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, ProcMacroDiffArguments, ProcMacroInvalidAbi, ProcMacroMissingArguments,
10 ProcMacroTypeError, ProcMacroUnsafe, TransparentIncompatible, UnrecognizedReprHint,
12 use rustc_ast::{ast, AttrStyle, Attribute, LitKind, MetaItemKind, MetaItemLit, NestedMetaItem};
13 use rustc_data_structures::fx::FxHashMap;
14 use rustc_errors::{fluent, Applicability, IntoDiagnosticArg, MultiSpan};
15 use rustc_expand::base::resolve_path;
16 use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
18 use rustc_hir::def_id::LocalDefId;
19 use rustc_hir::intravisit::{self, Visitor};
21 self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID, CRATE_OWNER_ID,
23 use rustc_hir::{MethodKind, Target, Unsafety};
24 use rustc_middle::hir::nested_filter;
25 use rustc_middle::middle::resolve_lifetime::ObjectLifetimeDefault;
26 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
27 use rustc_middle::ty::query::Providers;
28 use rustc_middle::ty::{ParamEnv, TyCtxt};
29 use rustc_session::lint::builtin::{
30 CONFLICTING_REPR_HINTS, INVALID_DOC_ATTRIBUTES, UNUSED_ATTRIBUTES,
32 use rustc_session::parse::feature_err;
33 use rustc_span::symbol::{kw, sym, Symbol};
34 use rustc_span::{Span, DUMMY_SP};
35 use rustc_target::spec::abi::Abi;
37 use std::collections::hash_map::Entry;
39 pub(crate) fn target_from_impl_item<'tcx>(
41 impl_item: &hir::ImplItem<'_>,
43 match impl_item.kind {
44 hir::ImplItemKind::Const(..) => Target::AssocConst,
45 hir::ImplItemKind::Fn(..) => {
46 let parent_def_id = tcx.hir().get_parent_item(impl_item.hir_id()).def_id;
47 let containing_item = tcx.hir().expect_item(parent_def_id);
48 let containing_impl_is_for_trait = match &containing_item.kind {
49 hir::ItemKind::Impl(impl_) => impl_.of_trait.is_some(),
50 _ => bug!("parent of an ImplItem must be an Impl"),
52 if containing_impl_is_for_trait {
53 Target::Method(MethodKind::Trait { body: true })
55 Target::Method(MethodKind::Inherent)
58 hir::ImplItemKind::Type(..) => Target::AssocTy,
62 #[derive(Clone, Copy)]
64 Item(&'tcx Item<'tcx>),
68 #[derive(Copy, Clone)]
69 pub(crate) enum ProcMacroKind {
75 impl IntoDiagnosticArg for ProcMacroKind {
76 fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
78 ProcMacroKind::Attribute => "attribute proc macro",
79 ProcMacroKind::Derive => "derive proc macro",
80 ProcMacroKind::FunctionLike => "function-like proc macro",
82 .into_diagnostic_arg()
86 struct CheckAttrVisitor<'tcx> {
89 // Whether or not this visitor should abort after finding errors
93 impl CheckAttrVisitor<'_> {
94 /// Checks any attribute.
100 item: Option<ItemLike<'_>>,
102 let mut doc_aliases = FxHashMap::default();
103 let mut is_valid = true;
104 let mut specified_inline = None;
105 let mut seen = FxHashMap::default();
106 let attrs = self.tcx.hir().attrs(hir_id);
108 let attr_is_valid = match attr.name_or_empty() {
109 sym::do_not_recommend => self.check_do_not_recommend(attr.span, target),
110 sym::inline => self.check_inline(hir_id, attr, span, target),
111 sym::no_coverage => self.check_no_coverage(hir_id, attr, span, target),
112 sym::non_exhaustive => self.check_non_exhaustive(hir_id, attr, span, target),
113 sym::marker => self.check_marker(hir_id, attr, span, target),
114 sym::rustc_must_implement_one_of => {
115 self.check_rustc_must_implement_one_of(attr, span, target)
117 sym::target_feature => self.check_target_feature(hir_id, attr, span, target),
118 sym::thread_local => self.check_thread_local(attr, span, target),
119 sym::track_caller => {
120 self.check_track_caller(hir_id, attr.span, attrs, span, target)
122 sym::doc => self.check_doc_attrs(
126 &mut specified_inline,
129 sym::no_link => self.check_no_link(hir_id, &attr, span, target),
130 sym::export_name => self.check_export_name(hir_id, &attr, span, target),
131 sym::rustc_layout_scalar_valid_range_start
132 | sym::rustc_layout_scalar_valid_range_end => {
133 self.check_rustc_layout_scalar_valid_range(&attr, span, target)
135 sym::allow_internal_unstable => {
136 self.check_allow_internal_unstable(hir_id, &attr, span, target, &attrs)
138 sym::debugger_visualizer => self.check_debugger_visualizer(&attr, target),
139 sym::rustc_allow_const_fn_unstable => {
140 self.check_rustc_allow_const_fn_unstable(hir_id, &attr, span, target)
142 sym::rustc_std_internal_symbol => {
143 self.check_rustc_std_internal_symbol(&attr, span, target)
145 sym::naked => self.check_naked(hir_id, attr, span, target),
146 sym::rustc_legacy_const_generics => {
147 self.check_rustc_legacy_const_generics(hir_id, &attr, span, target, item)
149 sym::rustc_lint_query_instability => {
150 self.check_rustc_lint_query_instability(hir_id, &attr, span, target)
152 sym::rustc_lint_diagnostics => {
153 self.check_rustc_lint_diagnostics(hir_id, &attr, span, target)
155 sym::rustc_lint_opt_ty => self.check_rustc_lint_opt_ty(&attr, span, target),
156 sym::rustc_lint_opt_deny_field_access => {
157 self.check_rustc_lint_opt_deny_field_access(&attr, span, target)
161 | sym::rustc_if_this_changed
162 | sym::rustc_then_this_would_need => self.check_rustc_dirty_clean(&attr),
163 sym::cmse_nonsecure_entry => {
164 self.check_cmse_nonsecure_entry(hir_id, attr, span, target)
166 sym::collapse_debuginfo => self.check_collapse_debuginfo(attr, span, target),
167 sym::const_trait => self.check_const_trait(attr, span, target),
168 sym::must_not_suspend => self.check_must_not_suspend(&attr, span, target),
169 sym::must_use => self.check_must_use(hir_id, &attr, target),
170 sym::rustc_pass_by_value => self.check_pass_by_value(&attr, span, target),
171 sym::rustc_allow_incoherent_impl => {
172 self.check_allow_incoherent_impl(&attr, span, target)
174 sym::rustc_has_incoherent_inherent_impls => {
175 self.check_has_incoherent_inherent_impls(&attr, span, target)
177 sym::rustc_const_unstable
178 | sym::rustc_const_stable
181 | sym::rustc_allowed_through_unstable_modules
182 | sym::rustc_promotable => self.check_stability_promotable(&attr, span, target),
183 sym::link_ordinal => self.check_link_ordinal(&attr, span, target),
186 is_valid &= attr_is_valid;
189 match attr.name_or_empty() {
190 sym::cold => self.check_cold(hir_id, attr, span, target),
191 sym::link => self.check_link(hir_id, attr, span, target),
192 sym::link_name => self.check_link_name(hir_id, attr, span, target),
193 sym::link_section => self.check_link_section(hir_id, attr, span, target),
194 sym::no_mangle => self.check_no_mangle(hir_id, attr, span, target),
195 sym::deprecated => self.check_deprecated(hir_id, attr, span, target),
196 sym::macro_use | sym::macro_escape => self.check_macro_use(hir_id, attr, target),
197 sym::path => self.check_generic_attr(hir_id, attr, target, Target::Mod),
198 sym::plugin_registrar => self.check_plugin_registrar(hir_id, attr, target),
199 sym::macro_export => self.check_macro_export(hir_id, attr, target),
200 sym::ignore | sym::should_panic => {
201 self.check_generic_attr(hir_id, attr, target, Target::Fn)
203 sym::automatically_derived => {
204 self.check_generic_attr(hir_id, attr, target, Target::Impl)
206 sym::no_implicit_prelude => {
207 self.check_generic_attr(hir_id, attr, target, Target::Mod)
209 sym::rustc_object_lifetime_default => self.check_object_lifetime_default(hir_id),
211 self.check_proc_macro(hir_id, target, ProcMacroKind::FunctionLike)
213 sym::proc_macro_attribute => {
214 self.check_proc_macro(hir_id, target, ProcMacroKind::Attribute);
216 sym::proc_macro_derive => {
217 self.check_generic_attr(hir_id, attr, target, Target::Fn);
218 self.check_proc_macro(hir_id, target, ProcMacroKind::Derive)
223 let builtin = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
225 if hir_id != CRATE_HIR_ID {
226 if let Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) =
227 attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name))
230 ast::AttrStyle::Outer => self.tcx.emit_spanned_lint(
234 errors::OuterCrateLevelAttr,
236 ast::AttrStyle::Inner => self.tcx.emit_spanned_lint(
240 errors::InnerCrateLevelAttr,
246 if let Some(BuiltinAttribute { duplicates, .. }) = builtin {
247 check_duplicates(self.tcx, attr, hir_id, *duplicates, &mut seen);
250 self.check_unused_attribute(hir_id, attr)
257 self.check_repr(attrs, span, target, item, hir_id);
258 self.check_used(attrs, target);
261 fn inline_attr_str_error_with_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
262 self.tcx.emit_spanned_lint(
266 errors::IgnoredAttrWithMacro { sym },
270 fn inline_attr_str_error_without_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
271 self.tcx.emit_spanned_lint(
275 errors::IgnoredAttr { sym },
279 /// Checks if `#[do_not_recommend]` is applied on a trait impl.
280 fn check_do_not_recommend(&self, attr_span: Span, target: Target) -> bool {
281 if let Target::Impl = target {
284 self.tcx.sess.emit_err(errors::IncorrectDoNotRecommendLocation { span: attr_span });
289 /// Checks if an `#[inline]` is applied to a function or a closure. Returns `true` if valid.
290 fn check_inline(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
294 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
295 Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
296 self.tcx.emit_spanned_lint(
300 errors::IgnoredInlineAttrFnProto,
304 // FIXME(#65833): We permit associated consts to have an `#[inline]` attribute with
305 // just a lint, because we previously erroneously allowed it and some crates used it
306 // accidentally, to be compatible with crates depending on them, we can't throw an
308 Target::AssocConst => {
309 self.tcx.emit_spanned_lint(
313 errors::IgnoredInlineAttrConstants,
317 // FIXME(#80564): Same for fields, arms, and macro defs
318 Target::Field | Target::Arm | Target::MacroDef => {
319 self.inline_attr_str_error_with_macro_def(hir_id, attr, "inline");
323 self.tcx.sess.emit_err(errors::InlineNotFnOrClosure {
324 attr_span: attr.span,
332 /// Checks if a `#[no_coverage]` is applied directly to a function
333 fn check_no_coverage(
341 // no_coverage on function is fine
344 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
346 // function prototypes can't be covered
347 Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
348 self.tcx.emit_spanned_lint(
352 errors::IgnoredNoCoverageFnProto,
357 Target::Mod | Target::ForeignMod | Target::Impl | Target::Trait => {
358 self.tcx.emit_spanned_lint(
362 errors::IgnoredNoCoveragePropagate,
367 Target::Expression | Target::Statement | Target::Arm => {
368 self.tcx.emit_spanned_lint(
372 errors::IgnoredNoCoverageFnDefn,
378 self.tcx.sess.emit_err(errors::IgnoredNoCoverageNotCoverable {
379 attr_span: attr.span,
387 fn check_generic_attr(
392 allowed_target: Target,
394 if target != allowed_target {
395 self.tcx.emit_spanned_lint(
400 attr_name: attr.name_or_empty(),
401 target_name: allowed_target.name().replace(' ', "_"),
407 /// Checks if `#[naked]` is applied to a function definition.
408 fn check_naked(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
411 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
412 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
413 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
414 // erroneously allowed it and some crates used it accidentally, to be compatible
415 // with crates depending on them, we can't throw an error here.
416 Target::Field | Target::Arm | Target::MacroDef => {
417 self.inline_attr_str_error_with_macro_def(hir_id, attr, "naked");
421 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
422 attr_span: attr.span,
424 on_crate: hir_id == CRATE_HIR_ID,
431 /// Checks if `#[cmse_nonsecure_entry]` is applied to a function definition.
432 fn check_cmse_nonsecure_entry(
441 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
443 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
444 attr_span: attr.span,
446 on_crate: hir_id == CRATE_HIR_ID,
453 /// Debugging aid for `object_lifetime_default` query.
454 fn check_object_lifetime_default(&self, hir_id: HirId) {
456 if let Some(generics) = tcx.hir().get_generics(tcx.hir().local_def_id(hir_id)) {
457 for p in generics.params {
458 let hir::GenericParamKind::Type { .. } = p.kind else { continue };
459 let default = tcx.object_lifetime_default(p.def_id);
460 let repr = match default {
461 ObjectLifetimeDefault::Empty => "BaseDefault".to_owned(),
462 ObjectLifetimeDefault::Static => "'static".to_owned(),
463 ObjectLifetimeDefault::Param(def_id) => tcx.item_name(def_id).to_string(),
464 ObjectLifetimeDefault::Ambiguous => "Ambiguous".to_owned(),
466 tcx.sess.emit_err(ObjectLifetimeErr { span: p.span, repr });
471 /// Checks if `#[collapse_debuginfo]` is applied to a macro.
472 fn check_collapse_debuginfo(&self, attr: &Attribute, span: Span, target: Target) -> bool {
474 Target::MacroDef => true,
478 .emit_err(errors::CollapseDebuginfo { attr_span: attr.span, defn_span: span });
484 /// Checks if a `#[track_caller]` is applied to a non-naked function. Returns `true` if valid.
485 fn check_track_caller(
494 _ if attrs.iter().any(|attr| attr.has_name(sym::naked)) => {
495 self.tcx.sess.emit_err(errors::NakedTrackedCaller { attr_span });
498 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => true,
499 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
500 // `#[track_caller]` attribute with just a lint, because we previously
501 // erroneously allowed it and some crates used it accidentally, to be compatible
502 // with crates depending on them, we can't throw an error here.
503 Target::Field | Target::Arm | Target::MacroDef => {
505 self.inline_attr_str_error_with_macro_def(hir_id, attr, "track_caller");
510 self.tcx.sess.emit_err(errors::TrackedCallerWrongLocation {
513 on_crate: hir_id == CRATE_HIR_ID,
520 /// Checks if the `#[non_exhaustive]` attribute on an `item` is valid. Returns `true` if valid.
521 fn check_non_exhaustive(
529 Target::Struct | Target::Enum | Target::Variant => true,
530 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
531 // `#[non_exhaustive]` attribute with just a lint, because we previously
532 // erroneously allowed it and some crates used it accidentally, to be compatible
533 // with crates depending on them, we can't throw an error here.
534 Target::Field | Target::Arm | Target::MacroDef => {
535 self.inline_attr_str_error_with_macro_def(hir_id, attr, "non_exhaustive");
539 self.tcx.sess.emit_err(errors::NonExhaustiveWrongLocation {
540 attr_span: attr.span,
548 /// Checks if the `#[marker]` attribute on an `item` is valid. Returns `true` if valid.
549 fn check_marker(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
551 Target::Trait => true,
552 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
553 // `#[marker]` attribute with just a lint, because we previously
554 // erroneously allowed it and some crates used it accidentally, to be compatible
555 // with crates depending on them, we can't throw an error here.
556 Target::Field | Target::Arm | Target::MacroDef => {
557 self.inline_attr_str_error_with_macro_def(hir_id, attr, "marker");
561 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
562 attr_span: attr.span,
570 /// Checks if the `#[rustc_must_implement_one_of]` attribute on a `target` is valid. Returns `true` if valid.
571 fn check_rustc_must_implement_one_of(
578 Target::Trait => true,
580 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
581 attr_span: attr.span,
589 /// Checks if the `#[target_feature]` attribute on `item` is valid. Returns `true` if valid.
590 fn check_target_feature(
599 | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
600 // FIXME: #[target_feature] was previously erroneously allowed on statements and some
601 // crates used this, so only emit a warning.
602 Target::Statement => {
603 self.tcx.emit_spanned_lint(
607 errors::TargetFeatureOnStatement,
611 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
612 // `#[target_feature]` attribute with just a lint, because we previously
613 // erroneously allowed it and some crates used it accidentally, to be compatible
614 // with crates depending on them, we can't throw an error here.
615 Target::Field | Target::Arm | Target::MacroDef => {
616 self.inline_attr_str_error_with_macro_def(hir_id, attr, "target_feature");
620 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
621 attr_span: attr.span,
623 on_crate: hir_id == CRATE_HIR_ID,
630 /// Checks if the `#[thread_local]` attribute on `item` is valid. Returns `true` if valid.
631 fn check_thread_local(&self, attr: &Attribute, span: Span, target: Target) -> bool {
633 Target::ForeignStatic | Target::Static => true,
635 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToStatic {
636 attr_span: attr.span,
644 fn doc_attr_str_error(&self, meta: &NestedMetaItem, attr_name: &str) {
645 self.tcx.sess.emit_err(errors::DocExpectStr { attr_span: meta.span(), attr_name });
648 fn check_doc_alias_value(
650 meta: &NestedMetaItem,
655 aliases: &mut FxHashMap<String, Span>,
658 let span = meta.name_value_literal_span().unwrap_or_else(|| meta.span());
660 &format!("`#[doc(alias{})]`", if is_list { "(\"...\")" } else { " = \"...\"" });
661 if doc_alias == kw::Empty {
662 tcx.sess.emit_err(errors::DocAliasEmpty { span, attr_str });
666 let doc_alias_str = doc_alias.as_str();
667 if let Some(c) = doc_alias_str
669 .find(|&c| c == '"' || c == '\'' || (c.is_whitespace() && c != ' '))
671 tcx.sess.emit_err(errors::DocAliasBadChar { span, attr_str, char_: c });
674 if doc_alias_str.starts_with(' ') || doc_alias_str.ends_with(' ') {
675 tcx.sess.emit_err(errors::DocAliasStartEnd { span, attr_str });
679 let span = meta.span();
680 if let Some(location) = match target {
682 let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
683 let containing_item = self.tcx.hir().expect_item(parent_def_id);
684 if Target::from_item(containing_item) == Target::Impl {
685 Some("type alias in implementation block")
690 Target::AssocConst => {
691 let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
692 let containing_item = self.tcx.hir().expect_item(parent_def_id);
693 // We can't link to trait impl's consts.
694 let err = "associated constant in trait implementation block";
695 match containing_item.kind {
696 ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => Some(err),
700 // we check the validity of params elsewhere
701 Target::Param => return false,
707 | Target::Impl => Some(target.name()),
717 | Target::ImplTraitPlaceholder
727 | Target::ForeignStatic
729 | Target::GenericParam(..)
732 | Target::ExprField => None,
734 tcx.sess.emit_err(errors::DocAliasBadLocation { span, attr_str, location });
737 let item_name = self.tcx.hir().name(hir_id);
738 if item_name == doc_alias {
739 tcx.sess.emit_err(errors::DocAliasNotAnAlias { span, attr_str });
742 if let Err(entry) = aliases.try_insert(doc_alias_str.to_owned(), span) {
743 self.tcx.emit_spanned_lint(
747 errors::DocAliasDuplicated { first_defn: *entry.entry.get() },
755 meta: &NestedMetaItem,
758 aliases: &mut FxHashMap<String, Span>,
760 if let Some(values) = meta.meta_item_list() {
764 Some(l) => match l.kind {
765 LitKind::Str(s, _) => {
766 if !self.check_doc_alias_value(v, s, hir_id, target, true, aliases) {
773 .emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
778 self.tcx.sess.emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
784 } else if let Some(doc_alias) = meta.value_str() {
785 self.check_doc_alias_value(meta, doc_alias, hir_id, target, false, aliases)
787 self.tcx.sess.emit_err(errors::DocAliasMalformed { span: meta.span() });
792 fn check_doc_keyword(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
793 let doc_keyword = meta.value_str().unwrap_or(kw::Empty);
794 if doc_keyword == kw::Empty {
795 self.doc_attr_str_error(meta, "keyword");
798 match self.tcx.hir().find(hir_id).and_then(|node| match node {
799 hir::Node::Item(item) => Some(&item.kind),
802 Some(ItemKind::Mod(ref module)) => {
803 if !module.item_ids.is_empty() {
804 self.tcx.sess.emit_err(errors::DocKeywordEmptyMod { span: meta.span() });
809 self.tcx.sess.emit_err(errors::DocKeywordNotMod { span: meta.span() });
813 if !rustc_lexer::is_ident(doc_keyword.as_str()) {
814 self.tcx.sess.emit_err(errors::DocKeywordInvalidIdent {
815 span: meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
823 fn check_doc_fake_variadic(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
824 match self.tcx.hir().find(hir_id).and_then(|node| match node {
825 hir::Node::Item(item) => Some(&item.kind),
828 Some(ItemKind::Impl(ref i)) => {
829 let is_valid = matches!(&i.self_ty.kind, hir::TyKind::Tup([_]))
830 || if let hir::TyKind::BareFn(bare_fn_ty) = &i.self_ty.kind {
831 bare_fn_ty.decl.inputs.len() == 1
836 self.tcx.sess.emit_err(errors::DocFakeVariadicNotValid { span: meta.span() });
841 self.tcx.sess.emit_err(errors::DocKeywordOnlyImpl { span: meta.span() });
848 /// Checks `#[doc(inline)]`/`#[doc(no_inline)]` attributes. Returns `true` if valid.
850 /// A doc inlining attribute is invalid if it is applied to a non-`use` item, or
851 /// if there are conflicting attributes for one item.
853 /// `specified_inline` is used to keep track of whether we have
854 /// already seen an inlining attribute for this item.
855 /// If so, `specified_inline` holds the value and the span of
856 /// the first `inline`/`no_inline` attribute.
860 meta: &NestedMetaItem,
863 specified_inline: &mut Option<(bool, Span)>,
865 if target == Target::Use || target == Target::ExternCrate {
866 let do_inline = meta.name_or_empty() == sym::inline;
867 if let Some((prev_inline, prev_span)) = *specified_inline {
868 if do_inline != prev_inline {
869 let mut spans = MultiSpan::from_spans(vec![prev_span, meta.span()]);
870 spans.push_span_label(prev_span, fluent::passes_doc_inline_conflict_first);
871 spans.push_span_label(meta.span(), fluent::passes_doc_inline_conflict_second);
872 self.tcx.sess.emit_err(errors::DocKeywordConflict { spans });
877 *specified_inline = Some((do_inline, meta.span()));
881 self.tcx.emit_spanned_lint(
882 INVALID_DOC_ATTRIBUTES,
885 errors::DocInlineOnlyUse {
886 attr_span: meta.span(),
887 item_span: (attr.style == AttrStyle::Outer)
888 .then(|| self.tcx.hir().span(hir_id)),
895 /// Checks that an attribute is *not* used at the crate level. Returns `true` if valid.
896 fn check_attr_not_crate_level(
898 meta: &NestedMetaItem,
902 if CRATE_HIR_ID == hir_id {
903 self.tcx.sess.emit_err(errors::DocAttrNotCrateLevel { span: meta.span(), attr_name });
909 /// Checks that an attribute is used at the crate level. Returns `true` if valid.
910 fn check_attr_crate_level(
913 meta: &NestedMetaItem,
916 if hir_id != CRATE_HIR_ID {
917 self.tcx.struct_span_lint_hir(
918 INVALID_DOC_ATTRIBUTES,
921 fluent::passes_attr_crate_level,
923 if attr.style == AttrStyle::Outer
924 && self.tcx.hir().get_parent_item(hir_id) == CRATE_OWNER_ID
926 if let Ok(mut src) = self.tcx.sess.source_map().span_to_snippet(attr.span) {
928 err.span_suggestion_verbose(
932 Applicability::MaybeIncorrect,
935 err.span_help(attr.span, fluent::help);
938 err.note(fluent::note);
947 /// Checks that `doc(test(...))` attribute contains only valid attributes. Returns `true` if
949 fn check_test_attr(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
950 let mut is_valid = true;
951 if let Some(metas) = meta.meta_item_list() {
952 for i_meta in metas {
953 match i_meta.name_or_empty() {
954 sym::attr | sym::no_crate_inject => {}
956 self.tcx.emit_spanned_lint(
957 INVALID_DOC_ATTRIBUTES,
960 errors::DocTestUnknown {
961 path: rustc_ast_pretty::pprust::path_to_string(
962 &i_meta.meta_item().unwrap().path,
971 self.tcx.emit_spanned_lint(
972 INVALID_DOC_ATTRIBUTES,
975 errors::DocTestTakesList,
982 /// Check that the `#![doc(cfg_hide(...))]` attribute only contains a list of attributes.
983 /// Returns `true` if valid.
984 fn check_doc_cfg_hide(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
985 if meta.meta_item_list().is_some() {
988 self.tcx.emit_spanned_lint(
989 INVALID_DOC_ATTRIBUTES,
992 errors::DocCfgHideTakesList,
998 /// Runs various checks on `#[doc]` attributes. Returns `true` if valid.
1000 /// `specified_inline` should be initialized to `None` and kept for the scope
1001 /// of one item. Read the documentation of [`check_doc_inline`] for more information.
1003 /// [`check_doc_inline`]: Self::check_doc_inline
1009 specified_inline: &mut Option<(bool, Span)>,
1010 aliases: &mut FxHashMap<String, Span>,
1012 let mut is_valid = true;
1014 if let Some(mi) = attr.meta() && let Some(list) = mi.meta_item_list() {
1016 if let Some(i_meta) = meta.meta_item() {
1017 match i_meta.name_or_empty() {
1019 if !self.check_attr_not_crate_level(meta, hir_id, "alias")
1020 || !self.check_doc_alias(meta, hir_id, target, aliases) =>
1026 if !self.check_attr_not_crate_level(meta, hir_id, "keyword")
1027 || !self.check_doc_keyword(meta, hir_id) =>
1033 if !self.check_attr_not_crate_level(meta, hir_id, "fake_variadic")
1034 || !self.check_doc_fake_variadic(meta, hir_id) =>
1039 sym::html_favicon_url
1040 | sym::html_logo_url
1041 | sym::html_playground_url
1042 | sym::issue_tracker_base_url
1043 | sym::html_root_url
1044 | sym::html_no_source
1046 if !self.check_attr_crate_level(attr, meta, hir_id) =>
1052 if !self.check_attr_crate_level(attr, meta, hir_id)
1053 || !self.check_doc_cfg_hide(meta, hir_id) =>
1058 sym::inline | sym::no_inline
1059 if !self.check_doc_inline(
1070 // no_default_passes: deprecated
1071 // passes: deprecated
1072 // plugins: removed, but rustdoc warns about it itself
1077 | sym::html_favicon_url
1078 | sym::html_logo_url
1079 | sym::html_no_source
1080 | sym::html_playground_url
1081 | sym::html_root_url
1083 | sym::issue_tracker_base_url
1086 | sym::no_default_passes
1088 | sym::notable_trait
1091 | sym::fake_variadic => {}
1094 if !self.check_test_attr(meta, hir_id) {
1100 if !self.tcx.features().rustdoc_internals {
1101 self.tcx.emit_spanned_lint(
1102 INVALID_DOC_ATTRIBUTES,
1105 errors::DocPrimitive,
1111 let path = rustc_ast_pretty::pprust::path_to_string(&i_meta.path);
1112 if i_meta.has_name(sym::spotlight) {
1113 self.tcx.emit_spanned_lint(
1114 INVALID_DOC_ATTRIBUTES,
1117 errors::DocTestUnknownSpotlight {
1122 } else if i_meta.has_name(sym::include) &&
1123 let Some(value) = i_meta.value_str() {
1124 let applicability = if list.len() == 1 {
1125 Applicability::MachineApplicable
1127 Applicability::MaybeIncorrect
1129 // If there are multiple attributes, the suggestion would suggest
1130 // deleting all of them, which is incorrect.
1131 self.tcx.emit_spanned_lint(
1132 INVALID_DOC_ATTRIBUTES,
1135 errors::DocTestUnknownInclude {
1137 value: value.to_string(),
1138 inner: if attr.style == AttrStyle::Inner { "!" } else { "" },
1139 sugg: (attr.meta().unwrap().span, applicability),
1143 self.tcx.emit_spanned_lint(
1144 INVALID_DOC_ATTRIBUTES,
1147 errors::DocTestUnknownAny { path }
1154 self.tcx.emit_spanned_lint(
1155 INVALID_DOC_ATTRIBUTES,
1168 /// Warns against some misuses of `#[pass_by_value]`
1169 fn check_pass_by_value(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1171 Target::Struct | Target::Enum | Target::TyAlias => true,
1173 self.tcx.sess.emit_err(errors::PassByValue { attr_span: attr.span, span });
1179 fn check_allow_incoherent_impl(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1181 Target::Method(MethodKind::Inherent) => true,
1183 self.tcx.sess.emit_err(errors::AllowIncoherentImpl { attr_span: attr.span, span });
1189 fn check_has_incoherent_inherent_impls(
1196 Target::Trait | Target::Struct | Target::Enum | Target::Union | Target::ForeignTy => {
1202 .emit_err(errors::HasIncoherentInherentImpl { attr_span: attr.span, span });
1208 /// Warns against some misuses of `#[must_use]`
1209 fn check_must_use(&self, hir_id: HirId, attr: &Attribute, target: Target) -> bool {
1218 // `impl Trait` in return position can trip
1219 // `unused_must_use` if `Trait` is marked as
1223 let article = match target {
1228 | Target::Expression
1230 | Target::AssocConst
1231 | Target::AssocTy => "an",
1235 self.tcx.emit_spanned_lint(
1239 errors::MustUseNoEffect { article, target },
1243 // For now, its always valid
1247 /// Checks if `#[must_not_suspend]` is applied to a function. Returns `true` if valid.
1248 fn check_must_not_suspend(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1250 Target::Struct | Target::Enum | Target::Union | Target::Trait => true,
1252 self.tcx.sess.emit_err(errors::MustNotSuspend { attr_span: attr.span, span });
1258 /// Checks if `#[cold]` is applied to a non-function. Returns `true` if valid.
1259 fn check_cold(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1261 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => {}
1262 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1263 // `#[cold]` attribute with just a lint, because we previously
1264 // erroneously allowed it and some crates used it accidentally, to be compatible
1265 // with crates depending on them, we can't throw an error here.
1266 Target::Field | Target::Arm | Target::MacroDef => {
1267 self.inline_attr_str_error_with_macro_def(hir_id, attr, "cold");
1270 // FIXME: #[cold] was previously allowed on non-functions and some crates used
1271 // this, so only emit a warning.
1272 self.tcx.emit_spanned_lint(
1276 errors::Cold { span, on_crate: hir_id == CRATE_HIR_ID },
1282 /// Checks if `#[link]` is applied to an item other than a foreign module.
1283 fn check_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1284 if target == Target::ForeignMod
1285 && let hir::Node::Item(item) = self.tcx.hir().get(hir_id)
1286 && let Item { kind: ItemKind::ForeignMod { abi, .. }, .. } = item
1287 && !matches!(abi, Abi::Rust | Abi::RustIntrinsic | Abi::PlatformIntrinsic)
1292 self.tcx.emit_spanned_lint(
1296 errors::Link { span: (target != Target::ForeignMod).then_some(span) },
1300 /// Checks if `#[link_name]` is applied to an item other than a foreign function or static.
1301 fn check_link_name(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1303 Target::ForeignFn | Target::ForeignStatic => {}
1304 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1305 // `#[link_name]` attribute with just a lint, because we previously
1306 // erroneously allowed it and some crates used it accidentally, to be compatible
1307 // with crates depending on them, we can't throw an error here.
1308 Target::Field | Target::Arm | Target::MacroDef => {
1309 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_name");
1312 // FIXME: #[cold] was previously allowed on non-functions/statics and some crates
1313 // used this, so only emit a warning.
1314 let attr_span = matches!(target, Target::ForeignMod).then_some(attr.span);
1315 if let Some(s) = attr.value_str() {
1316 self.tcx.emit_spanned_lint(
1320 errors::LinkName { span, attr_span, value: s.as_str() },
1323 self.tcx.emit_spanned_lint(
1327 errors::LinkName { span, attr_span, value: "..." },
1334 /// Checks if `#[no_link]` is applied to an `extern crate`. Returns `true` if valid.
1335 fn check_no_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
1337 Target::ExternCrate => true,
1338 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1339 // `#[no_link]` 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, "no_link");
1347 self.tcx.sess.emit_err(errors::NoLink { attr_span: attr.span, span });
1353 fn is_impl_item(&self, hir_id: HirId) -> bool {
1354 matches!(self.tcx.hir().get(hir_id), hir::Node::ImplItem(..))
1357 /// Checks if `#[export_name]` is applied to a function or static. Returns `true` if valid.
1358 fn check_export_name(
1366 Target::Static | Target::Fn => true,
1367 Target::Method(..) if self.is_impl_item(hir_id) => true,
1368 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1369 // `#[export_name]` attribute with just a lint, because we previously
1370 // erroneously allowed it and some crates used it accidentally, to be compatible
1371 // with crates depending on them, we can't throw an error here.
1372 Target::Field | Target::Arm | Target::MacroDef => {
1373 self.inline_attr_str_error_with_macro_def(hir_id, attr, "export_name");
1377 self.tcx.sess.emit_err(errors::ExportName { attr_span: attr.span, span });
1383 fn check_rustc_layout_scalar_valid_range(
1389 if target != Target::Struct {
1390 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeNotStruct {
1391 attr_span: attr.span,
1397 let Some(list) = attr.meta_item_list() else {
1401 if matches!(&list[..], &[NestedMetaItem::Lit(MetaItemLit { kind: LitKind::Int(..), .. })]) {
1404 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeArg { attr_span: attr.span });
1409 /// Checks if `#[rustc_legacy_const_generics]` is applied to a function and has a valid argument.
1410 fn check_rustc_legacy_const_generics(
1416 item: Option<ItemLike<'_>>,
1418 let is_function = matches!(target, Target::Fn);
1420 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1421 attr_span: attr.span,
1423 on_crate: hir_id == CRATE_HIR_ID,
1428 let Some(list) = attr.meta_item_list() else {
1429 // The attribute form is validated on AST.
1433 let Some(ItemLike::Item(Item {
1434 kind: ItemKind::Fn(FnSig { decl, .. }, generics, _),
1437 bug!("should be a function item");
1440 for param in generics.params {
1442 hir::GenericParamKind::Const { .. } => {}
1444 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsOnly {
1445 attr_span: attr.span,
1446 param_span: param.span,
1453 if list.len() != generics.params.len() {
1454 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndex {
1455 attr_span: attr.span,
1456 generics_span: generics.span,
1461 let arg_count = decl.inputs.len() as u128 + generics.params.len() as u128;
1462 let mut invalid_args = vec![];
1464 if let Some(LitKind::Int(val, _)) = meta.lit().map(|lit| &lit.kind) {
1465 if *val >= arg_count {
1466 let span = meta.span();
1467 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexExceed {
1469 arg_count: arg_count as usize,
1474 invalid_args.push(meta.span());
1478 if !invalid_args.is_empty() {
1479 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexNegative { invalid_args });
1486 /// Helper function for checking that the provided attribute is only applied to a function or
1488 fn check_applied_to_fn_or_method(
1495 let is_function = matches!(target, Target::Fn | Target::Method(..));
1497 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1498 attr_span: attr.span,
1500 on_crate: hir_id == CRATE_HIR_ID,
1508 /// Checks that the `#[rustc_lint_query_instability]` attribute is only applied to a function
1510 fn check_rustc_lint_query_instability(
1517 self.check_applied_to_fn_or_method(hir_id, attr, span, target)
1520 /// Checks that the `#[rustc_lint_diagnostics]` attribute is only applied to a function or
1522 fn check_rustc_lint_diagnostics(
1529 self.check_applied_to_fn_or_method(hir_id, attr, span, target)
1532 /// Checks that the `#[rustc_lint_opt_ty]` attribute is only applied to a struct.
1533 fn check_rustc_lint_opt_ty(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1535 Target::Struct => true,
1537 self.tcx.sess.emit_err(errors::RustcLintOptTy { attr_span: attr.span, span });
1543 /// Checks that the `#[rustc_lint_opt_deny_field_access]` attribute is only applied to a field.
1544 fn check_rustc_lint_opt_deny_field_access(
1551 Target::Field => true,
1555 .emit_err(errors::RustcLintOptDenyFieldAccess { attr_span: attr.span, span });
1561 /// Checks that the dep-graph debugging attributes are only present when the query-dep-graph
1562 /// option is passed to the compiler.
1563 fn check_rustc_dirty_clean(&self, attr: &Attribute) -> bool {
1564 if self.tcx.sess.opts.unstable_opts.query_dep_graph {
1567 self.tcx.sess.emit_err(errors::RustcDirtyClean { span: attr.span });
1572 /// Checks if `#[link_section]` is applied to a function or static.
1573 fn check_link_section(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1575 Target::Static | Target::Fn | Target::Method(..) => {}
1576 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1577 // `#[link_section]` attribute with just a lint, because we previously
1578 // erroneously allowed it and some crates used it accidentally, to be compatible
1579 // with crates depending on them, we can't throw an error here.
1580 Target::Field | Target::Arm | Target::MacroDef => {
1581 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_section");
1584 // FIXME: #[link_section] was previously allowed on non-functions/statics and some
1585 // crates used this, so only emit a warning.
1586 self.tcx.emit_spanned_lint(
1590 errors::LinkSection { span },
1596 /// Checks if `#[no_mangle]` is applied to a function or static.
1597 fn check_no_mangle(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1599 Target::Static | Target::Fn => {}
1600 Target::Method(..) if self.is_impl_item(hir_id) => {}
1601 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1602 // `#[no_mangle]` attribute with just a lint, because we previously
1603 // erroneously allowed it and some crates used it accidentally, to be compatible
1604 // with crates depending on them, we can't throw an error here.
1605 Target::Field | Target::Arm | Target::MacroDef => {
1606 self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_mangle");
1608 // FIXME: #[no_mangle] was previously allowed on non-functions/statics, this should be an error
1609 // The error should specify that the item that is wrong is specifically a *foreign* fn/static
1610 // otherwise the error seems odd
1611 Target::ForeignFn | Target::ForeignStatic => {
1612 let foreign_item_kind = match target {
1613 Target::ForeignFn => "function",
1614 Target::ForeignStatic => "static",
1615 _ => unreachable!(),
1617 self.tcx.emit_spanned_lint(
1621 errors::NoMangleForeign { span, attr_span: attr.span, foreign_item_kind },
1625 // FIXME: #[no_mangle] was previously allowed on non-functions/statics and some
1626 // crates used this, so only emit a warning.
1627 self.tcx.emit_spanned_lint(
1631 errors::NoMangle { span },
1637 /// Checks if the `#[repr]` attributes on `item` are valid.
1640 attrs: &[Attribute],
1643 item: Option<ItemLike<'_>>,
1646 // Extract the names of all repr hints, e.g., [foo, bar, align] for:
1649 // #[repr(bar, align(8))]
1651 let hints: Vec<_> = attrs
1653 .filter(|attr| attr.has_name(sym::repr))
1654 .filter_map(|attr| attr.meta_item_list())
1658 let mut int_reprs = 0;
1659 let mut is_c = false;
1660 let mut is_simd = false;
1661 let mut is_transparent = false;
1663 for hint in &hints {
1664 if !hint.is_meta_item() {
1665 self.tcx.sess.emit_err(errors::ReprIdent { span: hint.span() });
1669 match hint.name_or_empty() {
1673 Target::Struct | Target::Union | Target::Enum => continue,
1675 self.tcx.sess.emit_err(AttrApplication::StructEnumUnion {
1676 hint_span: hint.span(),
1683 if let (Target::Fn, false) = (target, self.tcx.features().fn_align) {
1685 &self.tcx.sess.parse_sess,
1688 "`repr(align)` attributes on functions are unstable",
1694 Target::Struct | Target::Union | Target::Enum | Target::Fn => continue,
1696 self.tcx.sess.emit_err(AttrApplication::StructEnumFunctionUnion {
1697 hint_span: hint.span(),
1704 if target != Target::Struct && target != Target::Union {
1705 self.tcx.sess.emit_err(AttrApplication::StructUnion {
1706 hint_span: hint.span(),
1715 if target != Target::Struct {
1718 .emit_err(AttrApplication::Struct { hint_span: hint.span(), span });
1723 sym::transparent => {
1724 is_transparent = true;
1726 Target::Struct | Target::Union | Target::Enum => continue,
1728 self.tcx.sess.emit_err(AttrApplication::StructEnumUnion {
1729 hint_span: hint.span(),
1748 if target != Target::Enum {
1751 .emit_err(AttrApplication::Enum { hint_span: hint.span(), span });
1757 self.tcx.sess.emit_err(UnrecognizedReprHint { span: hint.span() });
1763 // Just point at all repr hints if there are any incompatibilities.
1764 // This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
1765 let hint_spans = hints.iter().map(|hint| hint.span());
1767 // Error on repr(transparent, <anything else>).
1768 if is_transparent && hints.len() > 1 {
1769 let hint_spans: Vec<_> = hint_spans.clone().collect();
1772 .emit_err(TransparentIncompatible { hint_spans, target: target.to_string() });
1774 // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
1776 || (is_simd && is_c)
1779 && item.map_or(false, |item| {
1780 if let ItemLike::Item(item) = item {
1781 return is_c_like_enum(item);
1786 self.tcx.emit_spanned_lint(
1787 CONFLICTING_REPR_HINTS,
1789 hint_spans.collect::<Vec<Span>>(),
1790 errors::ReprConflicting,
1795 fn check_used(&self, attrs: &[Attribute], target: Target) {
1796 let mut used_linker_span = None;
1797 let mut used_compiler_span = None;
1798 for attr in attrs.iter().filter(|attr| attr.has_name(sym::used)) {
1799 if target != Target::Static {
1800 self.tcx.sess.emit_err(errors::UsedStatic { span: attr.span });
1802 let inner = attr.meta_item_list();
1803 match inner.as_deref() {
1804 Some([item]) if item.has_name(sym::linker) => {
1805 if used_linker_span.is_none() {
1806 used_linker_span = Some(attr.span);
1809 Some([item]) if item.has_name(sym::compiler) => {
1810 if used_compiler_span.is_none() {
1811 used_compiler_span = Some(attr.span);
1815 // This error case is handled in rustc_hir_analysis::collect.
1818 // Default case (compiler) when arg isn't defined.
1819 if used_compiler_span.is_none() {
1820 used_compiler_span = Some(attr.span);
1825 if let (Some(linker_span), Some(compiler_span)) = (used_linker_span, used_compiler_span) {
1828 .emit_err(errors::UsedCompilerLinker { spans: vec![linker_span, compiler_span] });
1832 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1833 /// (Allows proc_macro functions)
1834 fn check_allow_internal_unstable(
1840 attrs: &[Attribute],
1842 debug!("Checking target: {:?}", target);
1846 if self.tcx.sess.is_proc_macro_attr(attr) {
1847 debug!("Is proc macro attr");
1851 debug!("Is not proc macro attr");
1854 Target::MacroDef => true,
1855 // FIXME(#80564): We permit struct fields and match arms to have an
1856 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1857 // erroneously allowed it and some crates used it accidentally, to be compatible
1858 // with crates depending on them, we can't throw an error here.
1859 Target::Field | Target::Arm => {
1860 self.inline_attr_str_error_without_macro_def(
1863 "allow_internal_unstable",
1870 .emit_err(errors::AllowInternalUnstable { attr_span: attr.span, span });
1876 /// Checks if the items on the `#[debugger_visualizer]` attribute are valid.
1877 fn check_debugger_visualizer(&self, attr: &Attribute, target: Target) -> bool {
1881 self.tcx.sess.emit_err(errors::DebugVisualizerPlacement { span: attr.span });
1886 let Some(hints) = attr.meta_item_list() else {
1887 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1891 let hint = match hints.len() {
1894 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1899 let Some(meta_item) = hint.meta_item() else {
1900 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1904 let visualizer_path = match (meta_item.name_or_empty(), meta_item.value_str()) {
1905 (sym::natvis_file, Some(value)) => value,
1906 (sym::gdb_script_file, Some(value)) => value,
1908 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: meta_item.span });
1914 match resolve_path(&self.tcx.sess.parse_sess, visualizer_path.as_str(), attr.span) {
1922 match std::fs::File::open(&file) {
1925 self.tcx.sess.emit_err(DebugVisualizerUnreadable {
1926 span: meta_item.span,
1935 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1936 /// (Allows proc_macro functions)
1937 fn check_rustc_allow_const_fn_unstable(
1945 Target::Fn | Target::Method(_)
1946 if self.tcx.is_const_fn_raw(self.tcx.hir().local_def_id(hir_id).to_def_id()) =>
1950 // FIXME(#80564): We permit struct fields and match arms to have an
1951 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1952 // erroneously allowed it and some crates used it accidentally, to be compatible
1953 // with crates depending on them, we can't throw an error here.
1954 Target::Field | Target::Arm | Target::MacroDef => {
1955 self.inline_attr_str_error_with_macro_def(hir_id, attr, "allow_internal_unstable");
1961 .emit_err(errors::RustcAllowConstFnUnstable { attr_span: attr.span, span });
1967 fn check_rustc_std_internal_symbol(
1974 Target::Fn | Target::Static => true,
1978 .emit_err(errors::RustcStdInternalSymbol { attr_span: attr.span, span });
1984 /// `#[const_trait]` only applies to traits.
1985 fn check_const_trait(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1987 Target::Trait => true,
1989 self.tcx.sess.emit_err(errors::ConstTrait { attr_span: attr.span });
1995 fn check_stability_promotable(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1997 Target::Expression => {
1998 self.tcx.sess.emit_err(errors::StabilityPromotable { attr_span: attr.span });
2005 fn check_link_ordinal(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
2007 Target::ForeignFn | Target::ForeignStatic => true,
2009 self.tcx.sess.emit_err(errors::LinkOrdinal { attr_span: attr.span });
2015 fn check_deprecated(&self, hir_id: HirId, attr: &Attribute, _span: Span, target: Target) {
2017 Target::Closure | Target::Expression | Target::Statement | Target::Arm => {
2018 self.tcx.emit_spanned_lint(
2029 fn check_macro_use(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2030 let name = attr.name_or_empty();
2032 Target::ExternCrate | Target::Mod => {}
2034 self.tcx.emit_spanned_lint(
2038 errors::MacroUse { name },
2044 fn check_macro_export(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2045 if target != Target::MacroDef {
2046 self.tcx.emit_spanned_lint(UNUSED_ATTRIBUTES, hir_id, attr.span, errors::MacroExport);
2050 fn check_plugin_registrar(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2051 if target != Target::Fn {
2052 self.tcx.emit_spanned_lint(
2056 errors::PluginRegistrar,
2061 fn check_unused_attribute(&self, hir_id: HirId, attr: &Attribute) {
2062 // Warn on useless empty attributes.
2063 let note = if matches!(
2064 attr.name_or_empty(),
2073 | sym::target_feature
2074 ) && attr.meta_item_list().map_or(false, |list| list.is_empty())
2076 errors::UnusedNote::EmptyList { name: attr.name_or_empty() }
2078 attr.name_or_empty(),
2079 sym::allow | sym::warn | sym::deny | sym::forbid | sym::expect
2080 ) && let Some(meta) = attr.meta_item_list()
2082 && let Some(item) = meta[0].meta_item()
2083 && let MetaItemKind::NameValue(_) = &item.kind
2084 && item.path == sym::reason
2086 errors::UnusedNote::NoLints { name: attr.name_or_empty() }
2087 } else if attr.name_or_empty() == sym::default_method_body_is_const {
2088 errors::UnusedNote::DefaultMethodBodyConst
2093 self.tcx.emit_spanned_lint(
2097 errors::Unused { attr_span: attr.span, note },
2101 /// A best effort attempt to create an error for a mismatching proc macro signature.
2103 /// If this best effort goes wrong, it will just emit a worse error later (see #102923)
2104 fn check_proc_macro(&self, hir_id: HirId, target: Target, kind: ProcMacroKind) {
2105 let expected_input_count = match kind {
2106 ProcMacroKind::Attribute => 2,
2107 ProcMacroKind::Derive | ProcMacroKind::FunctionLike => 1,
2110 let expected_signature = match kind {
2111 ProcMacroKind::Attribute => "fn(TokenStream, TokenStream) -> TokenStream",
2112 ProcMacroKind::Derive | ProcMacroKind::FunctionLike => "fn(TokenStream) -> TokenStream",
2116 if target == Target::Fn {
2117 let Some(tokenstream) = tcx.get_diagnostic_item(sym::TokenStream) else {return};
2118 let tokenstream = tcx.type_of(tokenstream);
2120 let id = hir_id.expect_owner();
2121 let hir_sig = tcx.hir().fn_sig_by_hir_id(hir_id).unwrap();
2123 let sig = tcx.liberate_late_bound_regions(id.to_def_id(), tcx.fn_sig(id));
2124 let sig = tcx.normalize_erasing_regions(ParamEnv::empty(), sig);
2126 // We don't currently require that the function signature is equal to
2127 // `fn(TokenStream) -> TokenStream`, but instead monomorphizes to
2128 // `fn(TokenStream) -> TokenStream` after some substitution of generic arguments.
2130 // Properly checking this means pulling in additional `rustc` crates, so we don't.
2131 let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::AsInfer };
2133 if sig.abi != Abi::Rust {
2134 tcx.sess.emit_err(ProcMacroInvalidAbi { span: hir_sig.span, abi: sig.abi.name() });
2135 self.abort.set(true);
2138 if sig.unsafety == Unsafety::Unsafe {
2139 tcx.sess.emit_err(ProcMacroUnsafe { span: hir_sig.span });
2140 self.abort.set(true);
2143 let output = sig.output();
2145 // Typecheck the output
2146 if !drcx.types_may_unify(output, tokenstream) {
2147 tcx.sess.emit_err(ProcMacroTypeError {
2148 span: hir_sig.decl.output.span(),
2153 self.abort.set(true);
2156 if sig.inputs().len() < expected_input_count {
2157 tcx.sess.emit_err(ProcMacroMissingArguments {
2158 expected_input_count,
2163 self.abort.set(true);
2166 // Check that the inputs are correct, if there are enough.
2167 if sig.inputs().len() >= expected_input_count {
2169 sig.inputs().iter().zip(hir_sig.decl.inputs).take(expected_input_count)
2171 if !drcx.types_may_unify(*arg, tokenstream) {
2172 tcx.sess.emit_err(ProcMacroTypeError {
2178 self.abort.set(true);
2183 // Check that there are not too many arguments
2184 let body_id = tcx.hir().body_owned_by(id.def_id);
2185 let excess = tcx.hir().body(body_id).params.get(expected_input_count..);
2186 if let Some(excess @ [begin @ end] | excess @ [begin, .., end]) = excess {
2187 tcx.sess.emit_err(ProcMacroDiffArguments {
2188 span: begin.span.to(end.span),
2189 count: excess.len(),
2193 self.abort.set(true);
2199 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {
2200 type NestedFilter = nested_filter::OnlyBodies;
2202 fn nested_visit_map(&mut self) -> Self::Map {
2206 fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
2207 // Historically we've run more checks on non-exported than exported macros,
2208 // so this lets us continue to run them while maintaining backwards compatibility.
2209 // In the long run, the checks should be harmonized.
2210 if let ItemKind::Macro(ref macro_def, _) = item.kind {
2211 let def_id = item.owner_id.to_def_id();
2212 if macro_def.macro_rules && !self.tcx.has_attr(def_id, sym::macro_export) {
2213 check_non_exported_macro_for_invalid_attrs(self.tcx, item);
2217 let target = Target::from_item(item);
2218 self.check_attributes(item.hir_id(), item.span, target, Some(ItemLike::Item(item)));
2219 intravisit::walk_item(self, item)
2222 fn visit_generic_param(&mut self, generic_param: &'tcx hir::GenericParam<'tcx>) {
2223 let target = Target::from_generic_param(generic_param);
2224 self.check_attributes(generic_param.hir_id, generic_param.span, target, None);
2225 intravisit::walk_generic_param(self, generic_param)
2228 fn visit_trait_item(&mut self, trait_item: &'tcx TraitItem<'tcx>) {
2229 let target = Target::from_trait_item(trait_item);
2230 self.check_attributes(trait_item.hir_id(), trait_item.span, target, None);
2231 intravisit::walk_trait_item(self, trait_item)
2234 fn visit_field_def(&mut self, struct_field: &'tcx hir::FieldDef<'tcx>) {
2235 self.check_attributes(struct_field.hir_id, struct_field.span, Target::Field, None);
2236 intravisit::walk_field_def(self, struct_field);
2239 fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
2240 self.check_attributes(arm.hir_id, arm.span, Target::Arm, None);
2241 intravisit::walk_arm(self, arm);
2244 fn visit_foreign_item(&mut self, f_item: &'tcx ForeignItem<'tcx>) {
2245 let target = Target::from_foreign_item(f_item);
2246 self.check_attributes(f_item.hir_id(), f_item.span, target, Some(ItemLike::ForeignItem));
2247 intravisit::walk_foreign_item(self, f_item)
2250 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
2251 let target = target_from_impl_item(self.tcx, impl_item);
2252 self.check_attributes(impl_item.hir_id(), impl_item.span, target, None);
2253 intravisit::walk_impl_item(self, impl_item)
2256 fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt<'tcx>) {
2257 // When checking statements ignore expressions, they will be checked later.
2258 if let hir::StmtKind::Local(ref l) = stmt.kind {
2259 self.check_attributes(l.hir_id, stmt.span, Target::Statement, None);
2261 intravisit::walk_stmt(self, stmt)
2264 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
2265 let target = match expr.kind {
2266 hir::ExprKind::Closure { .. } => Target::Closure,
2267 _ => Target::Expression,
2270 self.check_attributes(expr.hir_id, expr.span, target, None);
2271 intravisit::walk_expr(self, expr)
2274 fn visit_expr_field(&mut self, field: &'tcx hir::ExprField<'tcx>) {
2275 self.check_attributes(field.hir_id, field.span, Target::ExprField, None);
2276 intravisit::walk_expr_field(self, field)
2279 fn visit_variant(&mut self, variant: &'tcx hir::Variant<'tcx>) {
2280 self.check_attributes(variant.hir_id, variant.span, Target::Variant, None);
2281 intravisit::walk_variant(self, variant)
2284 fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {
2285 self.check_attributes(param.hir_id, param.span, Target::Param, None);
2287 intravisit::walk_param(self, param);
2290 fn visit_pat_field(&mut self, field: &'tcx hir::PatField<'tcx>) {
2291 self.check_attributes(field.hir_id, field.span, Target::PatField, None);
2292 intravisit::walk_pat_field(self, field);
2296 fn is_c_like_enum(item: &Item<'_>) -> bool {
2297 if let ItemKind::Enum(ref def, _) = item.kind {
2298 for variant in def.variants {
2299 match variant.data {
2300 hir::VariantData::Unit(..) => { /* continue */ }
2310 // FIXME: Fix "Cannot determine resolution" error and remove built-in macros
2312 fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
2313 // Check for builtin attributes at the crate level
2314 // which were unsuccessfully resolved due to cannot determine
2315 // resolution for the attribute macro error.
2316 const ATTRS_TO_CHECK: &[Symbol] = &[
2320 sym::automatically_derived,
2327 sym::global_allocator,
2332 // This function should only be called with crate attributes
2333 // which are inner attributes always but lets check to make sure
2334 if attr.style == AttrStyle::Inner {
2335 for attr_to_check in ATTRS_TO_CHECK {
2336 if attr.has_name(*attr_to_check) {
2337 tcx.sess.emit_err(InvalidAttrAtCrateLevel {
2339 snippet: tcx.sess.source_map().span_to_snippet(attr.span).ok(),
2340 name: *attr_to_check,
2348 fn check_non_exported_macro_for_invalid_attrs(tcx: TyCtxt<'_>, item: &Item<'_>) {
2349 let attrs = tcx.hir().attrs(item.hir_id());
2352 if attr.has_name(sym::inline) {
2353 tcx.sess.emit_err(errors::NonExportedMacroInvalidAttrs { attr_span: attr.span });
2358 fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
2359 let check_attr_visitor = &mut CheckAttrVisitor { tcx, abort: Cell::new(false) };
2360 tcx.hir().visit_item_likes_in_module(module_def_id, check_attr_visitor);
2361 if module_def_id.is_top_level_module() {
2362 check_attr_visitor.check_attributes(CRATE_HIR_ID, DUMMY_SP, Target::Mod, None);
2363 check_invalid_crate_level_attr(tcx, tcx.hir().krate_attrs());
2365 if check_attr_visitor.abort.get() {
2366 tcx.sess.abort_if_errors()
2370 pub(crate) fn provide(providers: &mut Providers) {
2371 *providers = Providers { check_mod_attrs, ..*providers };
2374 fn check_duplicates(
2378 duplicates: AttributeDuplicates,
2379 seen: &mut FxHashMap<Symbol, Span>,
2381 use AttributeDuplicates::*;
2382 if matches!(duplicates, WarnFollowingWordOnly) && !attr.is_word() {
2387 WarnFollowing | FutureWarnFollowing | WarnFollowingWordOnly | FutureWarnPreceding => {
2388 match seen.entry(attr.name_or_empty()) {
2389 Entry::Occupied(mut entry) => {
2390 let (this, other) = if matches!(duplicates, FutureWarnPreceding) {
2391 let to_remove = entry.insert(attr.span);
2392 (to_remove, attr.span)
2394 (attr.span, *entry.get())
2396 tcx.emit_spanned_lint(
2400 errors::UnusedDuplicate {
2405 FutureWarnFollowing | FutureWarnPreceding
2411 Entry::Vacant(entry) => {
2412 entry.insert(attr.span);
2416 ErrorFollowing | ErrorPreceding => match seen.entry(attr.name_or_empty()) {
2417 Entry::Occupied(mut entry) => {
2418 let (this, other) = if matches!(duplicates, ErrorPreceding) {
2419 let to_remove = entry.insert(attr.span);
2420 (to_remove, attr.span)
2422 (attr.span, *entry.get())
2424 tcx.sess.emit_err(errors::UnusedMultiple {
2427 name: attr.name_or_empty(),
2430 Entry::Vacant(entry) => {
2431 entry.insert(attr.span);