387 attr_span: attr.span,
1389 on_crate: hir_id == CRATE_HIR_ID,
1394 let Some(list) = attr.meta_item_list() else {
1395 // The attribute form is validated on AST.
1399 let Some(ItemLike::Item(Item {
1400 kind: ItemKind::Fn(FnSig { decl, .. }, generics, _),
1403 bug!("should be a function item");
1406 for param in generics.params {
1408 hir::GenericParamKind::Const { .. } => {}
1410 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsOnly {
1411 attr_span: attr.span,
1412 param_span: param.span,
1419 if list.len() != generics.params.len() {
1420 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndex {
1421 attr_span: attr.span,
1422 generics_span: generics.span,
1427 let arg_count = decl.inputs.len() as u128 + generics.params.len() as u128;
1428 let mut invalid_args = vec![];
1430 if let Some(LitKind::Int(val, _)) = meta.lit().map(|lit| &lit.kind) {
1431 if *val >= arg_count {
1432 let span = meta.span();
1433 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexExceed {
1435 arg_count: arg_count as usize,
1440 invalid_args.push(meta.span());
1444 if !invalid_args.is_empty() {
1445 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexNegative { invalid_args });
1452 /// Helper function for checking that the provided attribute is only applied to a function or
1454 fn check_applied_to_fn_or_method(
1461 let is_function = matches!(target, Target::Fn | Target::Method(..));
1463 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1464 attr_span: attr.span,
1466 on_crate: hir_id == CRATE_HIR_ID,
1474 /// Checks that the `#[rustc_lint_query_instability]` attribute is only applied to a function
1476 fn check_rustc_lint_query_instability(
1483 self.check_applied_to_fn_or_method(hir_id, attr, span, target)
1486 /// Checks that the `#[rustc_lint_diagnostics]` attribute is only applied to a function or
1488 fn check_rustc_lint_diagnostics(
1495 self.check_applied_to_fn_or_method(hir_id, attr, span, target)
1498 /// Checks that the `#[rustc_lint_opt_ty]` attribute is only applied to a struct.
1499 fn check_rustc_lint_opt_ty(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1501 Target::Struct => true,
1503 self.tcx.sess.emit_err(errors::RustcLintOptTy { attr_span: attr.span, span });
1509 /// Checks that the `#[rustc_lint_opt_deny_field_access]` attribute is only applied to a field.
1510 fn check_rustc_lint_opt_deny_field_access(
1517 Target::Field => true,
1521 .emit_err(errors::RustcLintOptDenyFieldAccess { attr_span: attr.span, span });
1527 /// Checks that the dep-graph debugging attributes are only present when the query-dep-graph
1528 /// option is passed to the compiler.
1529 fn check_rustc_dirty_clean(&self, attr: &Attribute) -> bool {
1530 if self.tcx.sess.opts.unstable_opts.query_dep_graph {
1533 self.tcx.sess.emit_err(errors::RustcDirtyClean { span: attr.span });
1538 /// Checks if `#[link_section]` is applied to a function or static.
1539 fn check_link_section(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1541 Target::Static | Target::Fn | Target::Method(..) => {}
1542 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1543 // `#[link_section]` attribute with just a lint, because we previously
1544 // erroneously allowed it and some crates used it accidentally, to be compatible
1545 // with crates depending on them, we can't throw an error here.
1546 Target::Field | Target::Arm | Target::MacroDef => {
1547 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_section");
1550 // FIXME: #[link_section] was previously allowed on non-functions/statics and some
1551 // crates used this, so only emit a warning.
1552 self.tcx.emit_spanned_lint(
1556 errors::LinkSection { span },
1562 /// Checks if `#[no_mangle]` is applied to a function or static.
1563 fn check_no_mangle(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1565 Target::Static | Target::Fn => {}
1566 Target::Method(..) if self.is_impl_item(hir_id) => {}
1567 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1568 // `#[no_mangle]` attribute with just a lint, because we previously
1569 // erroneously allowed it and some crates used it accidentally, to be compatible
1570 // with crates depending on them, we can't throw an error here.
1571 Target::Field | Target::Arm | Target::MacroDef => {
1572 self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_mangle");
1574 // FIXME: #[no_mangle] was previously allowed on non-functions/statics, this should be an error
1575 // The error should specify that the item that is wrong is specifically a *foreign* fn/static
1576 // otherwise the error seems odd
1577 Target::ForeignFn | Target::ForeignStatic => {
1578 let foreign_item_kind = match target {
1579 Target::ForeignFn => "function",
1580 Target::ForeignStatic => "static",
1581 _ => unreachable!(),
1583 self.tcx.emit_spanned_lint(
1587 errors::NoMangleForeign { span, attr_span: attr.span, foreign_item_kind },
1591 // FIXME: #[no_mangle] was previously allowed on non-functions/statics and some
1592 // crates used this, so only emit a warning.
1593 self.tcx.emit_spanned_lint(
1597 errors::NoMangle { span },
1603 /// Checks if the `#[repr]` attributes on `item` are valid.
1606 attrs: &[Attribute],
1609 item: Option<ItemLike<'_>>,
1612 // Extract the names of all repr hints, e.g., [foo, bar, align] for:
1615 // #[repr(bar, align(8))]
1617 let hints: Vec<_> = attrs
1619 .filter(|attr| attr.has_name(sym::repr))
1620 .filter_map(|attr| attr.meta_item_list())
1624 let mut int_reprs = 0;
1625 let mut is_c = false;
1626 let mut is_simd = false;
1627 let mut is_transparent = false;
1629 for hint in &hints {
1630 if !hint.is_meta_item() {
1631 self.tcx.sess.emit_err(errors::ReprIdent { span: hint.span() });
1635 match hint.name_or_empty() {
1639 Target::Struct | Target::Union | Target::Enum => continue,
1641 self.tcx.sess.emit_err(AttrApplication::StructEnumUnion {
1642 hint_span: hint.span(),
1649 if let (Target::Fn, false) = (target, self.tcx.features().fn_align) {
1651 &self.tcx.sess.parse_sess,
1654 "`repr(align)` attributes on functions are unstable",
1660 Target::Struct | Target::Union | Target::Enum | Target::Fn => continue,
1662 self.tcx.sess.emit_err(AttrApplication::StructEnumFunctionUnion {
1663 hint_span: hint.span(),
1670 if target != Target::Struct && target != Target::Union {
1671 self.tcx.sess.emit_err(AttrApplication::StructUnion {
1672 hint_span: hint.span(),
1681 if target != Target::Struct {
1684 .emit_err(AttrApplication::Struct { hint_span: hint.span(), span });
1689 sym::transparent => {
1690 is_transparent = true;
1692 Target::Struct | Target::Union | Target::Enum => continue,
1694 self.tcx.sess.emit_err(AttrApplication::StructEnumUnion {
1695 hint_span: hint.span(),
1714 if target != Target::Enum {
1717 .emit_err(AttrApplication::Enum { hint_span: hint.span(), span });
1723 self.tcx.sess.emit_err(UnrecognizedReprHint { span: hint.span() });
1729 // Just point at all repr hints if there are any incompatibilities.
1730 // This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
1731 let hint_spans = hints.iter().map(|hint| hint.span());
1733 // Error on repr(transparent, <anything else>).
1734 if is_transparent && hints.len() > 1 {
1735 let hint_spans: Vec<_> = hint_spans.clone().collect();
1738 .emit_err(TransparentIncompatible { hint_spans, target: target.to_string() });
1740 // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
1742 || (is_simd && is_c)
1745 && item.map_or(false, |item| {
1746 if let ItemLike::Item(item) = item {
1747 return is_c_like_enum(item);
1752 self.tcx.emit_spanned_lint(
1753 CONFLICTING_REPR_HINTS,
1755 hint_spans.collect::<Vec<Span>>(),
1756 errors::ReprConflicting,
1761 fn check_used(&self, attrs: &[Attribute], target: Target) {
1762 let mut used_linker_span = None;
1763 let mut used_compiler_span = None;
1764 for attr in attrs.iter().filter(|attr| attr.has_name(sym::used)) {
1765 if target != Target::Static {
1766 self.tcx.sess.emit_err(errors::UsedStatic { span: attr.span });
1768 let inner = attr.meta_item_list();
1769 match inner.as_deref() {
1770 Some([item]) if item.has_name(sym::linker) => {
1771 if used_linker_span.is_none() {
1772 used_linker_span = Some(attr.span);
1775 Some([item]) if item.has_name(sym::compiler) => {
1776 if used_compiler_span.is_none() {
1777 used_compiler_span = Some(attr.span);
1781 // This error case is handled in rustc_hir_analysis::collect.
1784 // Default case (compiler) when arg isn't defined.
1785 if used_compiler_span.is_none() {
1786 used_compiler_span = Some(attr.span);
1791 if let (Some(linker_span), Some(compiler_span)) = (used_linker_span, used_compiler_span) {
1794 .emit_err(errors::UsedCompilerLinker { spans: vec![linker_span, compiler_span] });
1798 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1799 /// (Allows proc_macro functions)
1800 fn check_allow_internal_unstable(
1806 attrs: &[Attribute],
1808 debug!("Checking target: {:?}", target);
1812 if self.tcx.sess.is_proc_macro_attr(attr) {
1813 debug!("Is proc macro attr");
1817 debug!("Is not proc macro attr");
1820 Target::MacroDef => true,
1821 // FIXME(#80564): We permit struct fields and match arms to have an
1822 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1823 // erroneously allowed it and some crates used it accidentally, to be compatible
1824 // with crates depending on them, we can't throw an error here.
1825 Target::Field | Target::Arm => {
1826 self.inline_attr_str_error_without_macro_def(
1829 "allow_internal_unstable",
1836 .emit_err(errors::AllowInternalUnstable { attr_span: attr.span, span });
1842 /// Checks if the items on the `#[debugger_visualizer]` attribute are valid.
1843 fn check_debugger_visualizer(&self, attr: &Attribute, target: Target) -> bool {
1847 self.tcx.sess.emit_err(errors::DebugVisualizerPlacement { span: attr.span });
1852 let Some(hints) = attr.meta_item_list() else {
1853 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1857 let hint = match hints.len() {
1860 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1865 let Some(meta_item) = hint.meta_item() else {
1866 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1870 let visualizer_path = match (meta_item.name_or_empty(), meta_item.value_str()) {
1871 (sym::natvis_file, Some(value)) => value,
1872 (sym::gdb_script_file, Some(value)) => value,
1874 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: meta_item.span });
1880 match resolve_path(&self.tcx.sess.parse_sess, visualizer_path.as_str(), attr.span) {
1888 match std::fs::File::open(&file) {
1891 self.tcx.sess.emit_err(DebugVisualizerUnreadable {
1892 span: meta_item.span,
1901 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1902 /// (Allows proc_macro functions)
1903 fn check_rustc_allow_const_fn_unstable(
1911 Target::Fn | Target::Method(_)
1912 if self.tcx.is_const_fn_raw(self.tcx.hir().local_def_id(hir_id).to_def_id()) =>
1916 // FIXME(#80564): We permit struct fields and match arms to have an
1917 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1918 // erroneously allowed it and some crates used it accidentally, to be compatible
1919 // with crates depending on them, we can't throw an error here.
1920 Target::Field | Target::Arm | Target::MacroDef => {
1921 self.inline_attr_str_error_with_macro_def(hir_id, attr, "allow_internal_unstable");
1927 .emit_err(errors::RustcAllowConstFnUnstable { attr_span: attr.span, span });
1933 fn check_rustc_std_internal_symbol(
1940 Target::Fn | Target::Static => true,
1944 .emit_err(errors::RustcStdInternalSymbol { attr_span: attr.span, span });
1950 /// `#[const_trait]` only applies to traits.
1951 fn check_const_trait(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1953 Target::Trait => true,
1955 self.tcx.sess.emit_err(errors::ConstTrait { attr_span: attr.span });
1961 fn check_stability_promotable(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1963 Target::Expression => {
1964 self.tcx.sess.emit_err(errors::StabilityPromotable { attr_span: attr.span });
1971 fn check_link_ordinal(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1973 Target::ForeignFn | Target::ForeignStatic => true,
1975 self.tcx.sess.emit_err(errors::LinkOrdinal { attr_span: attr.span });
1981 fn check_deprecated(&self, hir_id: HirId, attr: &Attribute, _span: Span, target: Target) {
1983 Target::Closure | Target::Expression | Target::Statement | Target::Arm => {
1984 self.tcx.emit_spanned_lint(
1995 fn check_macro_use(&self, hir_id: HirId, attr: &Attribute, target: Target) {
1996 let name = attr.name_or_empty();
1998 Target::ExternCrate | Target::Mod => {}
2000 self.tcx.emit_spanned_lint(
2004 errors::MacroUse { name },
2010 fn check_macro_export(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2011 if target != Target::MacroDef {
2012 self.tcx.emit_spanned_lint(UNUSED_ATTRIBUTES, hir_id, attr.span, errors::MacroExport);
2016 fn check_plugin_registrar(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2017 if target != Target::Fn {
2018 self.tcx.emit_spanned_lint(
2022 errors::PluginRegistrar,
2027 fn check_unused_attribute(&self, hir_id: HirId, attr: &Attribute) {
2028 // Warn on useless empty attributes.
2029 let note = if matches!(
2030 attr.name_or_empty(),
2039 | sym::target_feature
2040 ) && attr.meta_item_list().map_or(false, |list| list.is_empty())
2042 errors::UnusedNote::EmptyList { name: attr.name_or_empty() }
2044 attr.name_or_empty(),
2045 sym::allow | sym::warn | sym::deny | sym::forbid | sym::expect
2046 ) && let Some(meta) = attr.meta_item_list()
2048 && let Some(item) = meta[0].meta_item()
2049 && let MetaItemKind::NameValue(_) = &item.kind
2050 && item.path == sym::reason
2052 errors::UnusedNote::NoLints { name: attr.name_or_empty() }
2053 } else if attr.name_or_empty() == sym::default_method_body_is_const {
2054 errors::UnusedNote::DefaultMethodBodyConst
2059 self.tcx.emit_spanned_lint(
2063 errors::Unused { attr_span: attr.span, note },
2068 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {
2069 type NestedFilter = nested_filter::OnlyBodies;
2071 fn nested_visit_map(&mut self) -> Self::Map {
2075 fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
2076 // Historically we've run more checks on non-exported than exported macros,
2077 // so this lets us continue to run them while maintaining backwards compatibility.
2078 // In the long run, the checks should be harmonized.
2079 if let ItemKind::Macro(ref macro_def, _) = item.kind {
2080 let def_id = item.owner_id.to_def_id();
2081 if macro_def.macro_rules && !self.tcx.has_attr(def_id, sym::macro_export) {
2082 check_non_exported_macro_for_invalid_attrs(self.tcx, item);
2086 let target = Target::from_item(item);
2087 self.check_attributes(item.hir_id(), item.span, target, Some(ItemLike::Item(item)));
2088 intravisit::walk_item(self, item)
2091 fn visit_generic_param(&mut self, generic_param: &'tcx hir::GenericParam<'tcx>) {
2092 let target = Target::from_generic_param(generic_param);
2093 self.check_attributes(generic_param.hir_id, generic_param.span, target, None);
2094 intravisit::walk_generic_param(self, generic_param)
2097 fn visit_trait_item(&mut self, trait_item: &'tcx TraitItem<'tcx>) {
2098 let target = Target::from_trait_item(trait_item);
2099 self.check_attributes(trait_item.hir_id(), trait_item.span, target, None);
2100 intravisit::walk_trait_item(self, trait_item)
2103 fn visit_field_def(&mut self, struct_field: &'tcx hir::FieldDef<'tcx>) {
2104 self.check_attributes(struct_field.hir_id, struct_field.span, Target::Field, None);
2105 intravisit::walk_field_def(self, struct_field);
2108 fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
2109 self.check_attributes(arm.hir_id, arm.span, Target::Arm, None);
2110 intravisit::walk_arm(self, arm);
2113 fn visit_foreign_item(&mut self, f_item: &'tcx ForeignItem<'tcx>) {
2114 let target = Target::from_foreign_item(f_item);
2115 self.check_attributes(f_item.hir_id(), f_item.span, target, Some(ItemLike::ForeignItem));
2116 intravisit::walk_foreign_item(self, f_item)
2119 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
2120 let target = target_from_impl_item(self.tcx, impl_item);
2121 self.check_attributes(impl_item.hir_id(), impl_item.span, target, None);
2122 intravisit::walk_impl_item(self, impl_item)
2125 fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt<'tcx>) {
2126 // When checking statements ignore expressions, they will be checked later.
2127 if let hir::StmtKind::Local(ref l) = stmt.kind {
2128 self.check_attributes(l.hir_id, stmt.span, Target::Statement, None);
2130 intravisit::walk_stmt(self, stmt)
2133 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
2134 let target = match expr.kind {
2135 hir::ExprKind::Closure { .. } => Target::Closure,
2136 _ => Target::Expression,
2139 self.check_attributes(expr.hir_id, expr.span, target, None);
2140 intravisit::walk_expr(self, expr)
2143 fn visit_expr_field(&mut self, field: &'tcx hir::ExprField<'tcx>) {
2144 self.check_attributes(field.hir_id, field.span, Target::ExprField, None);
2145 intravisit::walk_expr_field(self, field)
2148 fn visit_variant(&mut self, variant: &'tcx hir::Variant<'tcx>) {
2149 self.check_attributes(variant.hir_id, variant.span, Target::Variant, None);
2150 intravisit::walk_variant(self, variant)
2153 fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {
2154 self.check_attributes(param.hir_id, param.span, Target::Param, None);
2156 intravisit::walk_param(self, param);
2159 fn visit_pat_field(&mut self, field: &'tcx hir::PatField<'tcx>) {
2160 self.check_attributes(field.hir_id, field.span, Target::PatField, None);
2161 intravisit::walk_pat_field(self, field);
2165 fn is_c_like_enum(item: &Item<'_>) -> bool {
2166 if let ItemKind::Enum(ref def, _) = item.kind {
2167 for variant in def.variants {
2168 match variant.data {
2169 hir::VariantData::Unit(..) => { /* continue */ }
2179 // FIXME: Fix "Cannot determine resolution" error and remove built-in macros
2181 fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
2182 // Check for builtin attributes at the crate level
2183 // which were unsuccessfully resolved due to cannot determine
2184 // resolution for the attribute macro error.
2185 const ATTRS_TO_CHECK: &[Symbol] = &[
2189 sym::automatically_derived,
2196 sym::global_allocator,
2201 // This function should only be called with crate attributes
2202 // which are inner attributes always but lets check to make sure
2203 if attr.style == AttrStyle::Inner {
2204 for attr_to_check in ATTRS_TO_CHECK {
2205 if attr.has_name(*attr_to_check) {
2206 tcx.sess.emit_err(InvalidAttrAtCrateLevel {
2208 snippet: tcx.sess.source_map().span_to_snippet(attr.span).ok(),
2209 name: *attr_to_check,
2217 fn check_non_exported_macro_for_invalid_attrs(tcx: TyCtxt<'_>, item: &Item<'_>) {
2218 let attrs = tcx.hir().attrs(item.hir_id());
2221 if attr.has_name(sym::inline) {
2222 tcx.sess.emit_err(errors::NonExportedMacroInvalidAttrs { attr_span: attr.span });
2227 fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
2228 let check_attr_visitor = &mut CheckAttrVisitor { tcx };
2229 tcx.hir().visit_item_likes_in_module(module_def_id, check_attr_visitor);
2230 if module_def_id.is_top_level_module() {
2231 check_attr_visitor.check_attributes(CRATE_HIR_ID, DUMMY_SP, Target::Mod, None);
2232 check_invalid_crate_level_attr(tcx, tcx.hir().krate_attrs());
2236 pub(crate) fn provide(providers: &mut Providers) {
2237 *providers = Providers { check_mod_attrs, ..*providers };
2240 fn check_duplicates(
2244 duplicates: AttributeDuplicates,
2245 seen: &mut FxHashMap<Symbol, Span>,
2247 use AttributeDuplicates::*;
2248 if matches!(duplicates, WarnFollowingWordOnly) && !attr.is_word() {
2253 WarnFollowing | FutureWarnFollowing | WarnFollowingWordOnly | FutureWarnPreceding => {
2254 match seen.entry(attr.name_or_empty()) {
2255 Entry::Occupied(mut entry) => {
2256 let (this, other) = if matches!(duplicates, FutureWarnPreceding) {
2257 let to_remove = entry.insert(attr.span);
2258 (to_remove, attr.span)
2260 (attr.span, *entry.get())
2262 tcx.emit_spanned_lint(
2266 errors::UnusedDuplicate {
2271 FutureWarnFollowing | FutureWarnPreceding
2277 Entry::Vacant(entry) => {
2278 entry.insert(attr.span);
2282 ErrorFollowing | ErrorPreceding => match seen.entry(attr.name_or_empty()) {
2283 Entry::Occupied(mut entry) => {
2284 let (this, other) = if matches!(duplicates, ErrorPreceding) {
2285 let to_remove = entry.insert(attr.span);
2286 (to_remove, attr.span)
2288 (attr.span, *entry.get())
2290 tcx.sess.emit_err(errors::UnusedMultiple {
2293 name: attr.name_or_empty(),
2296 Entry::Vacant(entry) => {
2297 entry.insert(attr.span);