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 use rustc_ast::{ast, AttrStyle, Attribute, Lit, LitKind, MetaItemKind, NestedMetaItem};
9 use rustc_data_structures::fx::FxHashMap;
10 use rustc_errors::{fluent, struct_span_err, Applicability, MultiSpan};
11 use rustc_expand::base::resolve_path;
12 use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
14 use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID};
15 use rustc_hir::intravisit::{self, Visitor};
16 use rustc_hir::{self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID};
17 use rustc_hir::{MethodKind, Target};
18 use rustc_middle::hir::nested_filter;
19 use rustc_middle::middle::resolve_lifetime::ObjectLifetimeDefault;
20 use rustc_middle::ty::query::Providers;
21 use rustc_middle::ty::TyCtxt;
22 use rustc_session::lint::builtin::{
23 CONFLICTING_REPR_HINTS, INVALID_DOC_ATTRIBUTES, UNUSED_ATTRIBUTES,
25 use rustc_session::parse::feature_err;
26 use rustc_span::symbol::{kw, sym, Symbol};
27 use rustc_span::{Span, DUMMY_SP};
28 use rustc_target::spec::abi::Abi;
29 use std::collections::hash_map::Entry;
31 pub(crate) fn target_from_impl_item<'tcx>(
33 impl_item: &hir::ImplItem<'_>,
35 match impl_item.kind {
36 hir::ImplItemKind::Const(..) => Target::AssocConst,
37 hir::ImplItemKind::Fn(..) => {
38 let parent_hir_id = tcx.hir().get_parent_item(impl_item.hir_id());
39 let containing_item = tcx.hir().expect_item(parent_hir_id);
40 let containing_impl_is_for_trait = match &containing_item.kind {
41 hir::ItemKind::Impl(impl_) => impl_.of_trait.is_some(),
42 _ => bug!("parent of an ImplItem must be an Impl"),
44 if containing_impl_is_for_trait {
45 Target::Method(MethodKind::Trait { body: true })
47 Target::Method(MethodKind::Inherent)
50 hir::ImplItemKind::TyAlias(..) => Target::AssocTy,
54 #[derive(Clone, Copy)]
56 Item(&'tcx Item<'tcx>),
60 struct CheckAttrVisitor<'tcx> {
64 impl CheckAttrVisitor<'_> {
65 /// Checks any attribute.
71 item: Option<ItemLike<'_>>,
73 let mut doc_aliases = FxHashMap::default();
74 let mut is_valid = true;
75 let mut specified_inline = None;
76 let mut seen = FxHashMap::default();
77 let attrs = self.tcx.hir().attrs(hir_id);
79 let attr_is_valid = match attr.name_or_empty() {
80 sym::inline => self.check_inline(hir_id, attr, span, target),
81 sym::no_coverage => self.check_no_coverage(hir_id, attr, span, target),
82 sym::non_exhaustive => self.check_non_exhaustive(hir_id, attr, span, target),
83 sym::marker => self.check_marker(hir_id, attr, span, target),
84 sym::rustc_must_implement_one_of => {
85 self.check_rustc_must_implement_one_of(attr, span, target)
87 sym::target_feature => self.check_target_feature(hir_id, attr, span, target),
88 sym::thread_local => self.check_thread_local(attr, span, target),
89 sym::track_caller => {
90 self.check_track_caller(hir_id, attr.span, attrs, span, target)
92 sym::doc => self.check_doc_attrs(
96 &mut specified_inline,
99 sym::no_link => self.check_no_link(hir_id, &attr, span, target),
100 sym::export_name => self.check_export_name(hir_id, &attr, span, target),
101 sym::rustc_layout_scalar_valid_range_start
102 | sym::rustc_layout_scalar_valid_range_end => {
103 self.check_rustc_layout_scalar_valid_range(&attr, span, target)
105 sym::allow_internal_unstable => {
106 self.check_allow_internal_unstable(hir_id, &attr, span, target, &attrs)
108 sym::debugger_visualizer => self.check_debugger_visualizer(&attr, target),
109 sym::rustc_allow_const_fn_unstable => {
110 self.check_rustc_allow_const_fn_unstable(hir_id, &attr, span, target)
112 sym::rustc_std_internal_symbol => {
113 self.check_rustc_std_internal_symbol(&attr, span, target)
115 sym::naked => self.check_naked(hir_id, attr, span, target),
116 sym::rustc_legacy_const_generics => {
117 self.check_rustc_legacy_const_generics(&attr, span, target, item)
119 sym::rustc_lint_query_instability => {
120 self.check_rustc_lint_query_instability(&attr, span, target)
122 sym::rustc_lint_diagnostics => {
123 self.check_rustc_lint_diagnostics(&attr, span, target)
125 sym::rustc_lint_opt_ty => self.check_rustc_lint_opt_ty(&attr, span, target),
126 sym::rustc_lint_opt_deny_field_access => {
127 self.check_rustc_lint_opt_deny_field_access(&attr, span, target)
131 | sym::rustc_if_this_changed
132 | sym::rustc_then_this_would_need => self.check_rustc_dirty_clean(&attr),
133 sym::cmse_nonsecure_entry => self.check_cmse_nonsecure_entry(attr, span, target),
134 sym::const_trait => self.check_const_trait(attr, span, target),
135 sym::must_not_suspend => self.check_must_not_suspend(&attr, span, target),
136 sym::must_use => self.check_must_use(hir_id, &attr, span, target),
137 sym::rustc_pass_by_value => self.check_pass_by_value(&attr, span, target),
138 sym::rustc_allow_incoherent_impl => {
139 self.check_allow_incoherent_impl(&attr, span, target)
141 sym::rustc_has_incoherent_inherent_impls => {
142 self.check_has_incoherent_inherent_impls(&attr, span, target)
144 sym::rustc_const_unstable
145 | sym::rustc_const_stable
148 | sym::rustc_allowed_through_unstable_modules
149 | sym::rustc_promotable => self.check_stability_promotable(&attr, span, target),
150 sym::link_ordinal => self.check_link_ordinal(&attr, span, target),
153 is_valid &= attr_is_valid;
156 match attr.name_or_empty() {
157 sym::cold => self.check_cold(hir_id, attr, span, target),
158 sym::link => self.check_link(hir_id, attr, span, target),
159 sym::link_name => self.check_link_name(hir_id, attr, span, target),
160 sym::link_section => self.check_link_section(hir_id, attr, span, target),
161 sym::no_mangle => self.check_no_mangle(hir_id, attr, span, target),
162 sym::deprecated => self.check_deprecated(hir_id, attr, span, target),
163 sym::macro_use | sym::macro_escape => self.check_macro_use(hir_id, attr, target),
164 sym::path => self.check_generic_attr(hir_id, attr, target, &[Target::Mod]),
165 sym::plugin_registrar => self.check_plugin_registrar(hir_id, attr, target),
166 sym::macro_export => self.check_macro_export(hir_id, attr, target),
167 sym::ignore | sym::should_panic | sym::proc_macro_derive => {
168 self.check_generic_attr(hir_id, attr, target, &[Target::Fn])
170 sym::automatically_derived => {
171 self.check_generic_attr(hir_id, attr, target, &[Target::Impl])
173 sym::no_implicit_prelude => {
174 self.check_generic_attr(hir_id, attr, target, &[Target::Mod])
176 sym::rustc_object_lifetime_default => {
177 self.check_object_lifetime_default(hir_id, span)
182 let builtin = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
184 if hir_id != CRATE_HIR_ID {
185 if let Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) =
186 attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name))
189 ast::AttrStyle::Outer => self.tcx.emit_spanned_lint(
193 errors::OuterCrateLevelAttr,
195 ast::AttrStyle::Inner => self.tcx.emit_spanned_lint(
199 errors::InnerCrateLevelAttr,
205 if let Some(BuiltinAttribute { duplicates, .. }) = builtin {
206 check_duplicates(self.tcx, attr, hir_id, *duplicates, &mut seen);
209 self.check_unused_attribute(hir_id, attr)
216 // FIXME(@lcnr): this doesn't belong here.
223 | Target::ForeignStatic
225 self.tcx.ensure().codegen_fn_attrs(self.tcx.hir().local_def_id(hir_id));
228 self.check_repr(attrs, span, target, item, hir_id);
229 self.check_used(attrs, target);
232 fn inline_attr_str_error_with_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
233 self.tcx.emit_spanned_lint(
237 errors::IgnoredAttrWithMacro { sym },
241 fn inline_attr_str_error_without_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
242 self.tcx.emit_spanned_lint(
246 errors::IgnoredAttr { sym },
250 /// Checks if an `#[inline]` is applied to a function or a closure. Returns `true` if valid.
251 fn check_inline(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
255 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
256 Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
257 self.tcx.emit_spanned_lint(
261 errors::IgnoredInlineAttrFnProto,
265 // FIXME(#65833): We permit associated consts to have an `#[inline]` attribute with
266 // just a lint, because we previously erroneously allowed it and some crates used it
267 // accidentally, to to be compatible with crates depending on them, we can't throw an
269 Target::AssocConst => {
270 self.tcx.emit_spanned_lint(
274 errors::IgnoredInlineAttrConstants,
278 // FIXME(#80564): Same for fields, arms, and macro defs
279 Target::Field | Target::Arm | Target::MacroDef => {
280 self.inline_attr_str_error_with_macro_def(hir_id, attr, "inline");
284 self.tcx.sess.emit_err(errors::InlineNotFnOrClosure {
285 attr_span: attr.span,
293 /// Checks if a `#[no_coverage]` is applied directly to a function
294 fn check_no_coverage(
302 // no_coverage on function is fine
305 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
307 // function prototypes can't be covered
308 Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
309 self.tcx.emit_spanned_lint(
313 errors::IgnoredNoCoverageFnProto,
318 Target::Mod | Target::ForeignMod | Target::Impl | Target::Trait => {
319 self.tcx.emit_spanned_lint(
323 errors::IgnoredNoCoveragePropagate,
328 Target::Expression | Target::Statement | Target::Arm => {
329 self.tcx.emit_spanned_lint(
333 errors::IgnoredNoCoverageFnDefn,
339 self.tcx.sess.emit_err(errors::IgnoredNoCoverageNotCoverable {
340 attr_span: attr.span,
348 fn check_generic_attr(
353 allowed_targets: &[Target],
355 if !allowed_targets.iter().any(|t| t == &target) {
356 let name = attr.name_or_empty();
357 let mut i = allowed_targets.iter();
359 let b = i.next().map_or_else(String::new, |t| t.to_string() + "s");
360 let supported_names = i.enumerate().fold(b, |mut b, (i, allowed_target)| {
361 if allowed_targets.len() > 2 && i == allowed_targets.len() - 2 {
362 b.push_str(", and ");
363 } else if allowed_targets.len() == 2 && i == allowed_targets.len() - 2 {
369 b.push_str(&(allowed_target.to_string() + "s"));
372 self.tcx.struct_span_lint_hir(UNUSED_ATTRIBUTES, hir_id, attr.span, |lint| {
373 lint.build(&format!("`#[{name}]` only has an effect on {}", supported_names))
379 /// Checks if `#[naked]` is applied to a function definition.
380 fn check_naked(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
383 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
384 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
385 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
386 // erroneously allowed it and some crates used it accidentally, to to be compatible
387 // with crates depending on them, we can't throw an error here.
388 Target::Field | Target::Arm | Target::MacroDef => {
389 self.inline_attr_str_error_with_macro_def(hir_id, attr, "naked");
393 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
394 attr_span: attr.span,
402 /// Checks if `#[cmse_nonsecure_entry]` is applied to a function definition.
403 fn check_cmse_nonsecure_entry(&self, attr: &Attribute, span: Span, target: Target) -> bool {
406 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
408 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
409 attr_span: attr.span,
417 /// Debugging aid for `object_lifetime_default` query.
418 fn check_object_lifetime_default(&self, hir_id: HirId, span: Span) {
420 if let Some(generics) = tcx.hir().get_generics(tcx.hir().local_def_id(hir_id)) {
421 let object_lifetime_default_reprs: String = generics
425 let param_id = tcx.hir().local_def_id(p.hir_id);
426 let default = tcx.object_lifetime_default(param_id)?;
428 ObjectLifetimeDefault::Empty => "BaseDefault".to_owned(),
429 ObjectLifetimeDefault::Static => "'static".to_owned(),
430 ObjectLifetimeDefault::Param(def_id) => tcx.item_name(def_id).to_string(),
431 ObjectLifetimeDefault::Ambiguous => "Ambiguous".to_owned(),
434 .collect::<Vec<String>>()
437 tcx.sess.span_err(span, &object_lifetime_default_reprs);
441 /// Checks if a `#[track_caller]` is applied to a non-naked function. Returns `true` if valid.
442 fn check_track_caller(
451 _ if attrs.iter().any(|attr| attr.has_name(sym::naked)) => {
452 self.tcx.sess.emit_err(errors::NakedTrackedCaller { attr_span });
455 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => true,
456 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
457 // `#[track_caller]` attribute with just a lint, because we previously
458 // erroneously allowed it and some crates used it accidentally, to to be compatible
459 // with crates depending on them, we can't throw an error here.
460 Target::Field | Target::Arm | Target::MacroDef => {
462 self.inline_attr_str_error_with_macro_def(hir_id, attr, "track_caller");
469 .emit_err(errors::TrackedCallerWrongLocation { attr_span, defn_span: span });
475 /// Checks if the `#[non_exhaustive]` attribute on an `item` is valid. Returns `true` if valid.
476 fn check_non_exhaustive(
484 Target::Struct | Target::Enum | Target::Variant => true,
485 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
486 // `#[non_exhaustive]` attribute with just a lint, because we previously
487 // erroneously allowed it and some crates used it accidentally, to to be compatible
488 // with crates depending on them, we can't throw an error here.
489 Target::Field | Target::Arm | Target::MacroDef => {
490 self.inline_attr_str_error_with_macro_def(hir_id, attr, "non_exhaustive");
494 self.tcx.sess.emit_err(errors::NonExhaustiveWrongLocation {
495 attr_span: attr.span,
503 /// Checks if the `#[marker]` attribute on an `item` is valid. Returns `true` if valid.
504 fn check_marker(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
506 Target::Trait => true,
507 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
508 // `#[marker]` attribute with just a lint, because we previously
509 // erroneously allowed it and some crates used it accidentally, to to be compatible
510 // with crates depending on them, we can't throw an error here.
511 Target::Field | Target::Arm | Target::MacroDef => {
512 self.inline_attr_str_error_with_macro_def(hir_id, attr, "marker");
516 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
517 attr_span: attr.span,
525 /// Checks if the `#[rustc_must_implement_one_of]` attribute on a `target` is valid. Returns `true` if valid.
526 fn check_rustc_must_implement_one_of(
533 Target::Trait => true,
535 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
536 attr_span: attr.span,
544 /// Checks if the `#[target_feature]` attribute on `item` is valid. Returns `true` if valid.
545 fn check_target_feature(
554 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
555 // FIXME: #[target_feature] was previously erroneously allowed on statements and some
556 // crates used this, so only emit a warning.
557 Target::Statement => {
558 self.tcx.emit_spanned_lint(
562 errors::TargetFeatureOnStatement,
566 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
567 // `#[target_feature]` attribute with just a lint, because we previously
568 // erroneously allowed it and some crates used it accidentally, to to be compatible
569 // with crates depending on them, we can't throw an error here.
570 Target::Field | Target::Arm | Target::MacroDef => {
571 self.inline_attr_str_error_with_macro_def(hir_id, attr, "target_feature");
575 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
576 attr_span: attr.span,
584 /// Checks if the `#[thread_local]` attribute on `item` is valid. Returns `true` if valid.
585 fn check_thread_local(&self, attr: &Attribute, span: Span, target: Target) -> bool {
587 Target::ForeignStatic | Target::Static => true,
589 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToStatic {
590 attr_span: attr.span,
598 fn doc_attr_str_error(&self, meta: &NestedMetaItem, attr_name: &str) {
599 self.tcx.sess.emit_err(errors::DocExpectStr { attr_span: meta.span(), attr_name });
602 fn check_doc_alias_value(
604 meta: &NestedMetaItem,
609 aliases: &mut FxHashMap<String, Span>,
612 let span = meta.name_value_literal_span().unwrap_or_else(|| meta.span());
614 &format!("`#[doc(alias{})]`", if is_list { "(\"...\")" } else { " = \"...\"" });
615 if doc_alias == kw::Empty {
616 tcx.sess.emit_err(errors::DocAliasEmpty { span, attr_str });
620 let doc_alias_str = doc_alias.as_str();
621 if let Some(c) = doc_alias_str
623 .find(|&c| c == '"' || c == '\'' || (c.is_whitespace() && c != ' '))
625 tcx.sess.emit_err(errors::DocAliasBadChar { span, attr_str, char_: c });
628 if doc_alias_str.starts_with(' ') || doc_alias_str.ends_with(' ') {
629 tcx.sess.emit_err(errors::DocAliasStartEnd { span, attr_str });
633 let span = meta.span();
634 if let Some(location) = match target {
636 let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
637 let containing_item = self.tcx.hir().expect_item(parent_hir_id);
638 if Target::from_item(containing_item) == Target::Impl {
639 Some("type alias in implementation block")
644 Target::AssocConst => {
645 let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
646 let containing_item = self.tcx.hir().expect_item(parent_hir_id);
647 // We can't link to trait impl's consts.
648 let err = "associated constant in trait implementation block";
649 match containing_item.kind {
650 ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => Some(err),
654 // we check the validity of params elsewhere
655 Target::Param => return false,
661 | Target::Impl => Some(target.name()),
680 | Target::ForeignStatic
682 | Target::GenericParam(..)
685 | Target::ExprField => None,
687 tcx.sess.emit_err(errors::DocAliasBadLocation { span, attr_str, location });
690 let item_name = self.tcx.hir().name(hir_id);
691 if item_name == doc_alias {
692 tcx.sess.emit_err(errors::DocAliasNotAnAlias { span, attr_str });
695 if let Err(entry) = aliases.try_insert(doc_alias_str.to_owned(), span) {
696 self.tcx.emit_spanned_lint(
700 errors::DocAliasDuplicated { first_defn: *entry.entry.get() },
708 meta: &NestedMetaItem,
711 aliases: &mut FxHashMap<String, Span>,
713 if let Some(values) = meta.meta_item_list() {
717 Some(l) => match l.kind {
718 LitKind::Str(s, _) => {
719 if !self.check_doc_alias_value(v, s, hir_id, target, true, aliases) {
726 .emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
731 self.tcx.sess.emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
737 } else if let Some(doc_alias) = meta.value_str() {
738 self.check_doc_alias_value(meta, doc_alias, hir_id, target, false, aliases)
740 self.tcx.sess.emit_err(errors::DocAliasMalformed { span: meta.span() });
745 fn check_doc_keyword(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
746 let doc_keyword = meta.value_str().unwrap_or(kw::Empty);
747 if doc_keyword == kw::Empty {
748 self.doc_attr_str_error(meta, "keyword");
751 match self.tcx.hir().find(hir_id).and_then(|node| match node {
752 hir::Node::Item(item) => Some(&item.kind),
755 Some(ItemKind::Mod(ref module)) => {
756 if !module.item_ids.is_empty() {
757 self.tcx.sess.emit_err(errors::DocKeywordEmptyMod { span: meta.span() });
762 self.tcx.sess.emit_err(errors::DocKeywordNotMod { span: meta.span() });
766 if !rustc_lexer::is_ident(doc_keyword.as_str()) {
767 self.tcx.sess.emit_err(errors::DocKeywordInvalidIdent {
768 span: meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
776 fn check_doc_fake_variadic(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
777 match self.tcx.hir().find(hir_id).and_then(|node| match node {
778 hir::Node::Item(item) => Some(&item.kind),
781 Some(ItemKind::Impl(ref i)) => {
782 let is_valid = matches!(&i.self_ty.kind, hir::TyKind::Tup([_]))
783 || if let hir::TyKind::BareFn(bare_fn_ty) = &i.self_ty.kind {
784 bare_fn_ty.decl.inputs.len() == 1
789 self.tcx.sess.emit_err(errors::DocFakeVariadicNotValid { span: meta.span() });
794 self.tcx.sess.emit_err(errors::DocKeywordOnlyImpl { span: meta.span() });
801 /// Checks `#[doc(inline)]`/`#[doc(no_inline)]` attributes. Returns `true` if valid.
803 /// A doc inlining attribute is invalid if it is applied to a non-`use` item, or
804 /// if there are conflicting attributes for one item.
806 /// `specified_inline` is used to keep track of whether we have
807 /// already seen an inlining attribute for this item.
808 /// If so, `specified_inline` holds the value and the span of
809 /// the first `inline`/`no_inline` attribute.
813 meta: &NestedMetaItem,
816 specified_inline: &mut Option<(bool, Span)>,
818 if target == Target::Use || target == Target::ExternCrate {
819 let do_inline = meta.name_or_empty() == sym::inline;
820 if let Some((prev_inline, prev_span)) = *specified_inline {
821 if do_inline != prev_inline {
822 let mut spans = MultiSpan::from_spans(vec![prev_span, meta.span()]);
823 spans.push_span_label(prev_span, fluent::passes::doc_inline_conflict_first);
824 spans.push_span_label(meta.span(), fluent::passes::doc_inline_conflict_second);
825 self.tcx.sess.emit_err(errors::DocKeywordConflict { spans });
830 *specified_inline = Some((do_inline, meta.span()));
834 self.tcx.emit_spanned_lint(
835 INVALID_DOC_ATTRIBUTES,
838 errors::DocInlineOnlyUse {
839 attr_span: meta.span(),
840 item_span: (attr.style == AttrStyle::Outer)
841 .then(|| self.tcx.hir().span(hir_id)),
848 /// Checks that an attribute is *not* used at the crate level. Returns `true` if valid.
849 fn check_attr_not_crate_level(
851 meta: &NestedMetaItem,
855 if CRATE_HIR_ID == hir_id {
856 self.tcx.sess.emit_err(errors::DocAttrNotCrateLevel { span: meta.span(), attr_name });
862 /// Checks that an attribute is used at the crate level. Returns `true` if valid.
863 fn check_attr_crate_level(
866 meta: &NestedMetaItem,
869 if hir_id != CRATE_HIR_ID {
870 self.tcx.struct_span_lint_hir(INVALID_DOC_ATTRIBUTES, hir_id, meta.span(), |lint| {
871 let mut err = lint.build(fluent::passes::attr_crate_level);
872 if attr.style == AttrStyle::Outer
873 && self.tcx.hir().get_parent_item(hir_id) == CRATE_DEF_ID
875 if let Ok(mut src) = self.tcx.sess.source_map().span_to_snippet(attr.span) {
877 err.span_suggestion_verbose(
879 fluent::passes::suggestion,
881 Applicability::MaybeIncorrect,
884 err.span_help(attr.span, fluent::passes::help);
887 err.note(fluent::passes::note).emit();
894 /// Checks that `doc(test(...))` attribute contains only valid attributes. Returns `true` if
896 fn check_test_attr(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
897 let mut is_valid = true;
898 if let Some(metas) = meta.meta_item_list() {
899 for i_meta in metas {
900 match i_meta.name_or_empty() {
901 sym::attr | sym::no_crate_inject => {}
903 self.tcx.emit_spanned_lint(
904 INVALID_DOC_ATTRIBUTES,
907 errors::DocTestUnknown {
908 path: rustc_ast_pretty::pprust::path_to_string(
909 &i_meta.meta_item().unwrap().path,
918 self.tcx.emit_spanned_lint(
919 INVALID_DOC_ATTRIBUTES,
922 errors::DocTestTakesList,
929 /// Runs various checks on `#[doc]` attributes. Returns `true` if valid.
931 /// `specified_inline` should be initialized to `None` and kept for the scope
932 /// of one item. Read the documentation of [`check_doc_inline`] for more information.
934 /// [`check_doc_inline`]: Self::check_doc_inline
940 specified_inline: &mut Option<(bool, Span)>,
941 aliases: &mut FxHashMap<String, Span>,
943 let mut is_valid = true;
945 if let Some(mi) = attr.meta() && let Some(list) = mi.meta_item_list() {
947 if let Some(i_meta) = meta.meta_item() {
948 match i_meta.name_or_empty() {
950 if !self.check_attr_not_crate_level(meta, hir_id, "alias")
951 || !self.check_doc_alias(meta, hir_id, target, aliases) =>
957 if !self.check_attr_not_crate_level(meta, hir_id, "keyword")
958 || !self.check_doc_keyword(meta, hir_id) =>
964 if !self.check_attr_not_crate_level(meta, hir_id, "fake_variadic")
965 || !self.check_doc_fake_variadic(meta, hir_id) =>
970 sym::html_favicon_url
972 | sym::html_playground_url
973 | sym::issue_tracker_base_url
975 | sym::html_no_source
977 if !self.check_attr_crate_level(attr, meta, hir_id) =>
982 sym::inline | sym::no_inline
983 if !self.check_doc_inline(
994 // no_default_passes: deprecated
995 // passes: deprecated
996 // plugins: removed, but rustdoc warns about it itself
1001 | sym::html_favicon_url
1002 | sym::html_logo_url
1003 | sym::html_no_source
1004 | sym::html_playground_url
1005 | sym::html_root_url
1007 | sym::issue_tracker_base_url
1010 | sym::no_default_passes
1012 | sym::notable_trait
1015 | sym::fake_variadic => {}
1018 if !self.check_test_attr(meta, hir_id) {
1024 if !self.tcx.features().rustdoc_internals {
1025 self.tcx.emit_spanned_lint(
1026 INVALID_DOC_ATTRIBUTES,
1029 errors::DocPrimitive,
1035 let path = rustc_ast_pretty::pprust::path_to_string(&i_meta.path);
1036 if i_meta.has_name(sym::spotlight) {
1037 self.tcx.emit_spanned_lint(
1038 INVALID_DOC_ATTRIBUTES,
1041 errors::DocTestUnknownSpotlight {
1046 } else if i_meta.has_name(sym::include) &&
1047 let Some(value) = i_meta.value_str() {
1048 let applicability = if list.len() == 1 {
1049 Applicability::MachineApplicable
1051 Applicability::MaybeIncorrect
1053 // If there are multiple attributes, the suggestion would suggest
1054 // deleting all of them, which is incorrect.
1055 self.tcx.emit_spanned_lint(
1056 INVALID_DOC_ATTRIBUTES,
1059 errors::DocTestUnknownInclude {
1061 value: value.to_string(),
1062 inner: (attr.style == AttrStyle::Inner)
1065 sugg: (attr.meta().unwrap().span, applicability),
1069 self.tcx.emit_spanned_lint(
1070 INVALID_DOC_ATTRIBUTES,
1073 errors::DocTestUnknownAny { path }
1080 self.tcx.emit_spanned_lint(
1081 INVALID_DOC_ATTRIBUTES,
1094 /// Warns against some misuses of `#[pass_by_value]`
1095 fn check_pass_by_value(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1097 Target::Struct | Target::Enum | Target::TyAlias => true,
1099 self.tcx.sess.emit_err(errors::PassByValue { attr_span: attr.span, span });
1105 fn check_allow_incoherent_impl(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1107 Target::Method(MethodKind::Inherent) => true,
1109 self.tcx.sess.emit_err(errors::AllowIncoherentImpl { attr_span: attr.span, span });
1115 fn check_has_incoherent_inherent_impls(
1122 Target::Trait | Target::Struct | Target::Enum | Target::Union | Target::ForeignTy => {
1128 .emit_err(errors::HasIncoherentInherentImpl { attr_span: attr.span, span });
1134 /// Warns against some misuses of `#[must_use]`
1135 fn check_must_use(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
1136 let node = self.tcx.hir().get(hir_id);
1137 if let Some(kind) = node.fn_kind() && let rustc_hir::IsAsync::Async = kind.asyncness() {
1138 self.tcx.emit_spanned_lint(
1142 errors::MustUseAsync { span }
1154 // `impl Trait` in return position can trip
1155 // `unused_must_use` if `Trait` is marked as
1159 let article = match target {
1164 | Target::Expression
1166 | Target::AssocConst
1167 | Target::AssocTy => "an",
1171 self.tcx.emit_spanned_lint(
1175 errors::MustUseNoEffect { article, target },
1179 // For now, its always valid
1183 /// Checks if `#[must_not_suspend]` is applied to a function. Returns `true` if valid.
1184 fn check_must_not_suspend(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1186 Target::Struct | Target::Enum | Target::Union | Target::Trait => true,
1188 self.tcx.sess.emit_err(errors::MustNotSuspend { attr_span: attr.span, span });
1194 /// Checks if `#[cold]` is applied to a non-function. Returns `true` if valid.
1195 fn check_cold(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1197 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => {}
1198 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1199 // `#[cold]` attribute with just a lint, because we previously
1200 // erroneously allowed it and some crates used it accidentally, to to be compatible
1201 // with crates depending on them, we can't throw an error here.
1202 Target::Field | Target::Arm | Target::MacroDef => {
1203 self.inline_attr_str_error_with_macro_def(hir_id, attr, "cold");
1206 // FIXME: #[cold] was previously allowed on non-functions and some crates used
1207 // this, so only emit a warning.
1208 self.tcx.emit_spanned_lint(
1212 errors::Cold { span },
1218 /// Checks if `#[link]` is applied to an item other than a foreign module.
1219 fn check_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1220 if target == Target::ForeignMod
1221 && let hir::Node::Item(item) = self.tcx.hir().get(hir_id)
1222 && let Item { kind: ItemKind::ForeignMod { abi, .. }, .. } = item
1223 && !matches!(abi, Abi::Rust | Abi::RustIntrinsic | Abi::PlatformIntrinsic)
1228 self.tcx.emit_spanned_lint(
1232 errors::Link { span: (target != Target::ForeignMod).then_some(span) },
1236 /// Checks if `#[link_name]` is applied to an item other than a foreign function or static.
1237 fn check_link_name(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1239 Target::ForeignFn | Target::ForeignStatic => {}
1240 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1241 // `#[link_name]` attribute with just a lint, because we previously
1242 // erroneously allowed it and some crates used it accidentally, to to be compatible
1243 // with crates depending on them, we can't throw an error here.
1244 Target::Field | Target::Arm | Target::MacroDef => {
1245 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_name");
1248 // FIXME: #[cold] was previously allowed on non-functions/statics and some crates
1249 // used this, so only emit a warning.
1250 let attr_span = matches!(target, Target::ForeignMod).then_some(attr.span);
1251 if let Some(s) = attr.value_str() {
1252 self.tcx.emit_spanned_lint(
1256 errors::LinkName { span, attr_span, value: s.as_str() },
1259 self.tcx.emit_spanned_lint(
1263 errors::LinkName { span, attr_span, value: "..." },
1270 /// Checks if `#[no_link]` is applied to an `extern crate`. Returns `true` if valid.
1271 fn check_no_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
1273 Target::ExternCrate => true,
1274 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1275 // `#[no_link]` attribute with just a lint, because we previously
1276 // erroneously allowed it and some crates used it accidentally, to 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, "no_link");
1283 self.tcx.sess.emit_err(errors::NoLink { attr_span: attr.span, span });
1289 fn is_impl_item(&self, hir_id: HirId) -> bool {
1290 matches!(self.tcx.hir().get(hir_id), hir::Node::ImplItem(..))
1293 /// Checks if `#[export_name]` is applied to a function or static. Returns `true` if valid.
1294 fn check_export_name(
1302 Target::Static | Target::Fn => true,
1303 Target::Method(..) if self.is_impl_item(hir_id) => true,
1304 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1305 // `#[export_name]` attribute with just a lint, because we previously
1306 // erroneously allowed it and some crates used it accidentally, to 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, "export_name");
1313 self.tcx.sess.emit_err(errors::ExportName { attr_span: attr.span, span });
1319 fn check_rustc_layout_scalar_valid_range(
1325 if target != Target::Struct {
1326 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeNotStruct {
1327 attr_span: attr.span,
1333 let Some(list) = attr.meta_item_list() else {
1337 if matches!(&list[..], &[NestedMetaItem::Literal(Lit { kind: LitKind::Int(..), .. })]) {
1340 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeArg { attr_span: attr.span });
1345 /// Checks if `#[rustc_legacy_const_generics]` is applied to a function and has a valid argument.
1346 fn check_rustc_legacy_const_generics(
1351 item: Option<ItemLike<'_>>,
1353 let is_function = matches!(target, Target::Fn);
1355 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1356 attr_span: attr.span,
1362 let Some(list) = attr.meta_item_list() else {
1363 // The attribute form is validated on AST.
1367 let Some(ItemLike::Item(Item {
1368 kind: ItemKind::Fn(FnSig { decl, .. }, generics, _),
1371 bug!("should be a function item");
1374 for param in generics.params {
1376 hir::GenericParamKind::Const { .. } => {}
1378 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsOnly {
1379 attr_span: attr.span,
1380 param_span: param.span,
1387 if list.len() != generics.params.len() {
1388 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndex {
1389 attr_span: attr.span,
1390 generics_span: generics.span,
1395 let arg_count = decl.inputs.len() as u128 + generics.params.len() as u128;
1396 let mut invalid_args = vec![];
1398 if let Some(LitKind::Int(val, _)) = meta.literal().map(|lit| &lit.kind) {
1399 if *val >= arg_count {
1400 let span = meta.span();
1401 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexExceed {
1403 arg_count: arg_count as usize,
1408 invalid_args.push(meta.span());
1412 if !invalid_args.is_empty() {
1413 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexNegative { invalid_args });
1420 /// Helper function for checking that the provided attribute is only applied to a function or
1422 fn check_applied_to_fn_or_method(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1423 let is_function = matches!(target, Target::Fn | Target::Method(..));
1425 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1426 attr_span: attr.span,
1435 /// Checks that the `#[rustc_lint_query_instability]` attribute is only applied to a function
1437 fn check_rustc_lint_query_instability(
1443 self.check_applied_to_fn_or_method(attr, span, target)
1446 /// Checks that the `#[rustc_lint_diagnostics]` attribute is only applied to a function or
1448 fn check_rustc_lint_diagnostics(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1449 self.check_applied_to_fn_or_method(attr, span, target)
1452 /// Checks that the `#[rustc_lint_opt_ty]` attribute is only applied to a struct.
1453 fn check_rustc_lint_opt_ty(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1455 Target::Struct => true,
1457 self.tcx.sess.emit_err(errors::RustcLintOptTy { attr_span: attr.span, span });
1463 /// Checks that the `#[rustc_lint_opt_deny_field_access]` attribute is only applied to a field.
1464 fn check_rustc_lint_opt_deny_field_access(
1471 Target::Field => true,
1475 .emit_err(errors::RustcLintOptDenyFieldAccess { attr_span: attr.span, span });
1481 /// Checks that the dep-graph debugging attributes are only present when the query-dep-graph
1482 /// option is passed to the compiler.
1483 fn check_rustc_dirty_clean(&self, attr: &Attribute) -> bool {
1484 if self.tcx.sess.opts.unstable_opts.query_dep_graph {
1487 self.tcx.sess.emit_err(errors::RustcDirtyClean { span: attr.span });
1492 /// Checks if `#[link_section]` is applied to a function or static.
1493 fn check_link_section(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1495 Target::Static | Target::Fn | Target::Method(..) => {}
1496 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1497 // `#[link_section]` attribute with just a lint, because we previously
1498 // erroneously allowed it and some crates used it accidentally, to to be compatible
1499 // with crates depending on them, we can't throw an error here.
1500 Target::Field | Target::Arm | Target::MacroDef => {
1501 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_section");
1504 // FIXME: #[link_section] was previously allowed on non-functions/statics and some
1505 // crates used this, so only emit a warning.
1506 self.tcx.emit_spanned_lint(
1510 errors::LinkSection { span },
1516 /// Checks if `#[no_mangle]` is applied to a function or static.
1517 fn check_no_mangle(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1519 Target::Static | Target::Fn => {}
1520 Target::Method(..) if self.is_impl_item(hir_id) => {}
1521 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1522 // `#[no_mangle]` attribute with just a lint, because we previously
1523 // erroneously allowed it and some crates used it accidentally, to to be compatible
1524 // with crates depending on them, we can't throw an error here.
1525 Target::Field | Target::Arm | Target::MacroDef => {
1526 self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_mangle");
1528 // FIXME: #[no_mangle] was previously allowed on non-functions/statics, this should be an error
1529 // The error should specify that the item that is wrong is specifically a *foreign* fn/static
1530 // otherwise the error seems odd
1531 Target::ForeignFn | Target::ForeignStatic => {
1532 let foreign_item_kind = match target {
1533 Target::ForeignFn => "function",
1534 Target::ForeignStatic => "static",
1535 _ => unreachable!(),
1537 self.tcx.emit_spanned_lint(
1541 errors::NoMangleForeign { span, attr_span: attr.span, foreign_item_kind },
1545 // FIXME: #[no_mangle] was previously allowed on non-functions/statics and some
1546 // crates used this, so only emit a warning.
1547 self.tcx.emit_spanned_lint(
1551 errors::NoMangle { span },
1557 /// Checks if the `#[repr]` attributes on `item` are valid.
1560 attrs: &[Attribute],
1563 item: Option<ItemLike<'_>>,
1566 // Extract the names of all repr hints, e.g., [foo, bar, align] for:
1569 // #[repr(bar, align(8))]
1571 let hints: Vec<_> = attrs
1573 .filter(|attr| attr.has_name(sym::repr))
1574 .filter_map(|attr| attr.meta_item_list())
1578 let mut int_reprs = 0;
1579 let mut is_c = false;
1580 let mut is_simd = false;
1581 let mut is_transparent = false;
1583 for hint in &hints {
1584 if !hint.is_meta_item() {
1585 self.tcx.sess.emit_err(errors::ReprIdent { span: hint.span() });
1589 let (article, allowed_targets) = match hint.name_or_empty() {
1593 Target::Struct | Target::Union | Target::Enum => continue,
1594 _ => ("a", "struct, enum, or union"),
1598 if let (Target::Fn, false) = (target, self.tcx.features().fn_align) {
1600 &self.tcx.sess.parse_sess,
1603 "`repr(align)` attributes on functions are unstable",
1609 Target::Struct | Target::Union | Target::Enum | Target::Fn => continue,
1610 _ => ("a", "struct, enum, function, or union"),
1614 if target != Target::Struct && target != Target::Union {
1615 ("a", "struct or union")
1622 if target != Target::Struct {
1628 sym::transparent => {
1629 is_transparent = true;
1631 Target::Struct | Target::Union | Target::Enum => continue,
1632 _ => ("a", "struct, enum, or union"),
1648 if target != Target::Enum {
1659 "unrecognized representation hint"
1672 &format!("attribute should be applied to {article} {allowed_targets}")
1674 .span_label(span, &format!("not {article} {allowed_targets}"))
1678 // Just point at all repr hints if there are any incompatibilities.
1679 // This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
1680 let hint_spans = hints.iter().map(|hint| hint.span());
1682 // Error on repr(transparent, <anything else>).
1683 if is_transparent && hints.len() > 1 {
1684 let hint_spans: Vec<_> = hint_spans.clone().collect();
1689 "transparent {} cannot have other repr hints",
1694 // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
1696 || (is_simd && is_c)
1699 && item.map_or(false, |item| {
1700 if let ItemLike::Item(item) = item {
1701 return is_c_like_enum(item);
1706 self.tcx.emit_spanned_lint(
1707 CONFLICTING_REPR_HINTS,
1709 hint_spans.collect::<Vec<Span>>(),
1710 errors::ReprConflicting,
1715 fn check_used(&self, attrs: &[Attribute], target: Target) {
1716 let mut used_linker_span = None;
1717 let mut used_compiler_span = None;
1718 for attr in attrs.iter().filter(|attr| attr.has_name(sym::used)) {
1719 if target != Target::Static {
1720 self.tcx.sess.emit_err(errors::UsedStatic { span: attr.span });
1722 let inner = attr.meta_item_list();
1723 match inner.as_deref() {
1724 Some([item]) if item.has_name(sym::linker) => {
1725 if used_linker_span.is_none() {
1726 used_linker_span = Some(attr.span);
1729 Some([item]) if item.has_name(sym::compiler) => {
1730 if used_compiler_span.is_none() {
1731 used_compiler_span = Some(attr.span);
1735 // This error case is handled in rustc_typeck::collect.
1738 // Default case (compiler) when arg isn't defined.
1739 if used_compiler_span.is_none() {
1740 used_compiler_span = Some(attr.span);
1745 if let (Some(linker_span), Some(compiler_span)) = (used_linker_span, used_compiler_span) {
1748 .emit_err(errors::UsedCompilerLinker { spans: vec![linker_span, compiler_span] });
1752 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1753 /// (Allows proc_macro functions)
1754 fn check_allow_internal_unstable(
1760 attrs: &[Attribute],
1762 debug!("Checking target: {:?}", target);
1766 if self.tcx.sess.is_proc_macro_attr(attr) {
1767 debug!("Is proc macro attr");
1771 debug!("Is not proc macro attr");
1774 Target::MacroDef => true,
1775 // FIXME(#80564): We permit struct fields and match arms to have an
1776 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1777 // erroneously allowed it and some crates used it accidentally, to to be compatible
1778 // with crates depending on them, we can't throw an error here.
1779 Target::Field | Target::Arm => {
1780 self.inline_attr_str_error_without_macro_def(
1783 "allow_internal_unstable",
1790 .emit_err(errors::AllowInternalUnstable { attr_span: attr.span, span });
1796 /// Checks if the items on the `#[debugger_visualizer]` attribute are valid.
1797 fn check_debugger_visualizer(&self, attr: &Attribute, target: Target) -> bool {
1801 self.tcx.sess.emit_err(errors::DebugVisualizerPlacement { span: attr.span });
1806 let Some(hints) = attr.meta_item_list() else {
1807 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1811 let hint = match hints.len() {
1814 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1819 let Some(meta_item) = hint.meta_item() else {
1820 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1824 let visualizer_path = match (meta_item.name_or_empty(), meta_item.value_str()) {
1825 (sym::natvis_file, Some(value)) => value,
1826 (sym::gdb_script_file, Some(value)) => value,
1828 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: meta_item.span });
1834 match resolve_path(&self.tcx.sess.parse_sess, visualizer_path.as_str(), attr.span) {
1842 match std::fs::File::open(&file) {
1849 &format!("couldn't read {}: {}", file.display(), err),
1857 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1858 /// (Allows proc_macro functions)
1859 fn check_rustc_allow_const_fn_unstable(
1867 Target::Fn | Target::Method(_)
1868 if self.tcx.is_const_fn_raw(self.tcx.hir().local_def_id(hir_id).to_def_id()) =>
1872 // FIXME(#80564): We permit struct fields and match arms to have an
1873 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1874 // erroneously allowed it and some crates used it accidentally, to to be compatible
1875 // with crates depending on them, we can't throw an error here.
1876 Target::Field | Target::Arm | Target::MacroDef => {
1877 self.inline_attr_str_error_with_macro_def(hir_id, attr, "allow_internal_unstable");
1883 .emit_err(errors::RustcAllowConstFnUnstable { attr_span: attr.span, span });
1889 fn check_rustc_std_internal_symbol(
1896 Target::Fn | Target::Static => true,
1900 .emit_err(errors::RustcStdInternalSymbol { attr_span: attr.span, span });
1906 /// `#[const_trait]` only applies to traits.
1907 fn check_const_trait(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1909 Target::Trait => true,
1911 self.tcx.sess.emit_err(errors::ConstTrait { attr_span: attr.span });
1917 fn check_stability_promotable(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1919 Target::Expression => {
1920 self.tcx.sess.emit_err(errors::StabilityPromotable { attr_span: attr.span });
1927 fn check_link_ordinal(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1929 Target::ForeignFn | Target::ForeignStatic => true,
1931 self.tcx.sess.emit_err(errors::LinkOrdinal { attr_span: attr.span });
1937 fn check_deprecated(&self, hir_id: HirId, attr: &Attribute, _span: Span, target: Target) {
1939 Target::Closure | Target::Expression | Target::Statement | Target::Arm => {
1940 self.tcx.emit_spanned_lint(
1951 fn check_macro_use(&self, hir_id: HirId, attr: &Attribute, target: Target) {
1952 let name = attr.name_or_empty();
1954 Target::ExternCrate | Target::Mod => {}
1956 self.tcx.emit_spanned_lint(
1960 errors::MacroUse { name },
1966 fn check_macro_export(&self, hir_id: HirId, attr: &Attribute, target: Target) {
1967 if target != Target::MacroDef {
1968 self.tcx.emit_spanned_lint(UNUSED_ATTRIBUTES, hir_id, attr.span, errors::MacroExport);
1972 fn check_plugin_registrar(&self, hir_id: HirId, attr: &Attribute, target: Target) {
1973 if target != Target::Fn {
1974 self.tcx.emit_spanned_lint(
1978 errors::PluginRegistrar,
1983 fn check_unused_attribute(&self, hir_id: HirId, attr: &Attribute) {
1984 // Warn on useless empty attributes.
1985 let note = if matches!(
1986 attr.name_or_empty(),
1995 | sym::target_feature
1996 ) && attr.meta_item_list().map_or(false, |list| list.is_empty())
1998 errors::UnusedNote::EmptyList { name: attr.name_or_empty() }
2000 attr.name_or_empty(),
2001 sym::allow | sym::warn | sym::deny | sym::forbid | sym::expect
2002 ) && let Some(meta) = attr.meta_item_list()
2004 && let Some(item) = meta[0].meta_item()
2005 && let MetaItemKind::NameValue(_) = &item.kind
2006 && item.path == sym::reason
2008 errors::UnusedNote::NoLints { name: attr.name_or_empty() }
2009 } else if attr.name_or_empty() == sym::default_method_body_is_const {
2010 errors::UnusedNote::DefaultMethodBodyConst
2015 self.tcx.emit_spanned_lint(
2019 errors::Unused { attr_span: attr.span, note },
2024 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {
2025 type NestedFilter = nested_filter::OnlyBodies;
2027 fn nested_visit_map(&mut self) -> Self::Map {
2031 fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
2032 // Historically we've run more checks on non-exported than exported macros,
2033 // so this lets us continue to run them while maintaining backwards compatibility.
2034 // In the long run, the checks should be harmonized.
2035 if let ItemKind::Macro(ref macro_def, _) = item.kind {
2036 let def_id = item.def_id.to_def_id();
2037 if macro_def.macro_rules && !self.tcx.has_attr(def_id, sym::macro_export) {
2038 check_non_exported_macro_for_invalid_attrs(self.tcx, item);
2042 let target = Target::from_item(item);
2043 self.check_attributes(item.hir_id(), item.span, target, Some(ItemLike::Item(item)));
2044 intravisit::walk_item(self, item)
2047 fn visit_generic_param(&mut self, generic_param: &'tcx hir::GenericParam<'tcx>) {
2048 let target = Target::from_generic_param(generic_param);
2049 self.check_attributes(generic_param.hir_id, generic_param.span, target, None);
2050 intravisit::walk_generic_param(self, generic_param)
2053 fn visit_trait_item(&mut self, trait_item: &'tcx TraitItem<'tcx>) {
2054 let target = Target::from_trait_item(trait_item);
2055 self.check_attributes(trait_item.hir_id(), trait_item.span, target, None);
2056 intravisit::walk_trait_item(self, trait_item)
2059 fn visit_field_def(&mut self, struct_field: &'tcx hir::FieldDef<'tcx>) {
2060 self.check_attributes(struct_field.hir_id, struct_field.span, Target::Field, None);
2061 intravisit::walk_field_def(self, struct_field);
2064 fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
2065 self.check_attributes(arm.hir_id, arm.span, Target::Arm, None);
2066 intravisit::walk_arm(self, arm);
2069 fn visit_foreign_item(&mut self, f_item: &'tcx ForeignItem<'tcx>) {
2070 let target = Target::from_foreign_item(f_item);
2071 self.check_attributes(f_item.hir_id(), f_item.span, target, Some(ItemLike::ForeignItem));
2072 intravisit::walk_foreign_item(self, f_item)
2075 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
2076 let target = target_from_impl_item(self.tcx, impl_item);
2077 self.check_attributes(impl_item.hir_id(), impl_item.span, target, None);
2078 intravisit::walk_impl_item(self, impl_item)
2081 fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt<'tcx>) {
2082 // When checking statements ignore expressions, they will be checked later.
2083 if let hir::StmtKind::Local(ref l) = stmt.kind {
2084 self.check_attributes(l.hir_id, stmt.span, Target::Statement, None);
2086 intravisit::walk_stmt(self, stmt)
2089 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
2090 let target = match expr.kind {
2091 hir::ExprKind::Closure { .. } => Target::Closure,
2092 _ => Target::Expression,
2095 self.check_attributes(expr.hir_id, expr.span, target, None);
2096 intravisit::walk_expr(self, expr)
2099 fn visit_expr_field(&mut self, field: &'tcx hir::ExprField<'tcx>) {
2100 self.check_attributes(field.hir_id, field.span, Target::ExprField, None);
2101 intravisit::walk_expr_field(self, field)
2104 fn visit_variant(&mut self, variant: &'tcx hir::Variant<'tcx>) {
2105 self.check_attributes(variant.id, variant.span, Target::Variant, None);
2106 intravisit::walk_variant(self, variant)
2109 fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {
2110 self.check_attributes(param.hir_id, param.span, Target::Param, None);
2112 intravisit::walk_param(self, param);
2115 fn visit_pat_field(&mut self, field: &'tcx hir::PatField<'tcx>) {
2116 self.check_attributes(field.hir_id, field.span, Target::PatField, None);
2117 intravisit::walk_pat_field(self, field);
2121 fn is_c_like_enum(item: &Item<'_>) -> bool {
2122 if let ItemKind::Enum(ref def, _) = item.kind {
2123 for variant in def.variants {
2124 match variant.data {
2125 hir::VariantData::Unit(..) => { /* continue */ }
2135 // FIXME: Fix "Cannot determine resolution" error and remove built-in macros
2137 fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
2138 // Check for builtin attributes at the crate level
2139 // which were unsuccessfully resolved due to cannot determine
2140 // resolution for the attribute macro error.
2141 const ATTRS_TO_CHECK: &[Symbol] = &[
2145 sym::automatically_derived,
2151 sym::global_allocator,
2156 // This function should only be called with crate attributes
2157 // which are inner attributes always but lets check to make sure
2158 if attr.style == AttrStyle::Inner {
2159 for attr_to_check in ATTRS_TO_CHECK {
2160 if attr.has_name(*attr_to_check) {
2161 let mut err = tcx.sess.struct_span_err(
2164 "`{}` attribute cannot be used at crate level",
2165 attr_to_check.to_ident_string()
2168 // Only emit an error with a suggestion if we can create a
2169 // string out of the attribute span
2170 if let Ok(src) = tcx.sess.source_map().span_to_snippet(attr.span) {
2171 let replacement = src.replace("#!", "#");
2172 err.span_suggestion_verbose(
2174 "perhaps you meant to use an outer attribute",
2176 rustc_errors::Applicability::MachineApplicable,
2186 fn check_non_exported_macro_for_invalid_attrs(tcx: TyCtxt<'_>, item: &Item<'_>) {
2187 let attrs = tcx.hir().attrs(item.hir_id());
2190 if attr.has_name(sym::inline) {
2191 tcx.sess.emit_err(errors::NonExportedMacroInvalidAttrs { attr_span: attr.span });
2196 fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
2197 let check_attr_visitor = &mut CheckAttrVisitor { tcx };
2198 tcx.hir().visit_item_likes_in_module(module_def_id, check_attr_visitor);
2199 if module_def_id.is_top_level_module() {
2200 check_attr_visitor.check_attributes(CRATE_HIR_ID, DUMMY_SP, Target::Mod, None);
2201 check_invalid_crate_level_attr(tcx, tcx.hir().krate_attrs());
2205 pub(crate) fn provide(providers: &mut Providers) {
2206 *providers = Providers { check_mod_attrs, ..*providers };
2209 fn check_duplicates(
2213 duplicates: AttributeDuplicates,
2214 seen: &mut FxHashMap<Symbol, Span>,
2216 use AttributeDuplicates::*;
2217 if matches!(duplicates, WarnFollowingWordOnly) && !attr.is_word() {
2222 WarnFollowing | FutureWarnFollowing | WarnFollowingWordOnly | FutureWarnPreceding => {
2223 match seen.entry(attr.name_or_empty()) {
2224 Entry::Occupied(mut entry) => {
2225 let (this, other) = if matches!(duplicates, FutureWarnPreceding) {
2226 let to_remove = entry.insert(attr.span);
2227 (to_remove, attr.span)
2229 (attr.span, *entry.get())
2231 tcx.emit_spanned_lint(
2235 errors::UnusedDuplicate {
2240 FutureWarnFollowing | FutureWarnPreceding
2246 Entry::Vacant(entry) => {
2247 entry.insert(attr.span);
2251 ErrorFollowing | ErrorPreceding => match seen.entry(attr.name_or_empty()) {
2252 Entry::Occupied(mut entry) => {
2253 let (this, other) = if matches!(duplicates, ErrorPreceding) {
2254 let to_remove = entry.insert(attr.span);
2255 (to_remove, attr.span)
2257 (attr.span, *entry.get())
2259 tcx.sess.emit_err(errors::UnusedMultiple {
2262 name: attr.name_or_empty(),
2265 Entry::Vacant(entry) => {
2266 entry.insert(attr.span);