1 //! This module implements some validity checks for attributes.
2 //! In particular it verifies that `#[inline]` and `#[repr]` attributes are
3 //! attached to items that actually support them and if there are
4 //! conflicts between multiple such attributes attached to the same
8 self, AttrApplication
, DebugVisualizerUnreadable
, InvalidAttrAtCrateLevel
, ObjectLifetimeErr
,
9 OnlyHasEffectOn
, TransparentIncompatible
, UnrecognizedReprHint
,
11 use rustc_ast
::{ast, AttrStyle, Attribute, Lit, LitKind, MetaItemKind, NestedMetaItem}
;
12 use rustc_data_structures
::fx
::FxHashMap
;
13 use rustc_errors
::{fluent, Applicability, MultiSpan}
;
14 use rustc_expand
::base
::resolve_path
;
15 use rustc_feature
::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP}
;
17 use rustc_hir
::def_id
::LocalDefId
;
18 use rustc_hir
::intravisit
::{self, Visitor}
;
20 self, FnSig
, ForeignItem
, HirId
, Item
, ItemKind
, TraitItem
, CRATE_HIR_ID
, CRATE_OWNER_ID
,
22 use rustc_hir
::{MethodKind, Target}
;
23 use rustc_middle
::hir
::nested_filter
;
24 use rustc_middle
::middle
::resolve_lifetime
::ObjectLifetimeDefault
;
25 use rustc_middle
::ty
::query
::Providers
;
26 use rustc_middle
::ty
::TyCtxt
;
27 use rustc_session
::lint
::builtin
::{
28 CONFLICTING_REPR_HINTS
, INVALID_DOC_ATTRIBUTES
, UNUSED_ATTRIBUTES
,
30 use rustc_session
::parse
::feature_err
;
31 use rustc_span
::symbol
::{kw, sym, Symbol}
;
32 use rustc_span
::{Span, DUMMY_SP}
;
33 use rustc_target
::spec
::abi
::Abi
;
34 use std
::collections
::hash_map
::Entry
;
36 pub(crate) fn target_from_impl_item
<'tcx
>(
38 impl_item
: &hir
::ImplItem
<'_
>,
40 match impl_item
.kind
{
41 hir
::ImplItemKind
::Const(..) => Target
::AssocConst
,
42 hir
::ImplItemKind
::Fn(..) => {
43 let parent_def_id
= tcx
.hir().get_parent_item(impl_item
.hir_id()).def_id
;
44 let containing_item
= tcx
.hir().expect_item(parent_def_id
);
45 let containing_impl_is_for_trait
= match &containing_item
.kind
{
46 hir
::ItemKind
::Impl(impl_
) => impl_
.of_trait
.is_some(),
47 _
=> bug
!("parent of an ImplItem must be an Impl"),
49 if containing_impl_is_for_trait
{
50 Target
::Method(MethodKind
::Trait { body: true }
)
52 Target
::Method(MethodKind
::Inherent
)
55 hir
::ImplItemKind
::Type(..) => Target
::AssocTy
,
59 #[derive(Clone, Copy)]
61 Item(&'tcx Item
<'tcx
>),
65 struct CheckAttrVisitor
<'tcx
> {
69 impl CheckAttrVisitor
<'_
> {
70 /// Checks any attribute.
76 item
: Option
<ItemLike
<'_
>>,
78 let mut doc_aliases
= FxHashMap
::default();
79 let mut is_valid
= true;
80 let mut specified_inline
= None
;
81 let mut seen
= FxHashMap
::default();
82 let attrs
= self.tcx
.hir().attrs(hir_id
);
84 let attr_is_valid
= match attr
.name_or_empty() {
85 sym
::inline
=> self.check_inline(hir_id
, attr
, span
, target
),
86 sym
::no_coverage
=> self.check_no_coverage(hir_id
, attr
, span
, target
),
87 sym
::non_exhaustive
=> self.check_non_exhaustive(hir_id
, attr
, span
, target
),
88 sym
::marker
=> self.check_marker(hir_id
, attr
, span
, target
),
89 sym
::rustc_must_implement_one_of
=> {
90 self.check_rustc_must_implement_one_of(attr
, span
, target
)
92 sym
::target_feature
=> self.check_target_feature(hir_id
, attr
, span
, target
),
93 sym
::thread_local
=> self.check_thread_local(attr
, span
, target
),
94 sym
::track_caller
=> {
95 self.check_track_caller(hir_id
, attr
.span
, attrs
, span
, target
)
97 sym
::doc
=> self.check_doc_attrs(
101 &mut specified_inline
,
104 sym
::no_link
=> self.check_no_link(hir_id
, &attr
, span
, target
),
105 sym
::export_name
=> self.check_export_name(hir_id
, &attr
, span
, target
),
106 sym
::rustc_layout_scalar_valid_range_start
107 | sym
::rustc_layout_scalar_valid_range_end
=> {
108 self.check_rustc_layout_scalar_valid_range(&attr
, span
, target
)
110 sym
::allow_internal_unstable
=> {
111 self.check_allow_internal_unstable(hir_id
, &attr
, span
, target
, &attrs
)
113 sym
::debugger_visualizer
=> self.check_debugger_visualizer(&attr
, target
),
114 sym
::rustc_allow_const_fn_unstable
=> {
115 self.check_rustc_allow_const_fn_unstable(hir_id
, &attr
, span
, target
)
117 sym
::rustc_std_internal_symbol
=> {
118 self.check_rustc_std_internal_symbol(&attr
, span
, target
)
120 sym
::naked
=> self.check_naked(hir_id
, attr
, span
, target
),
121 sym
::rustc_legacy_const_generics
=> {
122 self.check_rustc_legacy_const_generics(&attr
, span
, target
, item
)
124 sym
::rustc_lint_query_instability
=> {
125 self.check_rustc_lint_query_instability(&attr
, span
, target
)
127 sym
::rustc_lint_diagnostics
=> {
128 self.check_rustc_lint_diagnostics(&attr
, span
, target
)
130 sym
::rustc_lint_opt_ty
=> self.check_rustc_lint_opt_ty(&attr
, span
, target
),
131 sym
::rustc_lint_opt_deny_field_access
=> {
132 self.check_rustc_lint_opt_deny_field_access(&attr
, span
, target
)
136 | sym
::rustc_if_this_changed
137 | sym
::rustc_then_this_would_need
=> self.check_rustc_dirty_clean(&attr
),
138 sym
::cmse_nonsecure_entry
=> self.check_cmse_nonsecure_entry(attr
, span
, target
),
139 sym
::collapse_debuginfo
=> self.check_collapse_debuginfo(attr
, span
, target
),
140 sym
::const_trait
=> self.check_const_trait(attr
, span
, target
),
141 sym
::must_not_suspend
=> self.check_must_not_suspend(&attr
, span
, target
),
142 sym
::must_use
=> self.check_must_use(hir_id
, &attr
, span
, target
),
143 sym
::rustc_pass_by_value
=> self.check_pass_by_value(&attr
, span
, target
),
144 sym
::rustc_allow_incoherent_impl
=> {
145 self.check_allow_incoherent_impl(&attr
, span
, target
)
147 sym
::rustc_has_incoherent_inherent_impls
=> {
148 self.check_has_incoherent_inherent_impls(&attr
, span
, target
)
150 sym
::rustc_const_unstable
151 | sym
::rustc_const_stable
154 | sym
::rustc_allowed_through_unstable_modules
155 | sym
::rustc_promotable
=> self.check_stability_promotable(&attr
, span
, target
),
156 sym
::link_ordinal
=> self.check_link_ordinal(&attr
, span
, target
),
159 is_valid
&= attr_is_valid
;
162 match attr
.name_or_empty() {
163 sym
::cold
=> self.check_cold(hir_id
, attr
, span
, target
),
164 sym
::link
=> self.check_link(hir_id
, attr
, span
, target
),
165 sym
::link_name
=> self.check_link_name(hir_id
, attr
, span
, target
),
166 sym
::link_section
=> self.check_link_section(hir_id
, attr
, span
, target
),
167 sym
::no_mangle
=> self.check_no_mangle(hir_id
, attr
, span
, target
),
168 sym
::deprecated
=> self.check_deprecated(hir_id
, attr
, span
, target
),
169 sym
::macro_use
| sym
::macro_escape
=> self.check_macro_use(hir_id
, attr
, target
),
170 sym
::path
=> self.check_generic_attr(hir_id
, attr
, target
, Target
::Mod
),
171 sym
::plugin_registrar
=> self.check_plugin_registrar(hir_id
, attr
, target
),
172 sym
::macro_export
=> self.check_macro_export(hir_id
, attr
, target
),
173 sym
::ignore
| sym
::should_panic
| sym
::proc_macro_derive
=> {
174 self.check_generic_attr(hir_id
, attr
, target
, Target
::Fn
)
176 sym
::automatically_derived
=> {
177 self.check_generic_attr(hir_id
, attr
, target
, Target
::Impl
)
179 sym
::no_implicit_prelude
=> {
180 self.check_generic_attr(hir_id
, attr
, target
, Target
::Mod
)
182 sym
::rustc_object_lifetime_default
=> self.check_object_lifetime_default(hir_id
),
186 let builtin
= attr
.ident().and_then(|ident
| BUILTIN_ATTRIBUTE_MAP
.get(&ident
.name
));
188 if hir_id
!= CRATE_HIR_ID
{
189 if let Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }
) =
190 attr
.ident().and_then(|ident
| BUILTIN_ATTRIBUTE_MAP
.get(&ident
.name
))
193 ast
::AttrStyle
::Outer
=> self.tcx
.emit_spanned_lint(
197 errors
::OuterCrateLevelAttr
,
199 ast
::AttrStyle
::Inner
=> self.tcx
.emit_spanned_lint(
203 errors
::InnerCrateLevelAttr
,
209 if let Some(BuiltinAttribute { duplicates, .. }
) = builtin
{
210 check_duplicates(self.tcx
, attr
, hir_id
, *duplicates
, &mut seen
);
213 self.check_unused_attribute(hir_id
, attr
)
220 // FIXME(@lcnr): this doesn't belong here.
227 | Target
::ForeignStatic
229 self.tcx
.ensure().codegen_fn_attrs(self.tcx
.hir().local_def_id(hir_id
));
232 self.check_repr(attrs
, span
, target
, item
, hir_id
);
233 self.check_used(attrs
, target
);
236 fn inline_attr_str_error_with_macro_def(&self, hir_id
: HirId
, attr
: &Attribute
, sym
: &str) {
237 self.tcx
.emit_spanned_lint(
241 errors
::IgnoredAttrWithMacro { sym }
,
245 fn inline_attr_str_error_without_macro_def(&self, hir_id
: HirId
, attr
: &Attribute
, sym
: &str) {
246 self.tcx
.emit_spanned_lint(
250 errors
::IgnoredAttr { sym }
,
254 /// Checks if an `#[inline]` is applied to a function or a closure. Returns `true` if valid.
255 fn check_inline(&self, hir_id
: HirId
, attr
: &Attribute
, span
: Span
, target
: Target
) -> bool
{
259 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
260 Target
::Method(MethodKind
::Trait { body: false }
) | Target
::ForeignFn
=> {
261 self.tcx
.emit_spanned_lint(
265 errors
::IgnoredInlineAttrFnProto
,
269 // FIXME(#65833): We permit associated consts to have an `#[inline]` attribute with
270 // just a lint, because we previously erroneously allowed it and some crates used it
271 // accidentally, to be compatible with crates depending on them, we can't throw an
273 Target
::AssocConst
=> {
274 self.tcx
.emit_spanned_lint(
278 errors
::IgnoredInlineAttrConstants
,
282 // FIXME(#80564): Same for fields, arms, and macro defs
283 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
284 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "inline");
288 self.tcx
.sess
.emit_err(errors
::InlineNotFnOrClosure
{
289 attr_span
: attr
.span
,
297 /// Checks if a `#[no_coverage]` is applied directly to a function
298 fn check_no_coverage(
306 // no_coverage on function is fine
309 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
311 // function prototypes can't be covered
312 Target
::Method(MethodKind
::Trait { body: false }
) | Target
::ForeignFn
=> {
313 self.tcx
.emit_spanned_lint(
317 errors
::IgnoredNoCoverageFnProto
,
322 Target
::Mod
| Target
::ForeignMod
| Target
::Impl
| Target
::Trait
=> {
323 self.tcx
.emit_spanned_lint(
327 errors
::IgnoredNoCoveragePropagate
,
332 Target
::Expression
| Target
::Statement
| Target
::Arm
=> {
333 self.tcx
.emit_spanned_lint(
337 errors
::IgnoredNoCoverageFnDefn
,
343 self.tcx
.sess
.emit_err(errors
::IgnoredNoCoverageNotCoverable
{
344 attr_span
: attr
.span
,
352 fn check_generic_attr(
357 allowed_target
: Target
,
359 if target
!= allowed_target
{
360 self.tcx
.emit_spanned_lint(
365 attr_name
: attr
.name_or_empty(),
366 target_name
: allowed_target
.name().replace(" ", "_"),
372 /// Checks if `#[naked]` is applied to a function definition.
373 fn check_naked(&self, hir_id
: HirId
, attr
: &Attribute
, span
: Span
, target
: Target
) -> bool
{
376 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
377 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
378 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
379 // erroneously allowed it and some crates used it accidentally, to be compatible
380 // with crates depending on them, we can't throw an error here.
381 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
382 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "naked");
386 self.tcx
.sess
.emit_err(errors
::AttrShouldBeAppliedToFn
{
387 attr_span
: attr
.span
,
395 /// Checks if `#[cmse_nonsecure_entry]` is applied to a function definition.
396 fn check_cmse_nonsecure_entry(&self, attr
: &Attribute
, span
: Span
, target
: Target
) -> bool
{
399 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
401 self.tcx
.sess
.emit_err(errors
::AttrShouldBeAppliedToFn
{
402 attr_span
: attr
.span
,
410 /// Debugging aid for `object_lifetime_default` query.
411 fn check_object_lifetime_default(&self, hir_id
: HirId
) {
413 if let Some(generics
) = tcx
.hir().get_generics(tcx
.hir().local_def_id(hir_id
)) {
414 for p
in generics
.params
{
415 let hir
::GenericParamKind
::Type { .. }
= p
.kind
else { continue }
;
416 let param_id
= tcx
.hir().local_def_id(p
.hir_id
);
417 let default = tcx
.object_lifetime_default(param_id
);
418 let repr
= match default {
419 ObjectLifetimeDefault
::Empty
=> "BaseDefault".to_owned(),
420 ObjectLifetimeDefault
::Static
=> "'static".to_owned(),
421 ObjectLifetimeDefault
::Param(def_id
) => tcx
.item_name(def_id
).to_string(),
422 ObjectLifetimeDefault
::Ambiguous
=> "Ambiguous".to_owned(),
424 tcx
.sess
.emit_err(ObjectLifetimeErr { span: p.span, repr }
);
429 /// Checks if `#[collapse_debuginfo]` is applied to a macro.
430 fn check_collapse_debuginfo(&self, attr
: &Attribute
, span
: Span
, target
: Target
) -> bool
{
432 Target
::MacroDef
=> true,
436 .emit_err(errors
::CollapseDebuginfo { attr_span: attr.span, defn_span: span }
);
442 /// Checks if a `#[track_caller]` is applied to a non-naked function. Returns `true` if valid.
443 fn check_track_caller(
452 _
if attrs
.iter().any(|attr
| attr
.has_name(sym
::naked
)) => {
453 self.tcx
.sess
.emit_err(errors
::NakedTrackedCaller { attr_span }
);
456 Target
::Fn
| Target
::Method(..) | Target
::ForeignFn
| Target
::Closure
=> true,
457 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
458 // `#[track_caller]` attribute with just a lint, because we previously
459 // erroneously allowed it and some crates used it accidentally, to be compatible
460 // with crates depending on them, we can't throw an error here.
461 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
463 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "track_caller");
470 .emit_err(errors
::TrackedCallerWrongLocation { attr_span, defn_span: span }
);
476 /// Checks if the `#[non_exhaustive]` attribute on an `item` is valid. Returns `true` if valid.
477 fn check_non_exhaustive(
485 Target
::Struct
| Target
::Enum
| Target
::Variant
=> true,
486 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
487 // `#[non_exhaustive]` attribute with just a lint, because we previously
488 // erroneously allowed it and some crates used it accidentally, to be compatible
489 // with crates depending on them, we can't throw an error here.
490 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
491 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "non_exhaustive");
495 self.tcx
.sess
.emit_err(errors
::NonExhaustiveWrongLocation
{
496 attr_span
: attr
.span
,
504 /// Checks if the `#[marker]` attribute on an `item` is valid. Returns `true` if valid.
505 fn check_marker(&self, hir_id
: HirId
, attr
: &Attribute
, span
: Span
, target
: Target
) -> bool
{
507 Target
::Trait
=> true,
508 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
509 // `#[marker]` attribute with just a lint, because we previously
510 // erroneously allowed it and some crates used it accidentally, to be compatible
511 // with crates depending on them, we can't throw an error here.
512 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
513 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "marker");
517 self.tcx
.sess
.emit_err(errors
::AttrShouldBeAppliedToTrait
{
518 attr_span
: attr
.span
,
526 /// Checks if the `#[rustc_must_implement_one_of]` attribute on a `target` is valid. Returns `true` if valid.
527 fn check_rustc_must_implement_one_of(
534 Target
::Trait
=> true,
536 self.tcx
.sess
.emit_err(errors
::AttrShouldBeAppliedToTrait
{
537 attr_span
: attr
.span
,
545 /// Checks if the `#[target_feature]` attribute on `item` is valid. Returns `true` if valid.
546 fn check_target_feature(
555 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
556 // FIXME: #[target_feature] was previously erroneously allowed on statements and some
557 // crates used this, so only emit a warning.
558 Target
::Statement
=> {
559 self.tcx
.emit_spanned_lint(
563 errors
::TargetFeatureOnStatement
,
567 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
568 // `#[target_feature]` attribute with just a lint, because we previously
569 // erroneously allowed it and some crates used it accidentally, to be compatible
570 // with crates depending on them, we can't throw an error here.
571 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
572 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "target_feature");
576 self.tcx
.sess
.emit_err(errors
::AttrShouldBeAppliedToFn
{
577 attr_span
: attr
.span
,
585 /// Checks if the `#[thread_local]` attribute on `item` is valid. Returns `true` if valid.
586 fn check_thread_local(&self, attr
: &Attribute
, span
: Span
, target
: Target
) -> bool
{
588 Target
::ForeignStatic
| Target
::Static
=> true,
590 self.tcx
.sess
.emit_err(errors
::AttrShouldBeAppliedToStatic
{
591 attr_span
: attr
.span
,
599 fn doc_attr_str_error(&self, meta
: &NestedMetaItem
, attr_name
: &str) {
600 self.tcx
.sess
.emit_err(errors
::DocExpectStr { attr_span: meta.span(), attr_name }
);
603 fn check_doc_alias_value(
605 meta
: &NestedMetaItem
,
610 aliases
: &mut FxHashMap
<String
, Span
>,
613 let span
= meta
.name_value_literal_span().unwrap_or_else(|| meta
.span());
615 &format
!("`#[doc(alias{})]`", if is_list { "(\"...\")" }
else { " = \"...\"" }
);
616 if doc_alias
== kw
::Empty
{
617 tcx
.sess
.emit_err(errors
::DocAliasEmpty { span, attr_str }
);
621 let doc_alias_str
= doc_alias
.as_str();
622 if let Some(c
) = doc_alias_str
624 .find(|&c
| c
== '
"' || c == '\'' || (c.is_whitespace() && c != ' '))
626 tcx.sess.emit_err(errors::DocAliasBadChar { span, attr_str, char_: c });
629 if doc_alias_str.starts_with(' ') || doc_alias_str.ends_with(' ') {
630 tcx.sess.emit_err(errors::DocAliasStartEnd { span, attr_str });
634 let span = meta.span();
635 if let Some(location) = match target {
637 let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
638 let containing_item = self.tcx.hir().expect_item(parent_def_id);
639 if Target::from_item(containing_item) == Target::Impl {
640 Some("type alias
in implementation block
")
645 Target::AssocConst => {
646 let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
647 let containing_item = self.tcx.hir().expect_item(parent_def_id);
648 // We can't link to trait impl's consts.
649 let err = "associated constant
in trait implementation block
";
650 match containing_item.kind {
651 ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => Some(err),
655 // we check the validity of params elsewhere
656 Target::Param => return false,
662 | Target::Impl => Some(target.name()),
672 | Target::ImplTraitPlaceholder
682 | Target::ForeignStatic
684 | Target::GenericParam(..)
687 | Target::ExprField => None,
689 tcx.sess.emit_err(errors::DocAliasBadLocation { span, attr_str, location });
692 let item_name = self.tcx.hir().name(hir_id);
693 if item_name == doc_alias {
694 tcx.sess.emit_err(errors::DocAliasNotAnAlias { span, attr_str });
697 if let Err(entry) = aliases.try_insert(doc_alias_str.to_owned(), span) {
698 self.tcx.emit_spanned_lint(
702 errors::DocAliasDuplicated { first_defn: *entry.entry.get() },
710 meta: &NestedMetaItem,
713 aliases: &mut FxHashMap<String, Span>,
715 if let Some(values) = meta.meta_item_list() {
719 Some(l) => match l.kind {
720 LitKind::Str(s, _) => {
721 if !self.check_doc_alias_value(v, s, hir_id, target, true, aliases) {
728 .emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
733 self.tcx.sess.emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
739 } else if let Some(doc_alias) = meta.value_str() {
740 self.check_doc_alias_value(meta, doc_alias, hir_id, target, false, aliases)
742 self.tcx.sess.emit_err(errors::DocAliasMalformed { span: meta.span() });
747 fn check_doc_keyword(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
748 let doc_keyword = meta.value_str().unwrap_or(kw::Empty);
749 if doc_keyword == kw::Empty {
750 self.doc_attr_str_error(meta, "keyword
");
753 match self.tcx.hir().find(hir_id).and_then(|node| match node {
754 hir::Node::Item(item) => Some(&item.kind),
757 Some(ItemKind::Mod(ref module)) => {
758 if !module.item_ids.is_empty() {
759 self.tcx.sess.emit_err(errors::DocKeywordEmptyMod { span: meta.span() });
764 self.tcx.sess.emit_err(errors::DocKeywordNotMod { span: meta.span() });
768 if !rustc_lexer::is_ident(doc_keyword.as_str()) {
769 self.tcx.sess.emit_err(errors::DocKeywordInvalidIdent {
770 span: meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
778 fn check_doc_fake_variadic(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
779 match self.tcx.hir().find(hir_id).and_then(|node| match node {
780 hir::Node::Item(item) => Some(&item.kind),
783 Some(ItemKind::Impl(ref i)) => {
784 let is_valid = matches!(&i.self_ty.kind, hir::TyKind::Tup([_]))
785 || if let hir::TyKind::BareFn(bare_fn_ty) = &i.self_ty.kind {
786 bare_fn_ty.decl.inputs.len() == 1
791 self.tcx.sess.emit_err(errors::DocFakeVariadicNotValid { span: meta.span() });
796 self.tcx.sess.emit_err(errors::DocKeywordOnlyImpl { span: meta.span() });
803 /// Checks `#[doc(inline)]`/`#[doc(no_inline)]` attributes. Returns `true` if valid.
805 /// A doc inlining attribute is invalid if it is applied to a non-`use` item, or
806 /// if there are conflicting attributes for one item.
808 /// `specified_inline` is used to keep track of whether we have
809 /// already seen an inlining attribute for this item.
810 /// If so, `specified_inline` holds the value and the span of
811 /// the first `inline`/`no_inline` attribute.
815 meta: &NestedMetaItem,
818 specified_inline: &mut Option<(bool, Span)>,
820 if target == Target::Use || target == Target::ExternCrate {
821 let do_inline = meta.name_or_empty() == sym::inline;
822 if let Some((prev_inline, prev_span)) = *specified_inline {
823 if do_inline != prev_inline {
824 let mut spans = MultiSpan::from_spans(vec![prev_span, meta.span()]);
825 spans.push_span_label(prev_span, fluent::passes_doc_inline_conflict_first);
826 spans.push_span_label(meta.span(), fluent::passes_doc_inline_conflict_second);
827 self.tcx.sess.emit_err(errors::DocKeywordConflict { spans });
832 *specified_inline = Some((do_inline, meta.span()));
836 self.tcx.emit_spanned_lint(
837 INVALID_DOC_ATTRIBUTES,
840 errors::DocInlineOnlyUse {
841 attr_span: meta.span(),
842 item_span: (attr.style == AttrStyle::Outer)
843 .then(|| self.tcx.hir().span(hir_id)),
850 /// Checks that an attribute is *not* used at the crate level. Returns `true` if valid.
851 fn check_attr_not_crate_level(
853 meta: &NestedMetaItem,
857 if CRATE_HIR_ID == hir_id {
858 self.tcx.sess.emit_err(errors::DocAttrNotCrateLevel { span: meta.span(), attr_name });
864 /// Checks that an attribute is used at the crate level. Returns `true` if valid.
865 fn check_attr_crate_level(
868 meta: &NestedMetaItem,
871 if hir_id != CRATE_HIR_ID {
872 self.tcx.struct_span_lint_hir(
873 INVALID_DOC_ATTRIBUTES,
876 fluent::passes_attr_crate_level,
878 if attr.style == AttrStyle::Outer
879 && self.tcx.hir().get_parent_item(hir_id) == CRATE_OWNER_ID
881 if let Ok(mut src) = self.tcx.sess.source_map().span_to_snippet(attr.span) {
883 err.span_suggestion_verbose(
887 Applicability::MaybeIncorrect,
890 err.span_help(attr.span, fluent::help);
893 err.note(fluent::note);
902 /// Checks that `doc(test(...))` attribute contains only valid attributes. Returns `true` if
904 fn check_test_attr(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
905 let mut is_valid = true;
906 if let Some(metas) = meta.meta_item_list() {
907 for i_meta in metas {
908 match i_meta.name_or_empty() {
909 sym::attr | sym::no_crate_inject => {}
911 self.tcx.emit_spanned_lint(
912 INVALID_DOC_ATTRIBUTES,
915 errors::DocTestUnknown {
916 path: rustc_ast_pretty::pprust::path_to_string(
917 &i_meta.meta_item().unwrap().path,
926 self.tcx.emit_spanned_lint(
927 INVALID_DOC_ATTRIBUTES,
930 errors::DocTestTakesList,
937 /// Check that the `#![doc(cfg_hide(...))]` attribute only contains a list of attributes.
938 /// Returns `true` if valid.
939 fn check_doc_cfg_hide(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
940 if meta.meta_item_list().is_some() {
943 self.tcx.emit_spanned_lint(
944 INVALID_DOC_ATTRIBUTES,
947 errors::DocCfgHideTakesList,
953 /// Runs various checks on `#[doc]` attributes. Returns `true` if valid.
955 /// `specified_inline` should be initialized to `None` and kept for the scope
956 /// of one item. Read the documentation of [`check_doc_inline`] for more information.
958 /// [`check_doc_inline`]: Self::check_doc_inline
964 specified_inline: &mut Option<(bool, Span)>,
965 aliases: &mut FxHashMap<String, Span>,
967 let mut is_valid = true;
969 if let Some(mi) = attr.meta() && let Some(list) = mi.meta_item_list() {
971 if let Some(i_meta) = meta.meta_item() {
972 match i_meta.name_or_empty() {
974 if !self.check_attr_not_crate_level(meta, hir_id, "alias
")
975 || !self.check_doc_alias(meta, hir_id, target, aliases) =>
981 if !self.check_attr_not_crate_level(meta, hir_id, "keyword
")
982 || !self.check_doc_keyword(meta, hir_id) =>
988 if !self.check_attr_not_crate_level(meta, hir_id, "fake_variadic
")
989 || !self.check_doc_fake_variadic(meta, hir_id) =>
994 sym::html_favicon_url
996 | sym::html_playground_url
997 | sym::issue_tracker_base_url
999 | sym::html_no_source
1001 if !self.check_attr_crate_level(attr, meta, hir_id) =>
1007 if !self.check_attr_crate_level(attr, meta, hir_id)
1008 || !self.check_doc_cfg_hide(meta, hir_id) =>
1013 sym::inline | sym::no_inline
1014 if !self.check_doc_inline(
1025 // no_default_passes: deprecated
1026 // passes: deprecated
1027 // plugins: removed, but rustdoc warns about it itself
1032 | sym::html_favicon_url
1033 | sym::html_logo_url
1034 | sym::html_no_source
1035 | sym::html_playground_url
1036 | sym::html_root_url
1038 | sym::issue_tracker_base_url
1041 | sym::no_default_passes
1043 | sym::notable_trait
1046 | sym::fake_variadic => {}
1049 if !self.check_test_attr(meta, hir_id) {
1055 if !self.tcx.features().rustdoc_internals {
1056 self.tcx.emit_spanned_lint(
1057 INVALID_DOC_ATTRIBUTES,
1060 errors::DocPrimitive,
1066 let path = rustc_ast_pretty::pprust::path_to_string(&i_meta.path);
1067 if i_meta.has_name(sym::spotlight) {
1068 self.tcx.emit_spanned_lint(
1069 INVALID_DOC_ATTRIBUTES,
1072 errors::DocTestUnknownSpotlight {
1077 } else if i_meta.has_name(sym::include) &&
1078 let Some(value) = i_meta.value_str() {
1079 let applicability = if list.len() == 1 {
1080 Applicability::MachineApplicable
1082 Applicability::MaybeIncorrect
1084 // If there are multiple attributes, the suggestion would suggest
1085 // deleting all of them, which is incorrect.
1086 self.tcx.emit_spanned_lint(
1087 INVALID_DOC_ATTRIBUTES,
1090 errors::DocTestUnknownInclude {
1092 value: value.to_string(),
1093 inner: (attr.style == AttrStyle::Inner)
1096 sugg: (attr.meta().unwrap().span, applicability),
1100 self.tcx.emit_spanned_lint(
1101 INVALID_DOC_ATTRIBUTES,
1104 errors::DocTestUnknownAny { path }
1111 self.tcx.emit_spanned_lint(
1112 INVALID_DOC_ATTRIBUTES,
1125 /// Warns against some misuses of `#[pass_by_value]`
1126 fn check_pass_by_value(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1128 Target::Struct | Target::Enum | Target::TyAlias => true,
1130 self.tcx.sess.emit_err(errors::PassByValue { attr_span: attr.span, span });
1136 fn check_allow_incoherent_impl(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1138 Target::Method(MethodKind::Inherent) => true,
1140 self.tcx.sess.emit_err(errors::AllowIncoherentImpl { attr_span: attr.span, span });
1146 fn check_has_incoherent_inherent_impls(
1153 Target::Trait | Target::Struct | Target::Enum | Target::Union | Target::ForeignTy => {
1159 .emit_err(errors::HasIncoherentInherentImpl { attr_span: attr.span, span });
1165 /// Warns against some misuses of `#[must_use]`
1166 fn check_must_use(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
1167 let node = self.tcx.hir().get(hir_id);
1168 if let Some(kind) = node.fn_kind() && let rustc_hir::IsAsync::Async = kind.asyncness() {
1169 self.tcx.emit_spanned_lint(
1173 errors::MustUseAsync { span }
1185 // `impl Trait` in return position can trip
1186 // `unused_must_use` if `Trait` is marked as
1190 let article = match target {
1195 | Target::Expression
1197 | Target::AssocConst
1198 | Target::AssocTy => "an
",
1202 self.tcx.emit_spanned_lint(
1206 errors::MustUseNoEffect { article, target },
1210 // For now, its always valid
1214 /// Checks if `#[must_not_suspend]` is applied to a function. Returns `true` if valid.
1215 fn check_must_not_suspend(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1217 Target::Struct | Target::Enum | Target::Union | Target::Trait => true,
1219 self.tcx.sess.emit_err(errors::MustNotSuspend { attr_span: attr.span, span });
1225 /// Checks if `#[cold]` is applied to a non-function. Returns `true` if valid.
1226 fn check_cold(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1228 Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => {}
1229 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1230 // `#[cold]` attribute with just a lint, because we previously
1231 // erroneously allowed it and some crates used it accidentally, to be compatible
1232 // with crates depending on them, we can't throw an error here.
1233 Target::Field | Target::Arm | Target::MacroDef => {
1234 self.inline_attr_str_error_with_macro_def(hir_id, attr, "cold
");
1237 // FIXME: #[cold] was previously allowed on non-functions and some crates used
1238 // this, so only emit a warning.
1239 self.tcx.emit_spanned_lint(
1243 errors::Cold { span },
1249 /// Checks if `#[link]` is applied to an item other than a foreign module.
1250 fn check_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1251 if target == Target::ForeignMod
1252 && let hir::Node::Item(item) = self.tcx.hir().get(hir_id)
1253 && let Item { kind: ItemKind::ForeignMod { abi, .. }, .. } = item
1254 && !matches!(abi, Abi::Rust | Abi::RustIntrinsic | Abi::PlatformIntrinsic)
1259 self.tcx.emit_spanned_lint(
1263 errors::Link { span: (target != Target::ForeignMod).then_some(span) },
1267 /// Checks if `#[link_name]` is applied to an item other than a foreign function or static.
1268 fn check_link_name(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1270 Target::ForeignFn | Target::ForeignStatic => {}
1271 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1272 // `#[link_name]` attribute with just a lint, because we previously
1273 // erroneously allowed it and some crates used it accidentally, to be compatible
1274 // with crates depending on them, we can't throw an error here.
1275 Target::Field | Target::Arm | Target::MacroDef => {
1276 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_name
");
1279 // FIXME: #[cold] was previously allowed on non-functions/statics and some crates
1280 // used this, so only emit a warning.
1281 let attr_span = matches!(target, Target::ForeignMod).then_some(attr.span);
1282 if let Some(s) = attr.value_str() {
1283 self.tcx.emit_spanned_lint(
1287 errors::LinkName { span, attr_span, value: s.as_str() },
1290 self.tcx.emit_spanned_lint(
1294 errors::LinkName { span, attr_span, value: "..." },
1301 /// Checks if `#[no_link]` is applied to an `extern crate`. Returns `true` if valid.
1302 fn check_no_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
1304 Target::ExternCrate => true,
1305 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1306 // `#[no_link]` attribute with just a lint, because we previously
1307 // erroneously allowed it and some crates used it accidentally, to be compatible
1308 // with crates depending on them, we can't throw an error here.
1309 Target::Field | Target::Arm | Target::MacroDef => {
1310 self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_link
");
1314 self.tcx.sess.emit_err(errors::NoLink { attr_span: attr.span, span });
1320 fn is_impl_item(&self, hir_id: HirId) -> bool {
1321 matches!(self.tcx.hir().get(hir_id), hir::Node::ImplItem(..))
1324 /// Checks if `#[export_name]` is applied to a function or static. Returns `true` if valid.
1325 fn check_export_name(
1333 Target::Static | Target::Fn => true,
1334 Target::Method(..) if self.is_impl_item(hir_id) => true,
1335 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1336 // `#[export_name]` attribute with just a lint, because we previously
1337 // erroneously allowed it and some crates used it accidentally, to be compatible
1338 // with crates depending on them, we can't throw an error here.
1339 Target::Field | Target::Arm | Target::MacroDef => {
1340 self.inline_attr_str_error_with_macro_def(hir_id, attr, "export_name
");
1344 self.tcx.sess.emit_err(errors::ExportName { attr_span: attr.span, span });
1350 fn check_rustc_layout_scalar_valid_range(
1356 if target != Target::Struct {
1357 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeNotStruct {
1358 attr_span: attr.span,
1364 let Some(list) = attr.meta_item_list() else {
1368 if matches!(&list[..], &[NestedMetaItem::Literal(Lit { kind: LitKind::Int(..), .. })]) {
1371 self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeArg { attr_span: attr.span });
1376 /// Checks if `#[rustc_legacy_const_generics]` is applied to a function and has a valid argument.
1377 fn check_rustc_legacy_const_generics(
1382 item: Option<ItemLike<'_>>,
1384 let is_function = matches!(target, Target::Fn);
1386 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1387 attr_span: attr.span,
1393 let Some(list) = attr.meta_item_list() else {
1394 // The attribute form is validated on AST.
1398 let Some(ItemLike::Item(Item {
1399 kind: ItemKind::Fn(FnSig { decl, .. }, generics, _),
1402 bug!("should be a function item
");
1405 for param in generics.params {
1407 hir::GenericParamKind::Const { .. } => {}
1409 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsOnly {
1410 attr_span: attr.span,
1411 param_span: param.span,
1418 if list.len() != generics.params.len() {
1419 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndex {
1420 attr_span: attr.span,
1421 generics_span: generics.span,
1426 let arg_count = decl.inputs.len() as u128 + generics.params.len() as u128;
1427 let mut invalid_args = vec![];
1429 if let Some(LitKind::Int(val, _)) = meta.literal().map(|lit| &lit.kind) {
1430 if *val >= arg_count {
1431 let span = meta.span();
1432 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexExceed {
1434 arg_count: arg_count as usize,
1439 invalid_args.push(meta.span());
1443 if !invalid_args.is_empty() {
1444 self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexNegative { invalid_args });
1451 /// Helper function for checking that the provided attribute is only applied to a function or
1453 fn check_applied_to_fn_or_method(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1454 let is_function = matches!(target, Target::Fn | Target::Method(..));
1456 self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
1457 attr_span: attr.span,
1466 /// Checks that the `#[rustc_lint_query_instability]` attribute is only applied to a function
1468 fn check_rustc_lint_query_instability(
1474 self.check_applied_to_fn_or_method(attr, span, target)
1477 /// Checks that the `#[rustc_lint_diagnostics]` attribute is only applied to a function or
1479 fn check_rustc_lint_diagnostics(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1480 self.check_applied_to_fn_or_method(attr, span, target)
1483 /// Checks that the `#[rustc_lint_opt_ty]` attribute is only applied to a struct.
1484 fn check_rustc_lint_opt_ty(&self, attr: &Attribute, span: Span, target: Target) -> bool {
1486 Target::Struct => true,
1488 self.tcx.sess.emit_err(errors::RustcLintOptTy { attr_span: attr.span, span });
1494 /// Checks that the `#[rustc_lint_opt_deny_field_access]` attribute is only applied to a field.
1495 fn check_rustc_lint_opt_deny_field_access(
1502 Target::Field => true,
1506 .emit_err(errors::RustcLintOptDenyFieldAccess { attr_span: attr.span, span });
1512 /// Checks that the dep-graph debugging attributes are only present when the query-dep-graph
1513 /// option is passed to the compiler.
1514 fn check_rustc_dirty_clean(&self, attr: &Attribute) -> bool {
1515 if self.tcx.sess.opts.unstable_opts.query_dep_graph {
1518 self.tcx.sess.emit_err(errors::RustcDirtyClean { span: attr.span });
1523 /// Checks if `#[link_section]` is applied to a function or static.
1524 fn check_link_section(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1526 Target::Static | Target::Fn | Target::Method(..) => {}
1527 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1528 // `#[link_section]` attribute with just a lint, because we previously
1529 // erroneously allowed it and some crates used it accidentally, to be compatible
1530 // with crates depending on them, we can't throw an error here.
1531 Target::Field | Target::Arm | Target::MacroDef => {
1532 self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_section
");
1535 // FIXME: #[link_section] was previously allowed on non-functions/statics and some
1536 // crates used this, so only emit a warning.
1537 self.tcx.emit_spanned_lint(
1541 errors::LinkSection { span },
1547 /// Checks if `#[no_mangle]` is applied to a function or static.
1548 fn check_no_mangle(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
1550 Target::Static | Target::Fn => {}
1551 Target::Method(..) if self.is_impl_item(hir_id) => {}
1552 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1553 // `#[no_mangle]` attribute with just a lint, because we previously
1554 // erroneously allowed it and some crates used it accidentally, to be compatible
1555 // with crates depending on them, we can't throw an error here.
1556 Target::Field | Target::Arm | Target::MacroDef => {
1557 self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_mangle
");
1559 // FIXME: #[no_mangle] was previously allowed on non-functions/statics, this should be an error
1560 // The error should specify that the item that is wrong is specifically a *foreign* fn/static
1561 // otherwise the error seems odd
1562 Target::ForeignFn | Target::ForeignStatic => {
1563 let foreign_item_kind = match target {
1564 Target::ForeignFn => "function
",
1565 Target::ForeignStatic => "static",
1566 _ => unreachable!(),
1568 self.tcx.emit_spanned_lint(
1572 errors::NoMangleForeign { span, attr_span: attr.span, foreign_item_kind },
1576 // FIXME: #[no_mangle] was previously allowed on non-functions/statics and some
1577 // crates used this, so only emit a warning.
1578 self.tcx.emit_spanned_lint(
1582 errors::NoMangle { span },
1588 /// Checks if the `#[repr]` attributes on `item` are valid.
1591 attrs: &[Attribute],
1594 item: Option<ItemLike<'_>>,
1597 // Extract the names of all repr hints, e.g., [foo, bar, align] for:
1600 // #[repr(bar, align(8))]
1602 let hints: Vec<_> = attrs
1604 .filter(|attr| attr.has_name(sym::repr))
1605 .filter_map(|attr| attr.meta_item_list())
1609 let mut int_reprs = 0;
1610 let mut is_c = false;
1611 let mut is_simd = false;
1612 let mut is_transparent = false;
1614 for hint in &hints {
1615 if !hint.is_meta_item() {
1616 self.tcx.sess.emit_err(errors::ReprIdent { span: hint.span() });
1620 match hint.name_or_empty() {
1624 Target::Struct | Target::Union | Target::Enum => continue,
1626 self.tcx.sess.emit_err(AttrApplication::StructEnumUnion {
1627 hint_span: hint.span(),
1634 if let (Target::Fn, false) = (target, self.tcx.features().fn_align) {
1636 &self.tcx.sess.parse_sess,
1639 "`
repr(align
)` attributes on functions are unstable
",
1645 Target::Struct | Target::Union | Target::Enum | Target::Fn => continue,
1647 self.tcx.sess.emit_err(AttrApplication::StructEnumFunctionUnion {
1648 hint_span: hint.span(),
1655 if target != Target::Struct && target != Target::Union {
1656 self.tcx.sess.emit_err(AttrApplication::StructUnion {
1657 hint_span: hint.span(),
1666 if target != Target::Struct {
1669 .emit_err(AttrApplication::Struct { hint_span: hint.span(), span });
1674 sym::transparent => {
1675 is_transparent = true;
1677 Target::Struct | Target::Union | Target::Enum => continue,
1679 self.tcx.sess.emit_err(AttrApplication::StructEnumUnion {
1680 hint_span: hint.span(),
1699 if target != Target::Enum {
1702 .emit_err(AttrApplication::Enum { hint_span: hint.span(), span });
1708 self.tcx.sess.emit_err(UnrecognizedReprHint { span: hint.span() });
1714 // Just point at all repr hints if there are any incompatibilities.
1715 // This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
1716 let hint_spans = hints.iter().map(|hint| hint.span());
1718 // Error on repr(transparent, <anything else>).
1719 if is_transparent && hints.len() > 1 {
1720 let hint_spans: Vec<_> = hint_spans.clone().collect();
1723 .emit_err(TransparentIncompatible { hint_spans, target: target.to_string() });
1725 // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
1727 || (is_simd && is_c)
1730 && item.map_or(false, |item| {
1731 if let ItemLike::Item(item) = item {
1732 return is_c_like_enum(item);
1737 self.tcx.emit_spanned_lint(
1738 CONFLICTING_REPR_HINTS,
1740 hint_spans.collect::<Vec<Span>>(),
1741 errors::ReprConflicting,
1746 fn check_used(&self, attrs: &[Attribute], target: Target) {
1747 let mut used_linker_span = None;
1748 let mut used_compiler_span = None;
1749 for attr in attrs.iter().filter(|attr| attr.has_name(sym::used)) {
1750 if target != Target::Static {
1751 self.tcx.sess.emit_err(errors::UsedStatic { span: attr.span });
1753 let inner = attr.meta_item_list();
1754 match inner.as_deref() {
1755 Some([item]) if item.has_name(sym::linker) => {
1756 if used_linker_span.is_none() {
1757 used_linker_span = Some(attr.span);
1760 Some([item]) if item.has_name(sym::compiler) => {
1761 if used_compiler_span.is_none() {
1762 used_compiler_span = Some(attr.span);
1766 // This error case is handled in rustc_hir_analysis::collect.
1769 // Default case (compiler) when arg isn't defined.
1770 if used_compiler_span.is_none() {
1771 used_compiler_span = Some(attr.span);
1776 if let (Some(linker_span), Some(compiler_span)) = (used_linker_span, used_compiler_span) {
1779 .emit_err(errors::UsedCompilerLinker { spans: vec![linker_span, compiler_span] });
1783 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1784 /// (Allows proc_macro functions)
1785 fn check_allow_internal_unstable(
1791 attrs: &[Attribute],
1793 debug!("Checking target
: {:?}
", target);
1797 if self.tcx.sess.is_proc_macro_attr(attr) {
1798 debug!("Is proc
macro attr
");
1802 debug!("Is not proc
macro attr
");
1805 Target::MacroDef => true,
1806 // FIXME(#80564): We permit struct fields and match arms to have an
1807 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1808 // erroneously allowed it and some crates used it accidentally, to be compatible
1809 // with crates depending on them, we can't throw an error here.
1810 Target::Field | Target::Arm => {
1811 self.inline_attr_str_error_without_macro_def(
1814 "allow_internal_unstable
",
1821 .emit_err(errors::AllowInternalUnstable { attr_span: attr.span, span });
1827 /// Checks if the items on the `#[debugger_visualizer]` attribute are valid.
1828 fn check_debugger_visualizer(&self, attr: &Attribute, target: Target) -> bool {
1832 self.tcx.sess.emit_err(errors::DebugVisualizerPlacement { span: attr.span });
1837 let Some(hints) = attr.meta_item_list() else {
1838 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1842 let hint = match hints.len() {
1845 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1850 let Some(meta_item) = hint.meta_item() else {
1851 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
1855 let visualizer_path = match (meta_item.name_or_empty(), meta_item.value_str()) {
1856 (sym::natvis_file, Some(value)) => value,
1857 (sym::gdb_script_file, Some(value)) => value,
1859 self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: meta_item.span });
1865 match resolve_path(&self.tcx.sess.parse_sess, visualizer_path.as_str(), attr.span) {
1873 match std::fs::File::open(&file) {
1876 self.tcx.sess.emit_err(DebugVisualizerUnreadable {
1877 span: meta_item.span,
1886 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1887 /// (Allows proc_macro functions)
1888 fn check_rustc_allow_const_fn_unstable(
1896 Target::Fn | Target::Method(_)
1897 if self.tcx.is_const_fn_raw(self.tcx.hir().local_def_id(hir_id).to_def_id()) =>
1901 // FIXME(#80564): We permit struct fields and match arms to have an
1902 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1903 // erroneously allowed it and some crates used it accidentally, to be compatible
1904 // with crates depending on them, we can't throw an error here.
1905 Target::Field | Target::Arm | Target::MacroDef => {
1906 self.inline_attr_str_error_with_macro_def(hir_id, attr, "allow_internal_unstable
");
1912 .emit_err(errors::RustcAllowConstFnUnstable { attr_span: attr.span, span });
1918 fn check_rustc_std_internal_symbol(
1925 Target::Fn | Target::Static => true,
1929 .emit_err(errors::RustcStdInternalSymbol { attr_span: attr.span, span });
1935 /// `#[const_trait]` only applies to traits.
1936 fn check_const_trait(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1938 Target::Trait => true,
1940 self.tcx.sess.emit_err(errors::ConstTrait { attr_span: attr.span });
1946 fn check_stability_promotable(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1948 Target::Expression => {
1949 self.tcx.sess.emit_err(errors::StabilityPromotable { attr_span: attr.span });
1956 fn check_link_ordinal(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
1958 Target::ForeignFn | Target::ForeignStatic => true,
1960 self.tcx.sess.emit_err(errors::LinkOrdinal { attr_span: attr.span });
1966 fn check_deprecated(&self, hir_id: HirId, attr: &Attribute, _span: Span, target: Target) {
1968 Target::Closure | Target::Expression | Target::Statement | Target::Arm => {
1969 self.tcx.emit_spanned_lint(
1980 fn check_macro_use(&self, hir_id: HirId, attr: &Attribute, target: Target) {
1981 let name = attr.name_or_empty();
1983 Target::ExternCrate | Target::Mod => {}
1985 self.tcx.emit_spanned_lint(
1989 errors::MacroUse { name },
1995 fn check_macro_export(&self, hir_id: HirId, attr: &Attribute, target: Target) {
1996 if target != Target::MacroDef {
1997 self.tcx.emit_spanned_lint(UNUSED_ATTRIBUTES, hir_id, attr.span, errors::MacroExport);
2001 fn check_plugin_registrar(&self, hir_id: HirId, attr: &Attribute, target: Target) {
2002 if target != Target::Fn {
2003 self.tcx.emit_spanned_lint(
2007 errors::PluginRegistrar,
2012 fn check_unused_attribute(&self, hir_id: HirId, attr: &Attribute) {
2013 // Warn on useless empty attributes.
2014 let note = if matches!(
2015 attr.name_or_empty(),
2024 | sym::target_feature
2025 ) && attr.meta_item_list().map_or(false, |list| list.is_empty())
2027 errors::UnusedNote::EmptyList { name: attr.name_or_empty() }
2029 attr.name_or_empty(),
2030 sym::allow | sym::warn | sym::deny | sym::forbid | sym::expect
2031 ) && let Some(meta) = attr.meta_item_list()
2033 && let Some(item) = meta[0].meta_item()
2034 && let MetaItemKind::NameValue(_) = &item.kind
2035 && item.path == sym::reason
2037 errors::UnusedNote::NoLints { name: attr.name_or_empty() }
2038 } else if attr.name_or_empty() == sym::default_method_body_is_const {
2039 errors::UnusedNote::DefaultMethodBodyConst
2044 self.tcx.emit_spanned_lint(
2048 errors::Unused { attr_span: attr.span, note },
2053 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {
2054 type NestedFilter = nested_filter::OnlyBodies;
2056 fn nested_visit_map(&mut self) -> Self::Map {
2060 fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
2061 // Historically we've run more checks on non-exported than exported macros,
2062 // so this lets us continue to run them while maintaining backwards compatibility.
2063 // In the long run, the checks should be harmonized.
2064 if let ItemKind::Macro(ref macro_def, _) = item.kind {
2065 let def_id = item.owner_id.to_def_id();
2066 if macro_def.macro_rules && !self.tcx.has_attr(def_id, sym::macro_export) {
2067 check_non_exported_macro_for_invalid_attrs(self.tcx, item);
2071 let target = Target::from_item(item);
2072 self.check_attributes(item.hir_id(), item.span, target, Some(ItemLike::Item(item)));
2073 intravisit::walk_item(self, item)
2076 fn visit_generic_param(&mut self, generic_param: &'tcx hir::GenericParam<'tcx>) {
2077 let target = Target::from_generic_param(generic_param);
2078 self.check_attributes(generic_param.hir_id, generic_param.span, target, None);
2079 intravisit::walk_generic_param(self, generic_param)
2082 fn visit_trait_item(&mut self, trait_item: &'tcx TraitItem<'tcx>) {
2083 let target = Target::from_trait_item(trait_item);
2084 self.check_attributes(trait_item.hir_id(), trait_item.span, target, None);
2085 intravisit::walk_trait_item(self, trait_item)
2088 fn visit_field_def(&mut self, struct_field: &'tcx hir::FieldDef<'tcx>) {
2089 self.check_attributes(struct_field.hir_id, struct_field.span, Target::Field, None);
2090 intravisit::walk_field_def(self, struct_field);
2093 fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
2094 self.check_attributes(arm.hir_id, arm.span, Target::Arm, None);
2095 intravisit::walk_arm(self, arm);
2098 fn visit_foreign_item(&mut self, f_item: &'tcx ForeignItem<'tcx>) {
2099 let target = Target::from_foreign_item(f_item);
2100 self.check_attributes(f_item.hir_id(), f_item.span, target, Some(ItemLike::ForeignItem));
2101 intravisit::walk_foreign_item(self, f_item)
2104 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
2105 let target = target_from_impl_item(self.tcx, impl_item);
2106 self.check_attributes(impl_item.hir_id(), impl_item.span, target, None);
2107 intravisit::walk_impl_item(self, impl_item)
2110 fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt<'tcx>) {
2111 // When checking statements ignore expressions, they will be checked later.
2112 if let hir::StmtKind::Local(ref l) = stmt.kind {
2113 self.check_attributes(l.hir_id, stmt.span, Target::Statement, None);
2115 intravisit::walk_stmt(self, stmt)
2118 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
2119 let target = match expr.kind {
2120 hir::ExprKind::Closure { .. } => Target::Closure,
2121 _ => Target::Expression,
2124 self.check_attributes(expr.hir_id, expr.span, target, None);
2125 intravisit::walk_expr(self, expr)
2128 fn visit_expr_field(&mut self, field: &'tcx hir::ExprField<'tcx>) {
2129 self.check_attributes(field.hir_id, field.span, Target::ExprField, None);
2130 intravisit::walk_expr_field(self, field)
2133 fn visit_variant(&mut self, variant: &'tcx hir::Variant<'tcx>) {
2134 self.check_attributes(variant.id, variant.span, Target::Variant, None);
2135 intravisit::walk_variant(self, variant)
2138 fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {
2139 self.check_attributes(param.hir_id, param.span, Target::Param, None);
2141 intravisit::walk_param(self, param);
2144 fn visit_pat_field(&mut self, field: &'tcx hir::PatField<'tcx>) {
2145 self.check_attributes(field.hir_id, field.span, Target::PatField, None);
2146 intravisit::walk_pat_field(self, field);
2150 fn is_c_like_enum(item: &Item<'_>) -> bool {
2151 if let ItemKind::Enum(ref def, _) = item.kind {
2152 for variant in def.variants {
2153 match variant.data {
2154 hir::VariantData::Unit(..) => { /* continue */ }
2164 // FIXME: Fix "Cannot determine resolution
" error and remove built-in macros
2166 fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
2167 // Check for builtin attributes at the crate level
2168 // which were unsuccessfully resolved due to cannot determine
2169 // resolution for the attribute macro error.
2170 const ATTRS_TO_CHECK: &[Symbol] = &[
2174 sym::automatically_derived,
2181 sym::global_allocator,
2186 // This function should only be called with crate attributes
2187 // which are inner attributes always but lets check to make sure
2188 if attr.style == AttrStyle::Inner {
2189 for attr_to_check in ATTRS_TO_CHECK {
2190 if attr.has_name(*attr_to_check) {
2191 tcx.sess.emit_err(InvalidAttrAtCrateLevel {
2193 snippet: tcx.sess.source_map().span_to_snippet(attr.span).ok(),
2194 name: *attr_to_check,
2202 fn check_non_exported_macro_for_invalid_attrs(tcx: TyCtxt<'_>, item: &Item<'_>) {
2203 let attrs = tcx.hir().attrs(item.hir_id());
2206 if attr.has_name(sym::inline) {
2207 tcx.sess.emit_err(errors::NonExportedMacroInvalidAttrs { attr_span: attr.span });
2212 fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
2213 let check_attr_visitor = &mut CheckAttrVisitor { tcx };
2214 tcx.hir().visit_item_likes_in_module(module_def_id, check_attr_visitor);
2215 if module_def_id.is_top_level_module() {
2216 check_attr_visitor.check_attributes(CRATE_HIR_ID, DUMMY_SP, Target::Mod, None);
2217 check_invalid_crate_level_attr(tcx, tcx.hir().krate_attrs());
2221 pub(crate) fn provide(providers: &mut Providers) {
2222 *providers = Providers { check_mod_attrs, ..*providers };
2225 fn check_duplicates(
2229 duplicates: AttributeDuplicates,
2230 seen: &mut FxHashMap<Symbol, Span>,
2232 use AttributeDuplicates::*;
2233 if matches!(duplicates, WarnFollowingWordOnly) && !attr.is_word() {
2238 WarnFollowing | FutureWarnFollowing | WarnFollowingWordOnly | FutureWarnPreceding => {
2239 match seen.entry(attr.name_or_empty()) {
2240 Entry::Occupied(mut entry) => {
2241 let (this, other) = if matches!(duplicates, FutureWarnPreceding) {
2242 let to_remove = entry.insert(attr.span);
2243 (to_remove, attr.span)
2245 (attr.span, *entry.get())
2247 tcx.emit_spanned_lint(
2251 errors::UnusedDuplicate {
2256 FutureWarnFollowing | FutureWarnPreceding
2262 Entry::Vacant(entry) => {
2263 entry.insert(attr.span);
2267 ErrorFollowing | ErrorPreceding => match seen.entry(attr.name_or_empty()) {
2268 Entry::Occupied(mut entry) => {
2269 let (this, other) = if matches!(duplicates, ErrorPreceding) {
2270 let to_remove = entry.insert(attr.span);
2271 (to_remove, attr.span)
2273 (attr.span, *entry.get())
2275 tcx.sess.emit_err(errors::UnusedMultiple {
2278 name: attr.name_or_empty(),
2281 Entry::Vacant(entry) => {
2282 entry.insert(attr.span);