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, Lit, LitKind, MetaItemKind, 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::inline => self.check_inline(hir_id, attr, span, target),
86 sym::no_coverage => self.check_no_coverage(hir_id, attr, span, target),
87 sym::non_exhaustive => self.check_non_exhaustive(hir_id, attr, span, target),
88 sym::marker => self.check_marker(hir_id, attr, span, target),
89 sym::rustc_must_implement_one_of => {
90 self.check_rustc_must_implement_one_of(attr, span, target)
92 sym::target_feature => self.check_target_feature(hir_id, attr, span, target),
93 sym::thread_local => self.check_thread_local(attr, span, target),
94 sym::track_caller => {
95 self.check_track_caller(hir_id, attr.span, attrs, span, target)
97 sym::doc => self.check_doc_attrs(
101 &mut specified_inline,
104 sym::no_link => self.check_no_link(hir_id, &attr, span, target),
105 sym::export_name => self.check_export_name(hir_id, &attr, span, target),
106 sym::rustc_layout_scalar_valid_range_start
107 | sym::rustc_layout_scalar_valid_range_end => {
108 self.check_rustc_layout_scalar_valid_range(&attr, span, target)
110 sym::allow_internal_unstable => {
111 self.check_allow_internal_unstable(hir_id, &attr, span, target, &attrs)
113 sym::debugger_visualizer => self.check_debugger_visualizer(&attr, target),
114 sym::rustc_allow_const_fn_unstable => {
115 self.check_rustc_allow_const_fn_unstable(hir_id, &attr, span, target)
117 sym::rustc_std_internal_symbol => {
118 self.check_rustc_std_internal_symbol(&attr, span, target)
120 sym::naked => self.check_naked(hir_id, attr, span, target),
121 sym::rustc_legacy_const_generics => {
122 self.check_rustc_legacy_const_generics(hir_id, &attr, span, target, item)
124 sym::rustc_lint_query_instability => {
125 self.check_rustc_lint_query_instability(hir_id, &attr, span, target)
127 sym::rustc_lint_diagnostics => {
128 self.check_rustc_lint_diagnostics(hir_id, &attr, span, target)
130 sym::rustc_lint_opt_ty => self.check_rustc_lint_opt_ty(&attr, span, target),
131 sym::rustc_lint_opt_deny_field_access => {
132 self.check_rustc_lint_opt_deny_field_access(&attr, span, target)
136 | sym::rustc_if_this_changed
137 | sym::rustc_then_this_would_need => self.check_rustc_dirty_clean(&attr),
138 sym::cmse_nonsecure_entry => {
139 self.check_cmse_nonsecure_entry(hir_id, attr, span, target)
141 sym::collapse_debuginfo => self.check_collapse_debuginfo(attr, span, target),
142 sym::const_trait => self.check_const_trait(attr, span, target),
143 sym::must_not_suspend => self.check_must_not_suspend(&attr, span, target),
144 sym::must_use => self.check_must_use(hir_id, &attr, target),
145 sym::rustc_pass_by_value => self.check_pass_by_value(&attr, span, target),
146 sym::rustc_allow_incoherent_impl => {
147 self.check_allow_incoherent_impl(&attr, span, target)
149 sym::rustc_has_incoherent_inherent_impls => {
150 self.check_has_incoherent_inherent_impls(&attr, span, target)
152 sym::rustc_const_unstable
153 | sym::rustc_const_stable
156 | sym::rustc_allowed_through_unstable_modules
157 | sym::rustc_promotable => self.check_stability_promotable(&attr, span, target),
158 sym::link_ordinal => self.check_link_ordinal(&attr, span, target),
161 is_valid &= attr_is_valid;
164 match attr.name_or_empty() {
165 sym::cold => self.check_cold(hir_id, attr, span, target),
166 sym::link => self.check_link(hir_id, attr, span, target),
167 sym::link_name => self.check_link_name(hir_id, attr, span, target),
168 sym::link_section => self.check_link_section(hir_id, attr, span, target),
169 sym::no_mangle => self.check_no_mangle(hir_id, attr, span, target),
170 sym::deprecated => self.check_deprecated(hir_id, attr, span, target),
171 sym::macro_use | sym::macro_escape => self.check_macro_use(hir_id, attr, target),
172 sym::path => self.check_generic_attr(hir_id, attr, target, Target::Mod),
173 sym::plugin_registrar => self.check_plugin_registrar(hir_id, attr, target),
174 sym::macro_export => self.check_macro_export(hir_id, attr, target),
175 sym::ignore | sym::should_panic | sym::proc_macro_derive => {
176 self.check_generic_attr(hir_id, attr, target, Target::Fn)
178 sym::automatically_derived => {
179 self.check_generic_attr(hir_id, attr, target, Target::Impl)
181 sym::no_implicit_prelude => {
182 self.check_generic_attr(hir_id, attr, target, Target::Mod)
184 sym::rustc_object_lifetime_default => self.check_object_lifetime_default(hir_id),
188 let builtin = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
190 if hir_id != CRATE_HIR_ID {
191 if let Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) =
192 attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name))
195 ast::AttrStyle::Outer => self.tcx.emit_spanned_lint(
199 errors::OuterCrateLevelAttr,
201 ast::AttrStyle::Inner => self.tcx.emit_spanned_lint(
205 errors::InnerCrateLevelAttr,
211 if let Some(BuiltinAttribute { duplicates, .. }) = builtin {
212 check_duplicates(self.tcx, attr, hir_id, *duplicates, &mut seen);
215 self.check_unused_attribute(hir_id, attr)
222 // FIXME(@lcnr): this doesn't belong here.
229 | Target::ForeignStatic
231 self.tcx.ensure().codegen_fn_attrs(self.tcx.hir().local_def_id(hir_id));
234 self.check_repr(attrs, span, target, item, hir_id);
235 self.check_used(attrs, target);
238 fn inline_attr_str_error_with_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
239 self.tcx.emit_spanned_lint(
243 errors::IgnoredAttrWithMacro { sym },
247 fn inline_attr_str_error_without_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
248 self.tcx.emit_spanned_lint(
252 errors::IgnoredAttr { sym },
256 /// Checks if an `#[inline]` is applied to a function or a closure. Returns `true` if valid.
257 fn check_inline(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
261 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
262 Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
263 self.tcx.emit_spanned_lint(
267 errors::IgnoredInlineAttrFnProto,
271 // FIXME(#65833): We permit associated consts to have an `#[inline]` attribute with
272 // just a lint, because we previously erroneously allowed it and some crates used it
273 // accidentally, to be compatible with crates depending on them, we can't throw an
275 Target::AssocConst => {
276 self.tcx.emit_spanned_lint(
280 errors::IgnoredInlineAttrConstants,
284 // FIXME(#80564): Same for fields, arms, and macro defs
285 Target::Field | Target::Arm | Target::MacroDef => {
286 self.inline_attr_str_error_with_macro_def(hir_id, attr, "inline");
290 self.tcx.sess.emit_err(errors::InlineNotFnOrClosure {
291 attr_span: attr.span,
299 /// Checks if a `#[no_coverage]` is applied directly to a function
300 fn check_no_coverage(
308 // no_coverage on function is fine
311 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
313 // function prototypes can't be covered
314 Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
315 self.tcx.emit_spanned_lint(
319 errors::IgnoredNoCoverageFnProto,
324 Target::Mod | Target::ForeignMod | Target::Impl | Target::Trait => {
325 self.tcx.emit_spanned_lint(
329 errors::IgnoredNoCoveragePropagate,
334 Target::Expression | Target::Statement | Target::Arm => {
335 self.tcx.emit_spanned_lint(
339 errors::IgnoredNoCoverageFnDefn,
345 self.tcx.sess.emit_err(errors::IgnoredNoCoverageNotCoverable {
346 attr_span: attr.span,
354 fn check_generic_attr(
359 allowed_target: Target,
361 if target != allowed_target {
362 self.tcx.emit_spanned_lint(
367 attr_name: attr.name_or_empty(),
368 target_name: allowed_target.name().replace(" ", "_"),
374 /// Checks if `#[naked]` is applied to a function definition.
375 fn check_naked(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
378 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
379 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
380 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
381 // erroneously allowed it and some crates used it accidentally, to be compatible
382 // with crates depending on them, we can't throw an error here.
383 Target::Field | Target::Arm | Target::MacroDef => {
384 self.inline_attr_str_error_with_macro_def(hir_id, attr, "naked");
388 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
389 attr_span: attr.span,
391 on_crate: hir_id == CRATE_HIR_ID,
398 /// Checks if `#[cmse_nonsecure_entry]` is applied to a function definition.
399 fn check_cmse_nonsecure_entry(
408 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
410 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
411 attr_span: attr.span,
413 on_crate: hir_id == CRATE_HIR_ID,
420 /// Debugging aid for `object_lifetime_default` query.
421 fn check_object_lifetime_default(&self, hir_id: HirId) {
423 if let Some(generics) = tcx.hir().get_generics(tcx.hir().local_def_id(hir_id)) {
424 for p in generics.params {
425 let hir::GenericParamKind::Type { .. } = p.kind else { continue };
426 let param_id = tcx.hir().local_def_id(p.hir_id);
427 let default = tcx.object_lifetime_default(param_id);
428 let repr = match default {
429 ObjectLifetimeDefault::Empty => "BaseDefault".to_owned(),
430 ObjectLifetimeDefault::Static => "'static".to_owned(),
431 ObjectLifetimeDefault::Param(def_id) => tcx.item_name(def_id).to_string(),
432 ObjectLifetimeDefault::Ambiguous => "Ambiguous".to_owned(),
434 tcx.sess.emit_err(ObjectLifetimeErr { span: p.span, repr });
439 /// Checks if `#[collapse_debuginfo]` is applied to a macro.
440 fn check_collapse_debuginfo(&self, attr: &Attribute, span: Span, target: Target) -> bool {
442 Target::MacroDef => true,
446 .emit_err(errors::CollapseDebuginfo { attr_span: attr.span, defn_span: span });
452 /// Checks if a `#[track_caller]` is applied to a non-naked function. Returns `true` if valid.
453 fn check_track_caller(
462 _ if attrs.iter().any(|attr| attr.has_name(sym::naked)) => {
463 self.tcx.sess.emit_err(errors::NakedTrackedCaller { attr_span });
466 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => true,
467 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
468 // `#[track_caller]` attribute with just a lint, because we previously
469 // erroneously allowed it and some crates used it accidentally, to be compatible
470 // with crates depending on them, we can't throw an error here.
471 Target::Field | Target::Arm | Target::MacroDef => {
473 self.inline_attr_str_error_with_macro_def(hir_id, attr, "track_caller");
478 self.tcx.sess.emit_err(errors::TrackedCallerWrongLocation {
481 on_crate: hir_id == CRATE_HIR_ID,
488 /// Checks if the `#[non_exhaustive]` attribute on an `item` is valid. Returns `true` if valid.
489 fn check_non_exhaustive(
497 Target::Struct | Target::Enum | Target::Variant => true,
498 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
499 // `#[non_exhaustive]` attribute with just a lint, because we previously
500 // erroneously allowed it and some crates used it accidentally, to be compatible
501 // with crates depending on them, we can't throw an error here.
502 Target::Field | Target::Arm | Target::MacroDef => {
503 self.inline_attr_str_error_with_macro_def(hir_id, attr, "non_exhaustive");
507 self.tcx.sess.emit_err(errors::NonExhaustiveWrongLocation {
508 attr_span: attr.span,
516 /// Checks if the `#[marker]` attribute on an `item` is valid. Returns `true` if valid.
517 fn check_marker(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
519 Target::Trait => true,
520 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
521 // `#[marker]` attribute with just a lint, because we previously
522 // erroneously allowed it and some crates used it accidentally, to be compatible
523 // with crates depending on them, we can't throw an error here.
524 Target::Field | Target::Arm | Target::MacroDef => {
525 self.inline_attr_str_error_with_macro_def(hir_id, attr, "marker");
529 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
530 attr_span: attr.span,
538 /// Checks if the `#[rustc_must_implement_one_of]` attribute on a `target` is valid. Returns `true` if valid.
539 fn check_rustc_must_implement_one_of(
546 Target::Trait => true,
548 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
549 attr_span: attr.span,
557 /// Checks if the `#[target_feature]` attribute on `item` is valid. Returns `true` if valid.
558 fn check_target_feature(
567 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
568 // FIXME: #[target_feature] was previously erroneously allowed on statements and some
569 // crates used this, so only emit a warning.
570 Target::Statement => {
571 self.tcx.emit_spanned_lint(
575 errors::TargetFeatureOnStatement,
579 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
580 // `#[target_feature]` attribute with just a lint, because we previously
581 // erroneously allowed it and some crates used it accidentally, to be compatible
582 // with crates depending on them, we can't throw an error here.
583 Target::Field | Target::Arm | Target::MacroDef => {
584 self.inline_attr_str_error_with_macro_def(hir_id, attr, "target_feature");
588 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
589 attr_span: attr.span,
591 on_crate: hir_id == CRATE_HIR_ID,
598 /// Checks if the `#[thread_local]` attribute on `item` is valid. Returns `true` if valid.
599 fn check_thread_local(&self, attr: &Attribute, span: Span, target: Target) -> bool {
601 Target::ForeignStatic | Target::Static => true,
603 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToStatic {
604 attr_span: attr.span,
612 fn doc_attr_str_error(&self, meta: &NestedMetaItem, attr_name: &str) {
613 self.tcx.sess.emit_err(errors::DocExpectStr { attr_span: meta.span(), attr_name });
616 fn check_doc_alias_value(
618 meta: &NestedMetaItem,
623 aliases: &mut FxHashMap<String, Span>,
626 let span = meta.name_value_literal_span().unwrap_or_else(|| meta.span());
628 &format!("`#[doc(alias{})]`", if is_list { "(\"...\")" } else { " = \"...\"" });
629 if doc_alias == kw::Empty {
630 tcx.sess.emit_err(errors::DocAliasEmpty { span, attr_str });
634 let doc_alias_str = doc_alias.as_str();
635 if let Some(c) = doc_alias_str
637 .find(|&c| c == '"' || c == '\'' || (c.is_whitespace() && c != ' '))
639 tcx.sess.emit_err(errors::DocAliasBadChar { span, attr_str, char_: c });
642 if doc_alias_str.starts_with(' ') || doc_alias_str.ends_with(' ') {
643 tcx.sess.emit_err(errors::DocAliasStartEnd { span, attr_str });
647 let span = meta.span();
648 if let Some(location) = match target {
650 let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
651 let containing_item = self.tcx.hir().expect_item(parent_def_id);
652 if Target::from_item(containing_item) == Target::Impl {
653 Some("type alias in implementation block")
658 Target::AssocConst => {
659 let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
660 let containing_item = self.tcx.hir().expect_item(parent_def_id);
661 // We can't link to trait impl's consts.
662 let err = "associated constant in trait implementation block";
663 match containing_item.kind {
664 ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => Some(err),
668 // we check the validity of params elsewhere
669 Target::Param => return false,
675 | Target::Impl => Some(target.name()),
685 | Target::ImplTraitPlaceholder
695 | Target::ForeignStatic
697 | Target::GenericParam(..)
700 | Target::ExprField => None,
702 tcx.sess.emit_err(errors::DocAliasBadLocation { span, attr_str, location });
705 let item_name = self.tcx.hir().name(hir_id);
706 if item_name == doc_alias {
707 tcx.sess.emit_err(errors::DocAliasNotAnAlias { span, attr_str });
710 if let Err(entry) = aliases.try_insert(doc_alias_str.to_owned(), span) {
711 self.tcx.emit_spanned_lint(
715 errors::DocAliasDuplicated { first_defn: *entry.entry.get() },
723 meta: &NestedMetaItem,
726 aliases: &mut FxHashMap<String, Span>,
728 if let Some(values) = meta.meta_item_list() {
732 Some(l) => match l.kind {
733 LitKind::Str(s, _) => {
734 if !self.check_doc_alias_value(v, s, hir_id, target, true, aliases) {
741 .emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
746 self.tcx.sess.emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
752 } else if let Some(doc_alias) = meta.value_str() {
753 self.check_doc_alias_value(meta, doc_alias, hir_id, target, false, aliases)
755 self.tcx.sess.emit_err(errors::DocAliasMalformed { span: meta.span() });
760 fn check_doc_keyword(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
761 let doc_keyword = meta.value_str().unwrap_or(kw::Empty);
762 if doc_keyword == kw::Empty {
763 self.doc_attr_str_error(meta, "keyword");
766 match self.tcx.hir().find(hir_id).and_then(|node| match node {
767 hir::Node::Item(item) => Some(&item.kind),
770 Some(ItemKind::Mod(ref module)) => {
771 if !module.item_ids.is_empty() {
772 self.tcx.sess.emit_err(errors::DocKeywordEmptyMod { span: meta.span() });
777 self.tcx.sess.emit_err(errors::DocKeywordNotMod { span: meta.span() });
781 if !rustc_lexer::is_ident(doc_keyword.as_str()) {
782 self.tcx.sess.emit_err(errors::DocKeywordInvalidIdent {
783 span: meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
791 fn check_doc_fake_variadic(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
792 match self.tcx.hir().find(hir_id).and_then(|node| match node {
793 hir::Node::Item(item) => Some(&item.kind),
796 Some(ItemKind::Impl(ref i)) => {
797 let is_valid = matches!(&i.self_ty.kind, hir::TyKind::Tup([_]))
798 || if let hir::TyKind::BareFn(bare_fn_ty) = &i.self_ty.kind {
799 bare_fn_ty.decl.inputs.len() == 1
804 self.tcx.sess.emit_err(errors::DocFakeVariadicNotValid { span: meta.span() });
809 self.tcx.sess.emit_err(errors::DocKeywordOnlyImpl { span: meta.span() });
816 /// Checks `#[doc(inline)]`/`#[doc(no_inline)]` attributes. Returns `true` if valid.
818 /// A doc inlining attribute is invalid if it is applied to a non-`use` item, or
819 /// if there are conflicting attributes for one item.
821 /// `specified_inline` is used to keep track of whether we have
822 /// already seen an inlining attribute for this item.
823 /// If so, `specified_inline` holds the value and the span of
824 /// the first `inline`/`no_inline` attribute.
828 meta: &NestedMetaItem,
831 specified_inline: &mut Option<(bool, Span)>,
833 if target == Target::Use || target == Target::ExternCrate {
834 let do_inline = meta.name_or_empty() == sym::inline;
835 if let Some((prev_inline, prev_span)) = *specified_inline {
836 if do_inline != prev_inline {
837 let mut spans = MultiSpan::from_spans(vec![prev_span, meta.span()]);
838 spans.push_span_label(prev_span, fluent::passes_doc_inline_conflict_first);
839 spans.push_span_label(meta.span(), fluent::passes_doc_inline_conflict_second);
840 self.tcx.sess.emit_err(errors::DocKeywordConflict { spans });
845 *specified_inline = Some((do_inline, meta.span()));
849 self.tcx.emit_spanned_lint(
850 INVALID_DOC_ATTRIBUTES,
853 errors::DocInlineOnlyUse {
854 attr_span: meta.span(),
855 item_span: (attr.style == AttrStyle::Outer)
856 .then(|| self.tcx.hir().span(hir_id)),
863 /// Checks that an attribute is *not* used at the crate level. Returns `true` if valid.
864 fn check_attr_not_crate_level(
866 meta: &NestedMetaItem,
870 if CRATE_HIR_ID == hir_id {
871 self.tcx.sess.emit_err(errors::DocAttrNotCrateLevel { span: meta.span(), attr_name });
877 /// Checks that an attribute is used at the crate level. Returns `true` if valid.
878 fn check_attr_crate_level(
881 meta: &NestedMetaItem,
884 if hir_id != CRATE_HIR_ID {
885 self.tcx.struct_span_lint_hir(
886 INVALID_DOC_ATTRIBUTES,
889 fluent::passes_attr_crate_level,
891 if attr.style == AttrStyle::Outer
892 && self.tcx.hir().get_parent_item(hir_id) == CRATE_OWNER_ID
894 if let Ok(mut src) = self.tcx.sess.source_map().span_to_snippet(attr.span) {
896 err.span_suggestion_verbose(
900 Applicability::MaybeIncorrect,
903 err.span_help(attr.span, fluent::help);
906 err.note(fluent::note);
915 /// Checks that `doc(test(...))` attribute contains only valid attributes. Returns `true` if
917 fn check_test_attr(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
918 let mut is_valid = true;
919 if let Some(metas) = meta.meta_item_list() {
920 for i_meta in metas {
921 match i_meta.name_or_empty() {
922 sym::attr | sym::no_crate_inject => {}
924 self.tcx.emit_spanned_lint(
925 INVALID_DOC_ATTRIBUTES,
928 errors::DocTestUnknown {
929 path: rustc_ast_pretty::pprust::path_to_string(
930 &i_meta.meta_item().unwrap().path,
939 self.tcx.emit_spanned_lint(
940 INVALID_DOC_ATTRIBUTES,
943 errors::DocTestTakesList,
950 /// Check that the `#![doc(cfg_hide(...))]` attribute only contains a list of attributes.
951 /// Returns `true` if valid.
952 fn check_doc_cfg_hide(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
953 if meta.meta_item_list().is_some() {
956 self.tcx.emit_spanned_lint(
957 INVALID_DOC_ATTRIBUTES,
960 errors::DocCfgHideTakesList,
966 /// Runs various checks on `#[doc]` attributes. Returns `true` if valid.
968 /// `specified_inline` should be initialized to `None` and kept for the scope
969 /// of one item. Read the documentation of [`check_doc_inline`] for more information.
971 /// [`check_doc_inline`]: Self::check_doc_inline
977 specified_inline: &mut Option<(bool, Span)>,
978 aliases: &mut FxHashMap<String, Span>,
980 let mut is_valid = true;
982 if let Some(mi) = attr.meta() && let Some(list) = mi.meta_item_list() {
984 if let Some(i_meta) = meta.meta_item() {
985 match i_meta.name_or_empty() {
987 if !self.check_attr_not_crate_level(meta, hir_id, "alias")
988 || !self.check_doc_alias(meta, hir_id, target, aliases) =>
994 if !self.check_attr_not_crate_level(meta, hir_id, "keyword")
995 || !self.check_doc_keyword(meta, hir_id) =>
1001 if !self.check_attr_not_crate_level(meta, hir_id, "fake_variadic")
1002 || !self.check_doc_fake_variadic(meta, hir_id) =>
1007 sym::html_favicon_url
1008 | sym::html_logo_url
1009 | sym::html_playground_url
1010 | sym::issue_tracker_base_url
1011 | sym::html_root_url
1012 | sym::html_no_source
1014 if !self.check_attr_crate_level(attr, meta, hir_id) =>
1020 if !self.check_attr_crate_level(attr, meta, hir_id)
1021 || !self.check_doc_cfg_hide(meta, hir_id) =>
1026 sym::inline | sym::no_inline
1027 if !self.check_doc_inline(
1038 // no_default_passes: deprecated
1039 // passes: deprecated
1040 // plugins: removed, but rustdoc warns about it itself
1045 | sym::html_favicon_url
1046 | sym::html_logo_url
1047 | sym::html_no_source
1048 | sym::html_playground_url
1049 | sym::html_root_url
1051 | sym::issue_tracker_base_url
1054 | sym::no_default_passes
1056 | sym::notable_trait
1059 | sym::fake_variadic => {}
1062 if !self.check_test_attr(meta, hir_id) {
1068 if !self.tcx.features().rustdoc_internals {
1069 self.tcx.emit_spanned_lint(
1070 INVALID_DOC_ATTRIBUTES,
1073 errors::DocPrimitive,
1079 let path = rustc_ast_pretty::pprust::path_to_string(&i_meta.path);
1080 if i_meta.has_name(sym::spotlight) {
1081 self.tcx.emit_spanned_lint(
1082 INVALID_DOC_ATTRIBUTES,
1085 errors::DocTestUnknownSpotlight {
1090 } else if i_meta.has_name(sym::include) &&
1091 let Some(value) = i_meta.value_str() {
1092 let applicability = if list.len() == 1 {
1093 Applicability::MachineApplicable
1095 Applicability::MaybeIncorrect
1097 // If there are multiple attributes, the suggestion would suggest
1098 // deleting all of them, which is incorrect.
1099 self.tcx.emit_spanned_lint(
1100 INVALID_DOC_ATTRIBUTES,
1103 errors::DocTestUnknownInclude {
1105 value: value.to_string(),
1106 inner: (attr.style == AttrStyle::Inner)
1109 sugg: (attr.meta().unwrap().span, applicability),
1113 self.tcx.emit_spanned_lint(
1114 INVALID_DOC_ATTRIBUTES,
1117 errors::DocTestUnknownAny { path }
1124 self.tcx.emit_spanned_lint(
1125 INVALID_DOC_ATTRIBUTES,
1138 /// Warns against some misuses of `#[pass_by_value]`
1139 fn check_pass_by_value(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1141 Target::Struct | Target::Enum | Target::TyAlias => true,
1143 self.tcx.sess.emit_err(errors::PassByValue { attr_span: attr.span, span });
1149 fn check_allow_incoherent_impl(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1151 Target::Method(MethodKind::Inherent) => true,
1153 self.tcx.sess.emit_err(errors::AllowIncoherentImpl { attr_span: attr.span, span });
1159 fn check_has_incoherent_inherent_impls(
1166 Target::Trait | Target::Struct | Target::Enum | Target::Union | Target::ForeignTy => {
1172 .emit_err(errors::HasIncoherentInherentImpl { attr_span: attr.span, span });
1178 /// Warns against some misuses of `#[must_use]`
1179 fn check_must_use(&self, hir_id: HirId, attr: &Attribute, target: Target) -> bool {
1188 // `impl Trait` in return position can trip
1189 // `unused_must_use` if `Trait` is marked as
1193 let article = match target {
1198 | Target::Expression
1200 | Target::AssocConst
1201 | Target::AssocTy => "an",
1205 self.tcx.emit_spanned_lint(
1209 errors::MustUseNoEffect { article, target },
1213 // For now, its always valid
1217 /// Checks if `#[must_not_suspend]` is applied to a function. Returns `true` if valid.
1218 fn check_must_not_suspend(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1220 Target::Struct | Target::Enum | Target::Union | Target::Trait => true,
1222 self.tcx.sess.emit_err(errors::MustNotSuspend { attr_span: attr.span, span });
1228 /// Checks if `#[cold]` is applied to a non-function. Returns `true` if valid.
1229 fn check_cold(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1231 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => {}
1232 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1233 // `#[cold]` attribute with just a lint, because we previously
1234 // erroneously allowed it and some crates used it accidentally, to be compatible
1235 // with crates depending on them, we can't throw an error here.
1236 Target::Field | Target::Arm | Target::MacroDef => {
1237 self.inline_attr_str_error_with_macro_def(hir_id, attr, "cold");
1240 // FIXME: #[cold] was previously allowed on non-functions and some crates used
1241 // this, so only emit a warning.
1242 self.tcx.emit_spanned_lint(
1246 errors::Cold { span, on_crate: hir_id == CRATE_HIR_ID },
1252 /// Checks if `#[link]` is applied to an item other than a foreign module.
1253 fn check_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1254 if target == Target::ForeignMod
1255 && let hir::Node::Item(item) = self.tcx.hir().get(hir_id)
1256 && let Item { kind: ItemKind::ForeignMod { abi, .. }, .. } = item
1257 && !matches!(abi, Abi::Rust | Abi::RustIntrinsic | Abi::PlatformIntrinsic)
1262 self.tcx.emit_spanned_lint(
1266 errors::Link { span: (target != Target::ForeignMod).then_some(span) },
1270 /// Checks if `#[link_name]` is applied to an item other than a foreign function or static.
1271 fn check_link_name(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1273 Target::ForeignFn | Target::ForeignStatic => {}
1274 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1275 // `#[link_name]` attribute with just a lint, because we previously
1276 // erroneously allowed it and some crates used it accidentally, to be compatible
1277 // with crates depending on them, we can't throw an error here.
1278 Target::Field | Target::Arm | Target::MacroDef => {
1279 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_name");
1282 // FIXME: #[cold] was previously allowed on non-functions/statics and some crates
1283 // used this, so only emit a warning.
1284 let attr_span = matches!(target, Target::ForeignMod).then_some(attr.span);
1285 if let Some(s) = attr.value_str() {
1286 self.tcx.emit_spanned_lint(
1290 errors::LinkName { span, attr_span, value: s.as_str() },
1293 self.tcx.emit_spanned_lint(
1297 errors::LinkName { span, attr_span, value: "..." },
1304 /// Checks if `#[no_link]` is applied to an `extern crate`. Returns `true` if valid.
1305 fn check_no_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
1307 Target::ExternCrate => true,
1308 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1309 // `#[no_link]` attribute with just a lint, because we previously
1310 // erroneously allowed it and some crates used it accidentally, to be compatible
1311 // with crates depending on them, we can't throw an error here.
1312 Target::Field | Target::Arm | Target::MacroDef => {
1313 self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_link");
1317 self.tcx.sess.emit_err(errors::NoLink { attr_span: attr.span, span });
1323 fn is_impl_item(&self, hir_id: HirId) -> bool {
1324 matches!(self.tcx.hir().get(hir_id), hir::Node::ImplItem(..))
1327 /// Checks if `#[export_name]` is applied to a function or static. Returns `true` if valid.
1328 fn check_export_name(
1336 Target::Static | Target::Fn => true,
1337 Target::Method(..) if self.is_impl_item(hir_id) => true,
1338 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1339 // `#[export_name]` attribute with just a lint, because we previously
1340 // erroneously allowed it and some crates used it accidentally, to be compatible
1341 // with crates depending on them, we can't throw an error here.
1342 Target::Field | Target::Arm | Target::MacroDef => {
1343 self.inline_attr_str_error_with_macro_def(hir_id, attr, "export_name");
1347 self.tcx.sess.emit_err(errors::ExportName { attr_span: attr.span, span });
1353 fn check_rustc_layout_scalar_valid_range(
1359 if target != Target::Struct {
1360 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeNotStruct {
1361 attr_span: attr.span,
1367 let Some(list) = attr.meta_item_list() else {
1371 if matches!(&list[..], &[NestedMetaItem::Literal(Lit { kind: LitKind::Int(..), .. })]) {
1374 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeArg { attr_span: attr.span });
1379 /// Checks if `#[rustc_legacy_const_generics]` is applied to a function and has a valid argument.
1380 fn check_rustc_legacy_const_generics(
1386 item: Option<ItemLike<'_>>,
1388 let is_function = matches!(target, Target::Fn);
1390 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1391 attr_span: attr.span,
1393 on_crate: hir_id == CRATE_HIR_ID,
1398 let Some(list) = attr.meta_item_list() else {
1399 // The attribute form is validated on AST.
1403 let Some(ItemLike::Item(Item {
1404 kind: ItemKind::Fn(FnSig { decl, .. }, generics, _),
1407 bug!("should be a function item");
1410 for param in generics.params {
1412 hir::GenericParamKind::Const { .. } => {}
1414 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsOnly {
1415 attr_span: attr.span,
1416 param_span: param.span,
1423 if list.len() != generics.params.len() {
1424 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndex {
1425 attr_span: attr.span,
1426 generics_span: generics.span,
1431 let arg_count = decl.inputs.len() as u128 + generics.params.len() as u128;
1432 let mut invalid_args = vec![];
1434 if let Some(LitKind::Int(val, _)) = meta.literal().map(|lit| &lit.kind) {
1435 if *val >= arg_count {
1436 let span = meta.span();
1437 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexExceed {
1439 arg_count: arg_count as usize,
1444 invalid_args.push(meta.span());
1448 if !invalid_args.is_empty() {
1449 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexNegative { invalid_args });
1456 /// Helper function for checking that the provided attribute is only applied to a function or
1458 fn check_applied_to_fn_or_method(
1465 let is_function = matches!(target, Target::Fn | Target::Method(..));
1467 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1468 attr_span: attr.span,
1470 on_crate: hir_id == CRATE_HIR_ID,
1478 /// Checks that the `#[rustc_lint_query_instability]` attribute is only applied to a function
1480 fn check_rustc_lint_query_instability(
1487 self.check_applied_to_fn_or_method(hir_id, attr, span, target)
1490 /// Checks that the `#[rustc_lint_diagnostics]` attribute is only applied to a function or
1492 fn check_rustc_lint_diagnostics(
1499 self.check_applied_to_fn_or_method(hir_id, attr, span, target)
1502 /// Checks that the `#[rustc_lint_opt_ty]` attribute is only applied to a struct.
1503 fn check_rustc_lint_opt_ty(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1505 Target::Struct => true,
1507 self.tcx.sess.emit_err(errors::RustcLintOptTy { attr_span: attr.span, span });
1513 /// Checks that the `#[rustc_lint_opt_deny_field_access]` attribute is only applied to a field.
1514 fn check_rustc_lint_opt_deny_field_access(
1521 Target::Field => true,
1525 .emit_err(errors::RustcLintOptDenyFieldAccess { attr_span: attr.span, span });
1531 /// Checks that the dep-graph debugging attributes are only present when the query-dep-graph
1532 /// option is passed to the compiler.
1533 fn check_rustc_dirty_clean(&self, attr: &Attribute) -> bool {
1534 if self.tcx.sess.opts.unstable_opts.query_dep_graph {
1537 self.tcx.sess.emit_err(errors::RustcDirtyClean { span: attr.span });
1542 /// Checks if `#[link_section]` is applied to a function or static.
1543 fn check_link_section(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1545 Target::Static | Target::Fn | Target::Method(..) => {}
1546 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1547 // `#[link_section]` attribute with just a lint, because we previously
1548 // erroneously allowed it and some crates used it accidentally, to be compatible
1549 // with crates depending on them, we can't throw an error here.
1550 Target::Field | Target::Arm | Target::MacroDef => {
1551 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_section");
1554 // FIXME: #[link_section] was previously allowed on non-functions/statics and some
1555 // crates used this, so only emit a warning.
1556 self.tcx.emit_spanned_lint(
1560 errors::LinkSection { span },
1566 /// Checks if `#[no_mangle]` is applied to a function or static.
1567 fn check_no_mangle(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1569 Target::Static | Target::Fn => {}
1570 Target::Method(..) if self.is_impl_item(hir_id) => {}
1571 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1572 // `#[no_mangle]` attribute with just a lint, because we previously
1573 // erroneously allowed it and some crates used it accidentally, to be compatible
1574 // with crates depending on them, we can't throw an error here.
1575 Target::Field | Target::Arm | Target::MacroDef => {
1576 self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_mangle");
1578 // FIXME: #[no_mangle] was previously allowed on non-functions/statics, this should be an error
1579 // The error should specify that the item that is wrong is specifically a *foreign* fn/static
1580 // otherwise the error seems odd
1581 Target::ForeignFn | Target::ForeignStatic => {
1582 let foreign_item_kind = match target {
1583 Target::ForeignFn => "function",
1584 Target::ForeignStatic => "static",
1585 _ => unreachable!(),
1587 self.tcx.emit_spanned_lint(
1591 errors::NoMangleForeign { span, attr_span: attr.span, foreign_item_kind },
1595 // FIXME: #[no_mangle] was previously allowed on non-functions/statics and some
1596 // crates used this, so only emit a warning.
1597 self.tcx.emit_spanned_lint(
1601 errors::NoMangle { span },
1607 /// Checks if the `#[repr]` attributes on `item` are valid.
1610 attrs: &[Attribute],
1613 item: Option<ItemLike<'_>>,
1616 // Extract the names of all repr hints, e.g., [foo, bar, align] for:
1619 // #[repr(bar, align(8))]
1621 let hints: Vec<_> = attrs
1623 .filter(|attr| attr.has_name(sym::repr))
1624 .filter_map(|attr| attr.meta_item_list())
1628 let mut int_reprs = 0;
1629 let mut is_c = false;
1630 let mut is_simd = false;
1631 let mut is_transparent = false;
1633 for hint in &hints {
1634 if !hint.is_meta_item() {
1635 self.tcx.sess.emit_err(errors::ReprIdent { span: hint.span() });
1639 match hint.name_or_empty() {
1643 Target::Struct | Target::Union | Target::Enum => continue,
1645 self.tcx.sess.emit_err(AttrApplication::StructEnumUnion {
1646 hint_span: hint.span(),
1653 if let (Target::Fn, false) = (target, self.tcx.features().fn_align) {
1655 &self.tcx.sess.parse_sess,
1658 "`repr(align)` attributes on functions are unstable",
1664 Target::Struct | Target::Union | Target::Enum | Target::Fn => continue,
1666 self.tcx.sess.emit_err(AttrApplication::StructEnumFunctionUnion {
1667 hint_span: hint.span(),
1674 if target != Target::Struct && target != Target::Union {
1675 self.tcx.sess.emit_err(AttrApplication::StructUnion {
1676 hint_span: hint.span(),
1685 if target != Target::Struct {
1688 .emit_err(AttrApplication::Struct { hint_span: hint.span(), span });
1693 sym::transparent => {
1694 is_transparent = true;
1696 Target::Struct | Target::Union | Target::Enum => continue,
1698 self.tcx.sess.emit_err(AttrApplication::StructEnumUnion {
1699 hint_span: hint.span(),
1718 if target != Target::Enum {
1721 .emit_err(AttrApplication::Enum { hint_span: hint.span(), span });
1727 self.tcx.sess.emit_err(UnrecognizedReprHint { span: hint.span() });
1733 // Just point at all repr hints if there are any incompatibilities.
1734 // This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
1735 let hint_spans = hints.iter().map(|hint| hint.span());
1737 // Error on repr(transparent, <anything else>).
1738 if is_transparent && hints.len() > 1 {
1739 let hint_spans: Vec<_> = hint_spans.clone().collect();
1742 .emit_err(TransparentIncompatible { hint_spans, target: target.to_string() });
1744 // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
1746 || (is_simd && is_c)
1749 && item.map_or(false, |item| {
1750 if let ItemLike::Item(item) = item {
1751 return is_c_like_enum(item);
1756 self.tcx.emit_spanned_lint(
1757 CONFLICTING_REPR_HINTS,
1759 hint_spans.collect::<Vec<Span>>(),
1760 errors::ReprConflicting,
1765 fn check_used(&self, attrs: &[Attribute], target: Target) {
1766 let mut used_linker_span = None;
1767 let mut used_compiler_span = None;
1768 for attr in attrs.iter().filter(|attr| attr.has_name(sym::used)) {
1769 if target != Target::Static {
1770 self.tcx.sess.emit_err(errors::UsedStatic { span: attr.span });
1772 let inner = attr.meta_item_list();
1773 match inner.as_deref() {
1774 Some([item]) if item.has_name(sym::linker) => {
1775 if used_linker_span.is_none() {
1776 used_linker_span = Some(attr.span);
1779 Some([item]) if item.has_name(sym::compiler) => {
1780 if used_compiler_span.is_none() {
1781 used_compiler_span = Some(attr.span);
1785 // This error case is handled in rustc_hir_analysis::collect.
1788 // Default case (compiler) when arg isn't defined.
1789 if used_compiler_span.is_none() {
1790 used_compiler_span = Some(attr.span);
1795 if let (Some(linker_span), Some(compiler_span)) = (used_linker_span, used_compiler_span) {
1798 .emit_err(errors::UsedCompilerLinker { spans: vec![linker_span, compiler_span] });
1802 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1803 /// (Allows proc_macro functions)
1804 fn check_allow_internal_unstable(
1810 attrs: &[Attribute],
1812 debug!("Checking target: {:?}", target);
1816 if self.tcx.sess.is_proc_macro_attr(attr) {
1817 debug!("Is proc macro attr");
1821 debug!("Is not proc macro attr");
1824 Target::MacroDef => true,
1825 // FIXME(#80564): We permit struct fields and match arms to have an
1826 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1827 // erroneously allowed it and some crates used it accidentally, to be compatible
1828 // with crates depending on them, we can't throw an error here.
1829 Target::Field | Target::Arm => {
1830 self.inline_attr_str_error_without_macro_def(
1833 "allow_internal_unstable",
1840 .emit_err(errors::AllowInternalUnstable { attr_span: attr.span, span });
1846 /// Checks if the items on the `#[debugger_visualizer]` attribute are valid.
1847 fn check_debugger_visualizer(&self, attr: &Attribute, target: Target) -> bool {
1851 self.tcx.sess.emit_err(errors::DebugVisualizerPlacement { span: attr.span });
1856 let Some(hints) = attr.meta_item_list() else {
1857 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1861 let hint = match hints.len() {
1864 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1869 let Some(meta_item) = hint.meta_item() else {
1870 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1874 let visualizer_path = match (meta_item.name_or_empty(), meta_item.value_str()) {
1875 (sym::natvis_file, Some(value)) => value,
1876 (sym::gdb_script_file, Some(value)) => value,
1878 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: meta_item.span });
1884 match resolve_path(&self.tcx.sess.parse_sess, visualizer_path.as_str(), attr.span) {
1892 match std::fs::File::open(&file) {
1895 self.tcx.sess.emit_err(DebugVisualizerUnreadable {
1896 span: meta_item.span,
1905 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1906 /// (Allows proc_macro functions)
1907 fn check_rustc_allow_const_fn_unstable(
1915 Target::Fn | Target::Method(_)
1916 if self.tcx.is_const_fn_raw(self.tcx.hir().local_def_id(hir_id).to_def_id()) =>
1920 // FIXME(#80564): We permit struct fields and match arms to have an
1921 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1922 // erroneously allowed it and some crates used it accidentally, to be compatible
1923 // with crates depending on them, we can't throw an error here.
1924 Target::Field | Target::Arm | Target::MacroDef => {
1925 self.inline_attr_str_error_with_macro_def(hir_id, attr, "allow_internal_unstable");
1931 .emit_err(errors::RustcAllowConstFnUnstable { attr_span: attr.span, span });
1937 fn check_rustc_std_internal_symbol(
1944 Target::Fn | Target::Static => true,
1948 .emit_err(errors::RustcStdInternalSymbol { attr_span: attr.span, span });
1954 /// `#[const_trait]` only applies to traits.
1955 fn check_const_trait(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1957 Target::Trait => true,
1959 self.tcx.sess.emit_err(errors::ConstTrait { attr_span: attr.span });
1965 fn check_stability_promotable(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1967 Target::Expression => {
1968 self.tcx.sess.emit_err(errors::StabilityPromotable { attr_span: attr.span });
1975 fn check_link_ordinal(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1977 Target::ForeignFn | Target::ForeignStatic => true,
1979 self.tcx.sess.emit_err(errors::LinkOrdinal { attr_span: attr.span });
1985 fn check_deprecated(&self, hir_id: HirId, attr: &Attribute, _span: Span, target: Target) {
1987 Target::Closure | Target::Expression | Target::Statement | Target::Arm => {
1988 self.tcx.emit_spanned_lint(
1999 fn check_macro_use(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2000 let name = attr.name_or_empty();
2002 Target::ExternCrate | Target::Mod => {}
2004 self.tcx.emit_spanned_lint(
2008 errors::MacroUse { name },
2014 fn check_macro_export(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2015 if target != Target::MacroDef {
2016 self.tcx.emit_spanned_lint(UNUSED_ATTRIBUTES, hir_id, attr.span, errors::MacroExport);
2020 fn check_plugin_registrar(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2021 if target != Target::Fn {
2022 self.tcx.emit_spanned_lint(
2026 errors::PluginRegistrar,
2031 fn check_unused_attribute(&self, hir_id: HirId, attr: &Attribute) {
2032 // Warn on useless empty attributes.
2033 let note = if matches!(
2034 attr.name_or_empty(),
2043 | sym::target_feature
2044 ) && attr.meta_item_list().map_or(false, |list| list.is_empty())
2046 errors::UnusedNote::EmptyList { name: attr.name_or_empty() }
2048 attr.name_or_empty(),
2049 sym::allow | sym::warn | sym::deny | sym::forbid | sym::expect
2050 ) && let Some(meta) = attr.meta_item_list()
2052 && let Some(item) = meta[0].meta_item()
2053 && let MetaItemKind::NameValue(_) = &item.kind
2054 && item.path == sym::reason
2056 errors::UnusedNote::NoLints { name: attr.name_or_empty() }
2057 } else if attr.name_or_empty() == sym::default_method_body_is_const {
2058 errors::UnusedNote::DefaultMethodBodyConst
2063 self.tcx.emit_spanned_lint(
2067 errors::Unused { attr_span: attr.span, note },
2072 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {
2073 type NestedFilter = nested_filter::OnlyBodies;
2075 fn nested_visit_map(&mut self) -> Self::Map {
2079 fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
2080 // Historically we've run more checks on non-exported than exported macros,
2081 // so this lets us continue to run them while maintaining backwards compatibility.
2082 // In the long run, the checks should be harmonized.
2083 if let ItemKind::Macro(ref macro_def, _) = item.kind {
2084 let def_id = item.owner_id.to_def_id();
2085 if macro_def.macro_rules && !self.tcx.has_attr(def_id, sym::macro_export) {
2086 check_non_exported_macro_for_invalid_attrs(self.tcx, item);
2090 let target = Target::from_item(item);
2091 self.check_attributes(item.hir_id(), item.span, target, Some(ItemLike::Item(item)));
2092 intravisit::walk_item(self, item)
2095 fn visit_generic_param(&mut self, generic_param: &'tcx hir::GenericParam<'tcx>) {
2096 let target = Target::from_generic_param(generic_param);
2097 self.check_attributes(generic_param.hir_id, generic_param.span, target, None);
2098 intravisit::walk_generic_param(self, generic_param)
2101 fn visit_trait_item(&mut self, trait_item: &'tcx TraitItem<'tcx>) {
2102 let target = Target::from_trait_item(trait_item);
2103 self.check_attributes(trait_item.hir_id(), trait_item.span, target, None);
2104 intravisit::walk_trait_item(self, trait_item)
2107 fn visit_field_def(&mut self, struct_field: &'tcx hir::FieldDef<'tcx>) {
2108 self.check_attributes(struct_field.hir_id, struct_field.span, Target::Field, None);
2109 intravisit::walk_field_def(self, struct_field);
2112 fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
2113 self.check_attributes(arm.hir_id, arm.span, Target::Arm, None);
2114 intravisit::walk_arm(self, arm);
2117 fn visit_foreign_item(&mut self, f_item: &'tcx ForeignItem<'tcx>) {
2118 let target = Target::from_foreign_item(f_item);
2119 self.check_attributes(f_item.hir_id(), f_item.span, target, Some(ItemLike::ForeignItem));
2120 intravisit::walk_foreign_item(self, f_item)
2123 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
2124 let target = target_from_impl_item(self.tcx, impl_item);
2125 self.check_attributes(impl_item.hir_id(), impl_item.span, target, None);
2126 intravisit::walk_impl_item(self, impl_item)
2129 fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt<'tcx>) {
2130 // When checking statements ignore expressions, they will be checked later.
2131 if let hir::StmtKind::Local(ref l) = stmt.kind {
2132 self.check_attributes(l.hir_id, stmt.span, Target::Statement, None);
2134 intravisit::walk_stmt(self, stmt)
2137 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
2138 let target = match expr.kind {
2139 hir::ExprKind::Closure { .. } => Target::Closure,
2140 _ => Target::Expression,
2143 self.check_attributes(expr.hir_id, expr.span, target, None);
2144 intravisit::walk_expr(self, expr)
2147 fn visit_expr_field(&mut self, field: &'tcx hir::ExprField<'tcx>) {
2148 self.check_attributes(field.hir_id, field.span, Target::ExprField, None);
2149 intravisit::walk_expr_field(self, field)
2152 fn visit_variant(&mut self, variant: &'tcx hir::Variant<'tcx>) {
2153 self.check_attributes(variant.id, variant.span, Target::Variant, None);
2154 intravisit::walk_variant(self, variant)
2157 fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {
2158 self.check_attributes(param.hir_id, param.span, Target::Param, None);
2160 intravisit::walk_param(self, param);
2163 fn visit_pat_field(&mut self, field: &'tcx hir::PatField<'tcx>) {
2164 self.check_attributes(field.hir_id, field.span, Target::PatField, None);
2165 intravisit::walk_pat_field(self, field);
2169 fn is_c_like_enum(item: &Item<'_>) -> bool {
2170 if let ItemKind::Enum(ref def, _) = item.kind {
2171 for variant in def.variants {
2172 match variant.data {
2173 hir::VariantData::Unit(..) => { /* continue */ }
2183 // FIXME: Fix "Cannot determine resolution" error and remove built-in macros
2185 fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
2186 // Check for builtin attributes at the crate level
2187 // which were unsuccessfully resolved due to cannot determine
2188 // resolution for the attribute macro error.
2189 const ATTRS_TO_CHECK: &[Symbol] = &[
2193 sym::automatically_derived,
2200 sym::global_allocator,
2205 // This function should only be called with crate attributes
2206 // which are inner attributes always but lets check to make sure
2207 if attr.style == AttrStyle::Inner {
2208 for attr_to_check in ATTRS_TO_CHECK {
2209 if attr.has_name(*attr_to_check) {
2210 tcx.sess.emit_err(InvalidAttrAtCrateLevel {
2212 snippet: tcx.sess.source_map().span_to_snippet(attr.span).ok(),
2213 name: *attr_to_check,
2221 fn check_non_exported_macro_for_invalid_attrs(tcx: TyCtxt<'_>, item: &Item<'_>) {
2222 let attrs = tcx.hir().attrs(item.hir_id());
2225 if attr.has_name(sym::inline) {
2226 tcx.sess.emit_err(errors::NonExportedMacroInvalidAttrs { attr_span: attr.span });
2231 fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
2232 let check_attr_visitor = &mut CheckAttrVisitor { tcx };
2233 tcx.hir().visit_item_likes_in_module(module_def_id, check_attr_visitor);
2234 if module_def_id.is_top_level_module() {
2235 check_attr_visitor.check_attributes(CRATE_HIR_ID, DUMMY_SP, Target::Mod, None);
2236 check_invalid_crate_level_attr(tcx, tcx.hir().krate_attrs());
2240 pub(crate) fn provide(providers: &mut Providers) {
2241 *providers = Providers { check_mod_attrs, ..*providers };
2244 fn check_duplicates(
2248 duplicates: AttributeDuplicates,
2249 seen: &mut FxHashMap<Symbol, Span>,
2251 use AttributeDuplicates::*;
2252 if matches!(duplicates, WarnFollowingWordOnly) && !attr.is_word() {
2257 WarnFollowing | FutureWarnFollowing | WarnFollowingWordOnly | FutureWarnPreceding => {
2258 match seen.entry(attr.name_or_empty()) {
2259 Entry::Occupied(mut entry) => {
2260 let (this, other) = if matches!(duplicates, FutureWarnPreceding) {
2261 let to_remove = entry.insert(attr.span);
2262 (to_remove, attr.span)
2264 (attr.span, *entry.get())
2266 tcx.emit_spanned_lint(
2270 errors::UnusedDuplicate {
2275 FutureWarnFollowing | FutureWarnPreceding
2281 Entry::Vacant(entry) => {
2282 entry.insert(attr.span);
2286 ErrorFollowing | ErrorPreceding => match seen.entry(attr.name_or_empty()) {
2287 Entry::Occupied(mut entry) => {
2288 let (this, other) = if matches!(duplicates, ErrorPreceding) {
2289 let to_remove = entry.insert(attr.span);
2290 (to_remove, attr.span)
2292 (attr.span, *entry.get())
2294 tcx.sess.emit_err(errors::UnusedMultiple {
2297 name: attr.name_or_empty(),
2300 Entry::Vacant(entry) => {
2301 entry.insert(attr.span);