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
7 use rustc_middle
::hir
::map
::Map
;
8 use rustc_middle
::ty
::query
::Providers
;
9 use rustc_middle
::ty
::TyCtxt
;
11 use rustc_ast
::{ast, AttrStyle, Attribute, Lit, LitKind, NestedMetaItem}
;
12 use rustc_data_structures
::fx
::{FxHashMap, FxHashSet}
;
13 use rustc_errors
::{pluralize, struct_span_err, Applicability}
;
14 use rustc_feature
::{AttributeType, BUILTIN_ATTRIBUTE_MAP}
;
16 use rustc_hir
::def_id
::LocalDefId
;
17 use rustc_hir
::intravisit
::{self, NestedVisitorMap, Visitor}
;
18 use rustc_hir
::{self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID}
;
19 use rustc_hir
::{MethodKind, Target}
;
20 use rustc_session
::lint
::builtin
::{
21 CONFLICTING_REPR_HINTS
, INVALID_DOC_ATTRIBUTES
, UNUSED_ATTRIBUTES
,
23 use rustc_session
::parse
::feature_err
;
24 use rustc_span
::symbol
::{sym, Symbol}
;
25 use rustc_span
::{MultiSpan, Span, DUMMY_SP}
;
27 pub(crate) fn target_from_impl_item
<'tcx
>(
29 impl_item
: &hir
::ImplItem
<'_
>,
31 match impl_item
.kind
{
32 hir
::ImplItemKind
::Const(..) => Target
::AssocConst
,
33 hir
::ImplItemKind
::Fn(..) => {
34 let parent_hir_id
= tcx
.hir().get_parent_item(impl_item
.hir_id());
35 let containing_item
= tcx
.hir().expect_item(parent_hir_id
);
36 let containing_impl_is_for_trait
= match &containing_item
.kind
{
37 hir
::ItemKind
::Impl(impl_
) => impl_
.of_trait
.is_some(),
38 _
=> bug
!("parent of an ImplItem must be an Impl"),
40 if containing_impl_is_for_trait
{
41 Target
::Method(MethodKind
::Trait { body: true }
)
43 Target
::Method(MethodKind
::Inherent
)
46 hir
::ImplItemKind
::TyAlias(..) => Target
::AssocTy
,
50 #[derive(Clone, Copy)]
52 Item(&'tcx Item
<'tcx
>),
53 ForeignItem(&'tcx ForeignItem
<'tcx
>),
56 struct CheckAttrVisitor
<'tcx
> {
60 impl CheckAttrVisitor
<'tcx
> {
61 /// Checks any attribute.
67 item
: Option
<ItemLike
<'_
>>,
69 let mut doc_aliases
= FxHashMap
::default();
70 let mut is_valid
= true;
71 let mut specified_inline
= None
;
72 let mut seen
= FxHashSet
::default();
73 let attrs
= self.tcx
.hir().attrs(hir_id
);
75 let attr_is_valid
= match attr
.name_or_empty() {
76 sym
::inline
=> self.check_inline(hir_id
, attr
, span
, target
),
77 sym
::non_exhaustive
=> self.check_non_exhaustive(hir_id
, attr
, span
, target
),
78 sym
::marker
=> self.check_marker(hir_id
, attr
, span
, target
),
79 sym
::target_feature
=> self.check_target_feature(hir_id
, attr
, span
, target
),
80 sym
::track_caller
=> {
81 self.check_track_caller(hir_id
, &attr
.span
, attrs
, span
, target
)
83 sym
::doc
=> self.check_doc_attrs(
87 &mut specified_inline
,
90 sym
::no_link
=> self.check_no_link(hir_id
, &attr
, span
, target
),
91 sym
::export_name
=> self.check_export_name(hir_id
, &attr
, span
, target
),
92 sym
::rustc_layout_scalar_valid_range_start
93 | sym
::rustc_layout_scalar_valid_range_end
=> {
94 self.check_rustc_layout_scalar_valid_range(&attr
, span
, target
)
96 sym
::allow_internal_unstable
=> {
97 self.check_allow_internal_unstable(hir_id
, &attr
, span
, target
, &attrs
)
99 sym
::rustc_allow_const_fn_unstable
=> {
100 self.check_rustc_allow_const_fn_unstable(hir_id
, &attr
, span
, target
)
102 sym
::naked
=> self.check_naked(hir_id
, attr
, span
, target
),
103 sym
::rustc_legacy_const_generics
=> {
104 self.check_rustc_legacy_const_generics(&attr
, span
, target
, item
)
108 | sym
::rustc_if_this_changed
109 | sym
::rustc_then_this_would_need
=> self.check_rustc_dirty_clean(&attr
),
110 sym
::cmse_nonsecure_entry
=> self.check_cmse_nonsecure_entry(attr
, span
, target
),
111 sym
::default_method_body_is_const
=> {
112 self.check_default_method_body_is_const(attr
, span
, target
)
114 sym
::must_not_suspend
=> self.check_must_not_suspend(&attr
, span
, target
),
115 sym
::rustc_const_unstable
116 | sym
::rustc_const_stable
119 | sym
::rustc_promotable
=> self.check_stability_promotable(&attr
, span
, target
),
122 is_valid
&= attr_is_valid
;
125 match attr
.name_or_empty() {
126 sym
::cold
=> self.check_cold(hir_id
, attr
, span
, target
),
127 sym
::link_name
=> self.check_link_name(hir_id
, attr
, span
, target
),
128 sym
::link_section
=> self.check_link_section(hir_id
, attr
, span
, target
),
129 sym
::no_mangle
=> self.check_no_mangle(hir_id
, attr
, span
, target
),
130 sym
::deprecated
| sym
::rustc_deprecated
=> {
131 self.check_deprecated(hir_id
, attr
, span
, target
)
133 sym
::macro_use
| sym
::macro_escape
=> self.check_macro_use(hir_id
, attr
, target
),
134 sym
::path
=> self.check_generic_attr(hir_id
, attr
, target
, &[Target
::Mod
]),
135 sym
::cfg_attr
=> self.check_cfg_attr(hir_id
, attr
),
136 sym
::plugin_registrar
=> self.check_plugin_registrar(hir_id
, attr
, target
),
137 sym
::macro_export
=> self.check_macro_export(hir_id
, attr
, target
),
138 sym
::ignore
| sym
::should_panic
| sym
::proc_macro_derive
=> {
139 self.check_generic_attr(hir_id
, attr
, target
, &[Target
::Fn
])
141 sym
::automatically_derived
=> {
142 self.check_generic_attr(hir_id
, attr
, target
, &[Target
::Impl
])
144 sym
::no_implicit_prelude
=> {
145 self.check_generic_attr(hir_id
, attr
, target
, &[Target
::Mod
])
150 if hir_id
!= CRATE_HIR_ID
{
151 if let Some((_
, AttributeType
::CrateLevel
, ..)) =
152 attr
.ident().and_then(|ident
| BUILTIN_ATTRIBUTE_MAP
.get(&ident
.name
))
154 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
155 let msg
= match attr
.style
{
156 ast
::AttrStyle
::Outer
=> {
157 "crate-level attribute should be an inner attribute: add an exclamation \
160 ast
::AttrStyle
::Inner
=> "crate-level attribute should be in the root module",
162 lint
.build(msg
).emit()
167 // Duplicate attributes
168 match attr
.name_or_empty() {
169 name @ sym
::macro_use
=> {
170 let args
= attr
.meta_item_list().unwrap_or_else(Vec
::new
);
171 let args
: Vec
<_
> = args
.iter().map(|arg
| arg
.name_or_empty()).collect();
172 if !seen
.insert((name
, args
)) {
173 self.tcx
.struct_span_lint_hir(
177 |lint
| lint
.build("unused attribute").emit(),
189 if matches
!(target
, Target
::Closure
| Target
::Fn
| Target
::Method(_
) | Target
::ForeignFn
) {
190 self.tcx
.ensure().codegen_fn_attrs(self.tcx
.hir().local_def_id(hir_id
));
193 self.check_repr(attrs
, span
, target
, item
, hir_id
);
194 self.check_used(attrs
, target
);
197 fn inline_attr_str_error_with_macro_def(&self, hir_id
: HirId
, attr
: &Attribute
, sym
: &str) {
198 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
200 "`#[{}]` is ignored on struct fields, match arms and macro defs",
204 "this was previously accepted by the compiler but is \
205 being phased out; it will become a hard error in \
209 "see issue #80564 <https://github.com/rust-lang/rust/issues/80564> \
210 for more information",
216 fn inline_attr_str_error_without_macro_def(&self, hir_id
: HirId
, attr
: &Attribute
, sym
: &str) {
217 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
218 lint
.build(&format
!("`#[{}]` is ignored on struct fields and match arms", sym
))
220 "this was previously accepted by the compiler but is \
221 being phased out; it will become a hard error in \
225 "see issue #80564 <https://github.com/rust-lang/rust/issues/80564> \
226 for more information",
232 /// Checks if an `#[inline]` is applied to a function or a closure. Returns `true` if valid.
233 fn check_inline(&self, hir_id
: HirId
, attr
: &Attribute
, span
: &Span
, target
: Target
) -> bool
{
237 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
238 Target
::Method(MethodKind
::Trait { body: false }
) | Target
::ForeignFn
=> {
239 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
240 lint
.build("`#[inline]` is ignored on function prototypes").emit()
244 // FIXME(#65833): We permit associated consts to have an `#[inline]` attribute with
245 // just a lint, because we previously erroneously allowed it and some crates used it
246 // accidentally, to to be compatible with crates depending on them, we can't throw an
248 Target
::AssocConst
=> {
249 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
250 lint
.build("`#[inline]` is ignored on constants")
252 "this was previously accepted by the compiler but is \
253 being phased out; it will become a hard error in \
257 "see issue #65833 <https://github.com/rust-lang/rust/issues/65833> \
258 for more information",
264 // FIXME(#80564): Same for fields, arms, and macro defs
265 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
266 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "inline");
274 "attribute should be applied to function or closure",
276 .span_label(*span
, "not a function or closure")
283 fn check_generic_attr(
288 allowed_targets
: &[Target
],
290 if !allowed_targets
.iter().any(|t
| t
== &target
) {
291 let name
= attr
.name_or_empty();
292 let mut i
= allowed_targets
.iter();
294 let b
= i
.next().map_or_else(String
::new
, |t
| t
.to_string() + "s");
295 let supported_names
= i
.enumerate().fold(b
, |mut b
, (i
, allowed_target
)| {
296 if allowed_targets
.len() > 2 && i
== allowed_targets
.len() - 2 {
297 b
.push_str(", and ");
298 } else if allowed_targets
.len() == 2 && i
== allowed_targets
.len() - 2 {
304 b
.push_str(&(allowed_target
.to_string() + "s"));
307 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
308 lint
.build(&format
!("`#[{name}]` only has an effect on {}", supported_names
))
314 /// Checks if `#[naked]` is applied to a function definition.
315 fn check_naked(&self, hir_id
: HirId
, attr
: &Attribute
, span
: &Span
, target
: Target
) -> bool
{
318 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
319 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
320 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
321 // erroneously allowed it and some crates used it accidentally, to to be compatible
322 // with crates depending on them, we can't throw an error here.
323 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
324 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "naked");
332 "attribute should be applied to a function definition",
334 .span_label(*span
, "not a function definition")
341 /// Checks if `#[cmse_nonsecure_entry]` is applied to a function definition.
342 fn check_cmse_nonsecure_entry(&self, attr
: &Attribute
, span
: &Span
, target
: Target
) -> bool
{
345 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
351 "attribute should be applied to a function definition",
353 .span_label(*span
, "not a function definition")
360 /// Checks if a `#[track_caller]` is applied to a non-naked function. Returns `true` if valid.
361 fn check_track_caller(
365 attrs
: &'hir
[Attribute
],
370 _
if attrs
.iter().any(|attr
| attr
.has_name(sym
::naked
)) => {
375 "cannot use `#[track_caller]` with `#[naked]`",
380 Target
::Fn
| Target
::Method(..) | Target
::ForeignFn
| Target
::Closure
=> true,
381 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
382 // `#[track_caller]` attribute with just a lint, because we previously
383 // erroneously allowed it and some crates used it accidentally, to to be compatible
384 // with crates depending on them, we can't throw an error here.
385 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
387 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "track_caller");
396 "attribute should be applied to function"
398 .span_label(*span
, "not a function")
405 /// Checks if the `#[non_exhaustive]` attribute on an `item` is valid. Returns `true` if valid.
406 fn check_non_exhaustive(
414 Target
::Struct
| Target
::Enum
| Target
::Variant
=> true,
415 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
416 // `#[non_exhaustive]` attribute with just a lint, because we previously
417 // erroneously allowed it and some crates used it accidentally, to to be compatible
418 // with crates depending on them, we can't throw an error here.
419 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
420 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "non_exhaustive");
428 "attribute can only be applied to a struct or enum"
430 .span_label(*span
, "not a struct or enum")
437 /// Checks if the `#[marker]` attribute on an `item` is valid. Returns `true` if valid.
438 fn check_marker(&self, hir_id
: HirId
, attr
: &Attribute
, span
: &Span
, target
: Target
) -> bool
{
440 Target
::Trait
=> true,
441 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
442 // `#[marker]` attribute with just a lint, because we previously
443 // erroneously allowed it and some crates used it accidentally, to to be compatible
444 // with crates depending on them, we can't throw an error here.
445 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
446 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "marker");
452 .struct_span_err(attr
.span
, "attribute can only be applied to a trait")
453 .span_label(*span
, "not a trait")
460 /// Checks if the `#[target_feature]` attribute on `item` is valid. Returns `true` if valid.
461 fn check_target_feature(
470 | Target
::Method(MethodKind
::Trait { body: true }
| MethodKind
::Inherent
) => true,
471 // FIXME: #[target_feature] was previously erroneously allowed on statements and some
472 // crates used this, so only emit a warning.
473 Target
::Statement
=> {
474 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
475 lint
.build("attribute should be applied to a function")
477 "this was previously accepted by the compiler but is \
478 being phased out; it will become a hard error in \
481 .span_label(*span
, "not a function")
486 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
487 // `#[target_feature]` attribute with just a lint, because we previously
488 // erroneously allowed it and some crates used it accidentally, to 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
, "target_feature");
497 .struct_span_err(attr
.span
, "attribute should be applied to a function")
498 .span_label(*span
, "not a function")
505 fn doc_attr_str_error(&self, meta
: &NestedMetaItem
, attr_name
: &str) {
510 &format
!("doc {0} attribute expects a string: #[doc({0} = \"a\")]", attr_name
),
515 fn check_doc_alias_value(
517 meta
: &NestedMetaItem
,
522 aliases
: &mut FxHashMap
<String
, Span
>,
525 let err_fn
= move |span
: Span
, msg
: &str| {
529 "`#[doc(alias{})]` {}",
530 if is_list { "(\"...\")" }
else { " = \"...\"" }
,
536 if doc_alias
.is_empty() {
538 meta
.name_value_literal_span().unwrap_or_else(|| meta
.span()),
539 "attribute cannot have empty value",
543 doc_alias
.chars().find(|&c
| c
== '
"' || c == '\'' || (c.is_whitespace() && c != ' '))
545 self.tcx.sess.span_err(
546 meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
548 "{:?} character isn't allowed
in `
#[doc(alias{})]`",
550 if is_list { "(\"...\")" } else { " = \"...\"" },
555 if doc_alias.starts_with(' ') || doc_alias.ends_with(' ') {
557 meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
558 "cannot start or end with ' '",
561 if let Some(err) = match target {
562 Target::Impl => Some("implementation block"),
563 Target::ForeignMod => Some("extern block"),
565 let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
566 let containing_item = self.tcx.hir().expect_item(parent_hir_id);
567 if Target::from_item(containing_item) == Target::Impl {
568 Some("type alias in implementation block")
573 Target::AssocConst => {
574 let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
575 let containing_item = self.tcx.hir().expect_item(parent_hir_id);
576 // We can't link to trait impl's consts.
577 let err = "associated constant in trait implementation block";
578 match containing_item.kind {
579 ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => Some(err),
583 // we check the validity of params elsewhere
584 Target::Param => return false,
587 return err_fn(meta.span(), &format!("isn't allowed on {}", err));
589 let item_name = self.tcx.hir().name(hir_id);
590 if &*item_name.as_str() == doc_alias {
591 return err_fn(meta.span(), "is the same as the item's name");
593 let span = meta.span();
594 if let Err(entry) = aliases.try_insert(doc_alias.to_owned(), span) {
595 self.tcx.struct_span_lint_hir(UNUSED_ATTRIBUTES, hir_id, span, |lint| {
596 lint.build("doc alias is duplicated")
597 .span_label(*entry.entry.get(), "first defined here")
606 meta: &NestedMetaItem,
609 aliases: &mut FxHashMap<String, Span>,
611 if let Some(values) = meta.meta_item_list() {
615 Some(l) => match l.kind {
616 LitKind::Str(s, _) => {
617 if !self.check_doc_alias_value(
633 "`#[doc(alias(\"a\"))]` expects string literals",
644 "`#[doc(alias(\"a\"))]` expects string literals",
652 } else if let Some(doc_alias) = meta.value_str().map(|s| s.to_string()) {
653 self.check_doc_alias_value(meta, &doc_alias, hir_id, target, false, aliases)
659 "doc alias attribute expects a string `#[doc(alias = \"a\")]` or a list of \
660 strings `#[doc(alias(\"a\", \"b\"))]`",
667 fn check_doc_keyword(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
668 let doc_keyword = meta.value_str().map(|s| s.to_string()).unwrap_or_else(String::new);
669 if doc_keyword.is_empty() {
670 self.doc_attr_str_error(meta, "keyword");
673 match self.tcx.hir().find(hir_id).and_then(|node| match node {
674 hir::Node::Item(item) => Some(&item.kind),
677 Some(ItemKind::Mod(ref module)) => {
678 if !module.item_ids.is_empty() {
683 "`#[doc(keyword = \"...\")]` can only be used on empty modules",
694 "`#[doc(keyword = \"...\")]` can only be used on modules",
700 if !rustc_lexer::is_ident(&doc_keyword) {
704 meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
705 &format!("`{}` is not a valid identifier", doc_keyword),
713 /// Checks `#[doc(inline)]`/`#[doc(no_inline)]` attributes. Returns `true` if valid.
715 /// A doc inlining attribute is invalid if it is applied to a non-`use` item, or
716 /// if there are conflicting attributes for one item.
718 /// `specified_inline` is used to keep track of whether we have
719 /// already seen an inlining attribute for this item.
720 /// If so, `specified_inline` holds the value and the span of
721 /// the first `inline`/`no_inline` attribute.
725 meta: &NestedMetaItem,
728 specified_inline: &mut Option<(bool, Span)>,
730 if target == Target::Use || target == Target::ExternCrate {
731 let do_inline = meta.name_or_empty() == sym::inline;
732 if let Some((prev_inline, prev_span)) = *specified_inline {
733 if do_inline != prev_inline {
734 let mut spans = MultiSpan::from_spans(vec![prev_span, meta.span()]);
735 spans.push_span_label(prev_span, String::from("this attribute..."));
736 spans.push_span_label(
738 String::from("...conflicts with this attribute"),
742 .struct_span_err(spans, "conflicting doc inlining attributes")
743 .help("remove one of the conflicting attributes")
749 *specified_inline = Some((do_inline, meta.span()));
753 self.tcx.struct_span_lint_hir(
754 INVALID_DOC_ATTRIBUTES,
758 let mut err = lint.build(
759 "this attribute can only be applied to a `use` item",
761 err.span_label(meta.span(), "only applicable on `use` items");
762 if attr.style == AttrStyle::Outer {
764 self.tcx.hir().span(hir_id),
768 err.note("read https://doc.rust-lang.org/nightly/rustdoc/the-doc-attribute.html#docno_inlinedocinline for more information")
776 /// Checks that an attribute is *not* used at the crate level. Returns `true` if valid.
777 fn check_attr_not_crate_level(
779 meta
: &NestedMetaItem
,
783 if CRATE_HIR_ID
== hir_id
{
789 "`#![doc({} = \"...\")]` isn't allowed as a crate-level attribute",
799 /// Checks that an attribute is used at the crate level. Returns `true` if valid.
800 fn check_attr_crate_level(
803 meta
: &NestedMetaItem
,
806 if hir_id
!= CRATE_HIR_ID
{
807 self.tcx
.struct_span_lint_hir(
808 INVALID_DOC_ATTRIBUTES
,
812 let mut err
= lint
.build(
813 "this attribute can only be applied at the crate level",
815 if attr
.style
== AttrStyle
::Outer
&& self.tcx
.hir().get_parent_item(hir_id
) == CRATE_HIR_ID
{
817 self.tcx
.sess
.source_map().span_to_snippet(attr
.span
)
820 err
.span_suggestion_verbose(
822 "to apply to the crate, use an inner attribute",
824 Applicability
::MaybeIncorrect
,
829 "to apply to the crate, use an inner attribute",
833 err
.note("read https://doc.rust-lang.org/nightly/rustdoc/the-doc-attribute.html#at-the-crate-level for more information")
842 /// Checks that `doc(test(...))` attribute contains only valid attributes. Returns `true` if
844 fn check_test_attr(&self, meta
: &NestedMetaItem
, hir_id
: HirId
) -> bool
{
845 let mut is_valid
= true;
846 if let Some(metas
) = meta
.meta_item_list() {
847 for i_meta
in metas
{
848 match i_meta
.name_or_empty() {
849 sym
::attr
| sym
::no_crate_inject
=> {}
851 self.tcx
.struct_span_lint_hir(
852 INVALID_DOC_ATTRIBUTES
,
857 "unknown `doc(test)` attribute `{}`",
858 rustc_ast_pretty
::pprust
::path_to_string(
859 &i_meta
.meta_item().unwrap().path
870 self.tcx
.struct_span_lint_hir(INVALID_DOC_ATTRIBUTES
, hir_id
, meta
.span(), |lint
| {
871 lint
.build("`#[doc(test(...)]` takes a list of attributes").emit();
878 /// Runs various checks on `#[doc]` attributes. Returns `true` if valid.
880 /// `specified_inline` should be initialized to `None` and kept for the scope
881 /// of one item. Read the documentation of [`check_doc_inline`] for more information.
883 /// [`check_doc_inline`]: Self::check_doc_inline
889 specified_inline
: &mut Option
<(bool
, Span
)>,
890 aliases
: &mut FxHashMap
<String
, Span
>,
892 let mut is_valid
= true;
894 if let Some(list
) = attr
.meta().and_then(|mi
| mi
.meta_item_list().map(|l
| l
.to_vec())) {
896 if let Some(i_meta
) = meta
.meta_item() {
897 match i_meta
.name_or_empty() {
899 if !self.check_attr_not_crate_level(&meta
, hir_id
, "alias")
900 || !self.check_doc_alias(&meta
, hir_id
, target
, aliases
) =>
906 if !self.check_attr_not_crate_level(&meta
, hir_id
, "keyword")
907 || !self.check_doc_keyword(&meta
, hir_id
) =>
912 sym
::html_favicon_url
914 | sym
::html_playground_url
915 | sym
::issue_tracker_base_url
917 | sym
::html_no_source
919 if !self.check_attr_crate_level(&attr
, &meta
, hir_id
) =>
924 sym
::inline
| sym
::no_inline
925 if !self.check_doc_inline(
936 // no_default_passes: deprecated
937 // passes: deprecated
938 // plugins: removed, but rustdoc warns about it itself
943 | sym
::html_favicon_url
945 | sym
::html_no_source
946 | sym
::html_playground_url
949 | sym
::issue_tracker_base_url
952 | sym
::no_default_passes
959 if !self.check_test_attr(&meta
, hir_id
) {
965 if !self.tcx
.features().doc_primitive
{
966 self.tcx
.struct_span_lint_hir(
967 INVALID_DOC_ATTRIBUTES
,
971 let mut diag
= lint
.build(
972 "`doc(primitive)` should never have been stable",
981 self.tcx
.struct_span_lint_hir(
982 INVALID_DOC_ATTRIBUTES
,
986 let mut diag
= lint
.build(&format
!(
987 "unknown `doc` attribute `{}`",
988 rustc_ast_pretty
::pprust
::path_to_string(&i_meta
.path
),
990 if i_meta
.has_name(sym
::spotlight
) {
992 "`doc(spotlight)` was renamed to `doc(notable_trait)`",
994 diag
.span_suggestion_short(
996 "use `notable_trait` instead",
997 String
::from("notable_trait"),
998 Applicability
::MachineApplicable
,
1000 diag
.note("`doc(spotlight)` is now a no-op");
1002 if i_meta
.has_name(sym
::include
) {
1003 if let Some(value
) = i_meta
.value_str() {
1004 // if there are multiple attributes, the suggestion would suggest deleting all of them, which is incorrect
1005 let applicability
= if list
.len() == 1 {
1006 Applicability
::MachineApplicable
1008 Applicability
::MaybeIncorrect
1010 let inner
= if attr
.style
== AttrStyle
::Inner
{
1015 diag
.span_suggestion(
1016 attr
.meta().unwrap().span
,
1017 "use `doc = include_str!` instead",
1019 "#{}[doc = include_str!(\"{}\")]",
1033 self.tcx
.struct_span_lint_hir(
1034 INVALID_DOC_ATTRIBUTES
,
1038 lint
.build(&"invalid `doc` attribute").emit();
1049 /// Checks if `#[must_not_suspend]` is applied to a function. Returns `true` if valid.
1050 fn check_must_not_suspend(&self, attr
: &Attribute
, span
: &Span
, target
: Target
) -> bool
{
1052 Target
::Struct
| Target
::Enum
| Target
::Union
| Target
::Trait
=> true,
1056 .struct_span_err(attr
.span
, "`must_not_suspend` attribute should be applied to a struct, enum, or trait")
1057 .span_label(*span
, "is not a struct, enum, or trait")
1064 /// Checks if `#[cold]` is applied to a non-function. Returns `true` if valid.
1065 fn check_cold(&self, hir_id
: HirId
, attr
: &Attribute
, span
: &Span
, target
: Target
) {
1067 Target
::Fn
| Target
::Method(..) | Target
::ForeignFn
| Target
::Closure
=> {}
1068 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1069 // `#[cold]` attribute with just a lint, because we previously
1070 // erroneously allowed it and some crates used it accidentally, to to be compatible
1071 // with crates depending on them, we can't throw an error here.
1072 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
1073 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "cold");
1076 // FIXME: #[cold] was previously allowed on non-functions and some crates used
1077 // this, so only emit a warning.
1078 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1079 lint
.build("attribute should be applied to a function")
1081 "this was previously accepted by the compiler but is \
1082 being phased out; it will become a hard error in \
1085 .span_label(*span
, "not a function")
1092 /// Checks if `#[link_name]` is applied to an item other than a foreign function or static.
1093 fn check_link_name(&self, hir_id
: HirId
, attr
: &Attribute
, span
: &Span
, target
: Target
) {
1095 Target
::ForeignFn
| Target
::ForeignStatic
=> {}
1096 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1097 // `#[link_name]` attribute with just a lint, because we previously
1098 // erroneously allowed it and some crates used it accidentally, to to be compatible
1099 // with crates depending on them, we can't throw an error here.
1100 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
1101 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "link_name");
1104 // FIXME: #[cold] was previously allowed on non-functions/statics and some crates
1105 // used this, so only emit a warning.
1106 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1108 lint
.build("attribute should be applied to a foreign function or static");
1110 "this was previously accepted by the compiler but is \
1111 being phased out; it will become a hard error in \
1116 if let Target
::ForeignMod
= target
{
1117 if let Some(value
) = attr
.value_str() {
1120 &format
!(r
#"try `#[link(name = "{}")]` instead"#, value),
1123 diag
.span_help(attr
.span
, r
#"try `#[link(name = "...")]` instead"#);
1127 diag
.span_label(*span
, "not a foreign function or static");
1134 /// Checks if `#[no_link]` is applied to an `extern crate`. Returns `true` if valid.
1135 fn check_no_link(&self, hir_id
: HirId
, attr
: &Attribute
, span
: &Span
, target
: Target
) -> bool
{
1137 Target
::ExternCrate
=> true,
1138 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1139 // `#[no_link]` attribute with just a lint, because we previously
1140 // erroneously allowed it and some crates used it accidentally, to to be compatible
1141 // with crates depending on them, we can't throw an error here.
1142 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
1143 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "no_link");
1151 "attribute should be applied to an `extern crate` item",
1153 .span_label(*span
, "not an `extern crate` item")
1160 fn is_impl_item(&self, hir_id
: HirId
) -> bool
{
1161 matches
!(self.tcx
.hir().get(hir_id
), hir
::Node
::ImplItem(..))
1164 /// Checks if `#[export_name]` is applied to a function or static. Returns `true` if valid.
1165 fn check_export_name(
1173 Target
::Static
| Target
::Fn
=> true,
1174 Target
::Method(..) if self.is_impl_item(hir_id
) => true,
1175 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1176 // `#[export_name]` attribute with just a lint, because we previously
1177 // erroneously allowed it and some crates used it accidentally, to to be compatible
1178 // with crates depending on them, we can't throw an error here.
1179 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
1180 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "export_name");
1188 "attribute should be applied to a free function, impl method or static",
1190 .span_label(*span
, "not a free function, impl method or static")
1197 fn check_rustc_layout_scalar_valid_range(
1203 if target
!= Target
::Struct
{
1206 .struct_span_err(attr
.span
, "attribute should be applied to a struct")
1207 .span_label(*span
, "not a struct")
1212 let list
= match attr
.meta_item_list() {
1213 None
=> return false,
1217 if matches
!(&list
[..], &[NestedMetaItem
::Literal(Lit { kind: LitKind::Int(..), .. }
)]) {
1222 .struct_span_err(attr
.span
, "expected exactly one integer literal argument")
1228 /// Checks if `#[rustc_legacy_const_generics]` is applied to a function and has a valid argument.
1229 fn check_rustc_legacy_const_generics(
1234 item
: Option
<ItemLike
<'_
>>,
1236 let is_function
= matches
!(target
, Target
::Fn
| Target
::Method(..));
1240 .struct_span_err(attr
.span
, "attribute should be applied to a function")
1241 .span_label(*span
, "not a function")
1246 let list
= match attr
.meta_item_list() {
1247 // The attribute form is validated on AST.
1248 None
=> return false,
1252 let (decl
, generics
) = match item
{
1253 Some(ItemLike
::Item(Item
{
1254 kind
: ItemKind
::Fn(FnSig { decl, .. }
, generics
, _
),
1256 })) => (decl
, generics
),
1257 _
=> bug
!("should be a function item"),
1260 for param
in generics
.params
{
1262 hir
::GenericParamKind
::Const { .. }
=> {}
1268 "#[rustc_legacy_const_generics] functions must \
1269 only have const generics",
1271 .span_label(param
.span
, "non-const generic parameter")
1278 if list
.len() != generics
.params
.len() {
1283 "#[rustc_legacy_const_generics] must have one index for each generic parameter",
1285 .span_label(generics
.span
, "generic parameters")
1290 let arg_count
= decl
.inputs
.len() as u128
+ generics
.params
.len() as u128
;
1291 let mut invalid_args
= vec
![];
1293 if let Some(LitKind
::Int(val
, _
)) = meta
.literal().map(|lit
| &lit
.kind
) {
1294 if *val
>= arg_count
{
1295 let span
= meta
.span();
1298 .struct_span_err(span
, "index exceeds number of arguments")
1302 "there {} only {} argument{}",
1303 if arg_count
!= 1 { "are" }
else { "is" }
,
1305 pluralize
!(arg_count
)
1312 invalid_args
.push(meta
.span());
1316 if !invalid_args
.is_empty() {
1319 .struct_span_err(invalid_args
, "arguments should be non-negative integers")
1327 /// Checks that the dep-graph debugging attributes are only present when the query-dep-graph
1328 /// option is passed to the compiler.
1329 fn check_rustc_dirty_clean(&self, attr
: &Attribute
) -> bool
{
1330 if self.tcx
.sess
.opts
.debugging_opts
.query_dep_graph
{
1335 .struct_span_err(attr
.span
, "attribute requires -Z query-dep-graph to be enabled")
1341 /// Checks if `#[link_section]` is applied to a function or static.
1342 fn check_link_section(&self, hir_id
: HirId
, attr
: &Attribute
, span
: &Span
, target
: Target
) {
1344 Target
::Static
| Target
::Fn
| Target
::Method(..) => {}
1345 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1346 // `#[link_section]` attribute with just a lint, because we previously
1347 // erroneously allowed it and some crates used it accidentally, to to be compatible
1348 // with crates depending on them, we can't throw an error here.
1349 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
1350 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "link_section");
1353 // FIXME: #[link_section] was previously allowed on non-functions/statics and some
1354 // crates used this, so only emit a warning.
1355 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1356 lint
.build("attribute should be applied to a function or static")
1358 "this was previously accepted by the compiler but is \
1359 being phased out; it will become a hard error in \
1362 .span_label(*span
, "not a function or static")
1369 /// Checks if `#[no_mangle]` is applied to a function or static.
1370 fn check_no_mangle(&self, hir_id
: HirId
, attr
: &Attribute
, span
: &Span
, target
: Target
) {
1372 Target
::Static
| Target
::Fn
=> {}
1373 Target
::Method(..) if self.is_impl_item(hir_id
) => {}
1374 // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
1375 // `#[no_mangle]` attribute with just a lint, because we previously
1376 // erroneously allowed it and some crates used it accidentally, to to be compatible
1377 // with crates depending on them, we can't throw an error here.
1378 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
1379 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "no_mangle");
1381 // FIXME: #[no_mangle] was previously allowed on non-functions/statics, this should be an error
1382 // The error should specify that the item that is wrong is specifically a *foreign* fn/static
1383 // otherwise the error seems odd
1384 Target
::ForeignFn
| Target
::ForeignStatic
=> {
1385 let foreign_item_kind
= match target
{
1386 Target
::ForeignFn
=> "function",
1387 Target
::ForeignStatic
=> "static",
1388 _
=> unreachable
!(),
1390 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1391 lint
.build(&format
!(
1392 "`#[no_mangle]` has no effect on a foreign {}",
1396 "this was previously accepted by the compiler but is \
1397 being phased out; it will become a hard error in \
1400 .span_label(*span
, format
!("foreign {}", foreign_item_kind
))
1401 .note("symbol names in extern blocks are not mangled")
1404 "remove this attribute",
1406 Applicability
::MachineApplicable
,
1412 // FIXME: #[no_mangle] was previously allowed on non-functions/statics and some
1413 // crates used this, so only emit a warning.
1414 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1416 "attribute should be applied to a free function, impl method or static",
1419 "this was previously accepted by the compiler but is \
1420 being phased out; it will become a hard error in \
1423 .span_label(*span
, "not a free function, impl method or static")
1430 /// Checks if the `#[repr]` attributes on `item` are valid.
1433 attrs
: &'hir
[Attribute
],
1436 item
: Option
<ItemLike
<'_
>>,
1439 // Extract the names of all repr hints, e.g., [foo, bar, align] for:
1442 // #[repr(bar, align(8))]
1444 let hints
: Vec
<_
> = attrs
1446 .filter(|attr
| attr
.has_name(sym
::repr
))
1447 .filter_map(|attr
| attr
.meta_item_list())
1451 let mut int_reprs
= 0;
1452 let mut is_c
= false;
1453 let mut is_simd
= false;
1454 let mut is_transparent
= false;
1456 for hint
in &hints
{
1457 if !hint
.is_meta_item() {
1462 "meta item in `repr` must be an identifier"
1468 let (article
, allowed_targets
) = match hint
.name_or_empty() {
1472 Target
::Struct
| Target
::Union
| Target
::Enum
=> continue,
1473 _
=> ("a", "struct, enum, or union"),
1477 if let (Target
::Fn
, true) = (target
, !self.tcx
.features().fn_align
) {
1479 &self.tcx
.sess
.parse_sess
,
1482 "`repr(align)` attributes on functions are unstable",
1488 Target
::Struct
| Target
::Union
| Target
::Enum
| Target
::Fn
=> continue,
1489 _
=> ("a", "struct, enum, function, or union"),
1493 if target
!= Target
::Struct
&& target
!= Target
::Union
{
1494 ("a", "struct or union")
1501 if target
!= Target
::Struct
{
1507 sym
::transparent
=> {
1508 is_transparent
= true;
1510 Target
::Struct
| Target
::Union
| Target
::Enum
=> continue,
1511 _
=> ("a", "struct, enum, or union"),
1515 if !self.tcx
.features().enabled(sym
::no_niche
) {
1517 &self.tcx
.sess
.parse_sess
,
1520 "the attribute `repr(no_niche)` is currently unstable",
1525 Target
::Struct
| Target
::Enum
=> continue,
1526 _
=> ("a", "struct or enum"),
1542 if target
!= Target
::Enum
{
1553 "unrecognized representation hint"
1566 &format
!("attribute should be applied to {} {}", article
, allowed_targets
)
1568 .span_label(*span
, &format
!("not {} {}", article
, allowed_targets
))
1572 // Just point at all repr hints if there are any incompatibilities.
1573 // This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
1574 let hint_spans
= hints
.iter().map(|hint
| hint
.span());
1576 // Error on repr(transparent, <anything else apart from no_niche>).
1577 let non_no_niche
= |hint
: &&NestedMetaItem
| hint
.name_or_empty() != sym
::no_niche
;
1578 let non_no_niche_count
= hints
.iter().filter(non_no_niche
).count();
1579 if is_transparent
&& non_no_niche_count
> 1 {
1580 let hint_spans
: Vec
<_
> = hint_spans
.clone().collect();
1585 "transparent {} cannot have other repr hints",
1590 // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
1592 || (is_simd
&& is_c
)
1595 && item
.map_or(false, |item
| {
1596 if let ItemLike
::Item(item
) = item
{
1597 return is_c_like_enum(item
);
1602 self.tcx
.struct_span_lint_hir(
1603 CONFLICTING_REPR_HINTS
,
1605 hint_spans
.collect
::<Vec
<Span
>>(),
1607 lint
.build("conflicting representation hints")
1608 .code(rustc_errors
::error_code
!(E0566
))
1615 fn check_used(&self, attrs
: &'hir
[Attribute
], target
: Target
) {
1617 if attr
.has_name(sym
::used
) && target
!= Target
::Static
{
1620 .span_err(attr
.span
, "attribute must be applied to a `static` variable");
1625 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1626 /// (Allows proc_macro functions)
1627 fn check_allow_internal_unstable(
1633 attrs
: &[Attribute
],
1635 debug
!("Checking target: {:?}", target
);
1639 if self.tcx
.sess
.is_proc_macro_attr(attr
) {
1640 debug
!("Is proc macro attr");
1644 debug
!("Is not proc macro attr");
1647 Target
::MacroDef
=> true,
1648 // FIXME(#80564): We permit struct fields and match arms to have an
1649 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1650 // erroneously allowed it and some crates used it accidentally, to to be compatible
1651 // with crates depending on them, we can't throw an error here.
1652 Target
::Field
| Target
::Arm
=> {
1653 self.inline_attr_str_error_without_macro_def(
1656 "allow_internal_unstable",
1663 .struct_span_err(attr
.span
, "attribute should be applied to a macro")
1664 .span_label(*span
, "not a macro")
1671 /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
1672 /// (Allows proc_macro functions)
1673 fn check_rustc_allow_const_fn_unstable(
1681 Target
::Fn
| Target
::Method(_
)
1682 if self.tcx
.is_const_fn_raw(self.tcx
.hir().local_def_id(hir_id
)) =>
1686 // FIXME(#80564): We permit struct fields and match arms to have an
1687 // `#[allow_internal_unstable]` attribute with just a lint, because we previously
1688 // erroneously allowed it and some crates used it accidentally, to to be compatible
1689 // with crates depending on them, we can't throw an error here.
1690 Target
::Field
| Target
::Arm
| Target
::MacroDef
=> {
1691 self.inline_attr_str_error_with_macro_def(hir_id
, attr
, "allow_internal_unstable");
1697 .struct_span_err(attr
.span
, "attribute should be applied to `const fn`")
1698 .span_label(*span
, "not a `const fn`")
1705 /// default_method_body_is_const should only be applied to trait methods with default bodies.
1706 fn check_default_method_body_is_const(
1713 Target
::Method(MethodKind
::Trait { body: true }
) => true,
1719 "attribute should be applied to a trait method with body",
1721 .span_label(*span
, "not a trait method or missing a body")
1728 fn check_stability_promotable(&self, attr
: &Attribute
, _span
: &Span
, target
: Target
) -> bool
{
1730 Target
::Expression
=> {
1733 .struct_span_err(attr
.span
, "attribute cannot be applied to an expression")
1741 fn check_deprecated(&self, hir_id
: HirId
, attr
: &Attribute
, _span
: &Span
, target
: Target
) {
1743 Target
::Closure
| Target
::Expression
| Target
::Statement
| Target
::Arm
=> {
1744 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1745 lint
.build("attribute is ignored here").emit();
1752 fn check_macro_use(&self, hir_id
: HirId
, attr
: &Attribute
, target
: Target
) {
1753 let name
= attr
.name_or_empty();
1755 Target
::ExternCrate
| Target
::Mod
=> {}
1757 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1758 lint
.build(&format
!(
1759 "`#[{name}]` only has an effect on `extern crate` and modules"
1767 fn check_macro_export(&self, hir_id
: HirId
, attr
: &Attribute
, target
: Target
) {
1768 if target
!= Target
::MacroDef
{
1769 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1770 lint
.build("`#[macro_export]` only has an effect on macro definitions").emit();
1775 fn check_cfg_attr(&self, hir_id
: HirId
, attr
: &Attribute
) {
1776 if let Some((_
, attrs
)) = rustc_parse
::parse_cfg_attr(&attr
, &self.tcx
.sess
.parse_sess
) {
1777 if attrs
.is_empty() {
1778 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1779 lint
.build("`#[cfg_attr]` does not expand to any attributes").emit();
1785 fn check_plugin_registrar(&self, hir_id
: HirId
, attr
: &Attribute
, target
: Target
) {
1786 if target
!= Target
::Fn
{
1787 self.tcx
.struct_span_lint_hir(UNUSED_ATTRIBUTES
, hir_id
, attr
.span
, |lint
| {
1788 lint
.build("`#[plugin_registrar]` only has an effect on functions").emit();
1794 impl Visitor
<'tcx
> for CheckAttrVisitor
<'tcx
> {
1795 type Map
= Map
<'tcx
>;
1797 fn nested_visit_map(&mut self) -> NestedVisitorMap
<Self::Map
> {
1798 NestedVisitorMap
::OnlyBodies(self.tcx
.hir())
1801 fn visit_item(&mut self, item
: &'tcx Item
<'tcx
>) {
1802 // Historically we've run more checks on non-exported than exported macros,
1803 // so this lets us continue to run them while maintaining backwards compatibility.
1804 // In the long run, the checks should be harmonized.
1805 if let ItemKind
::Macro(ref macro_def
) = item
.kind
{
1806 let def_id
= item
.def_id
.to_def_id();
1807 if macro_def
.macro_rules
&& !self.tcx
.has_attr(def_id
, sym
::macro_export
) {
1808 check_non_exported_macro_for_invalid_attrs(self.tcx
, item
);
1812 let target
= Target
::from_item(item
);
1813 self.check_attributes(item
.hir_id(), &item
.span
, target
, Some(ItemLike
::Item(item
)));
1814 intravisit
::walk_item(self, item
)
1817 fn visit_generic_param(&mut self, generic_param
: &'tcx hir
::GenericParam
<'tcx
>) {
1818 let target
= Target
::from_generic_param(generic_param
);
1819 self.check_attributes(generic_param
.hir_id
, &generic_param
.span
, target
, None
);
1820 intravisit
::walk_generic_param(self, generic_param
)
1823 fn visit_trait_item(&mut self, trait_item
: &'tcx TraitItem
<'tcx
>) {
1824 let target
= Target
::from_trait_item(trait_item
);
1825 self.check_attributes(trait_item
.hir_id(), &trait_item
.span
, target
, None
);
1826 intravisit
::walk_trait_item(self, trait_item
)
1829 fn visit_field_def(&mut self, struct_field
: &'tcx hir
::FieldDef
<'tcx
>) {
1830 self.check_attributes(struct_field
.hir_id
, &struct_field
.span
, Target
::Field
, None
);
1831 intravisit
::walk_field_def(self, struct_field
);
1834 fn visit_arm(&mut self, arm
: &'tcx hir
::Arm
<'tcx
>) {
1835 self.check_attributes(arm
.hir_id
, &arm
.span
, Target
::Arm
, None
);
1836 intravisit
::walk_arm(self, arm
);
1839 fn visit_foreign_item(&mut self, f_item
: &'tcx ForeignItem
<'tcx
>) {
1840 let target
= Target
::from_foreign_item(f_item
);
1841 self.check_attributes(
1845 Some(ItemLike
::ForeignItem(f_item
)),
1847 intravisit
::walk_foreign_item(self, f_item
)
1850 fn visit_impl_item(&mut self, impl_item
: &'tcx hir
::ImplItem
<'tcx
>) {
1851 let target
= target_from_impl_item(self.tcx
, impl_item
);
1852 self.check_attributes(impl_item
.hir_id(), &impl_item
.span
, target
, None
);
1853 intravisit
::walk_impl_item(self, impl_item
)
1856 fn visit_stmt(&mut self, stmt
: &'tcx hir
::Stmt
<'tcx
>) {
1857 // When checking statements ignore expressions, they will be checked later.
1858 if let hir
::StmtKind
::Local(ref l
) = stmt
.kind
{
1859 self.check_attributes(l
.hir_id
, &stmt
.span
, Target
::Statement
, None
);
1861 intravisit
::walk_stmt(self, stmt
)
1864 fn visit_expr(&mut self, expr
: &'tcx hir
::Expr
<'tcx
>) {
1865 let target
= match expr
.kind
{
1866 hir
::ExprKind
::Closure(..) => Target
::Closure
,
1867 _
=> Target
::Expression
,
1870 self.check_attributes(expr
.hir_id
, &expr
.span
, target
, None
);
1871 intravisit
::walk_expr(self, expr
)
1876 variant
: &'tcx hir
::Variant
<'tcx
>,
1877 generics
: &'tcx hir
::Generics
<'tcx
>,
1880 self.check_attributes(variant
.id
, &variant
.span
, Target
::Variant
, None
);
1881 intravisit
::walk_variant(self, variant
, generics
, item_id
)
1884 fn visit_param(&mut self, param
: &'tcx hir
::Param
<'tcx
>) {
1885 self.check_attributes(param
.hir_id
, ¶m
.span
, Target
::Param
, None
);
1887 intravisit
::walk_param(self, param
);
1891 fn is_c_like_enum(item
: &Item
<'_
>) -> bool
{
1892 if let ItemKind
::Enum(ref def
, _
) = item
.kind
{
1893 for variant
in def
.variants
{
1894 match variant
.data
{
1895 hir
::VariantData
::Unit(..) => { /* continue */ }
1905 fn check_invalid_crate_level_attr(tcx
: TyCtxt
<'_
>, attrs
: &[Attribute
]) {
1906 const ATTRS_TO_CHECK
: &[Symbol
] = &[
1910 sym
::automatically_derived
,
1916 for attr_to_check
in ATTRS_TO_CHECK
{
1917 if attr
.has_name(*attr_to_check
) {
1922 "`{}` attribute cannot be used at crate level",
1923 attr_to_check
.to_ident_string()
1932 fn check_non_exported_macro_for_invalid_attrs(tcx
: TyCtxt
<'_
>, item
: &Item
<'_
>) {
1933 let attrs
= tcx
.hir().attrs(item
.hir_id());
1936 if attr
.has_name(sym
::inline
) {
1941 "attribute should be applied to function or closure",
1943 .span_label(attr
.span
, "not a function or closure")
1949 fn check_mod_attrs(tcx
: TyCtxt
<'_
>, module_def_id
: LocalDefId
) {
1950 let check_attr_visitor
= &mut CheckAttrVisitor { tcx }
;
1951 tcx
.hir().visit_item_likes_in_module(module_def_id
, &mut check_attr_visitor
.as_deep_visitor());
1952 if module_def_id
.is_top_level_module() {
1953 check_attr_visitor
.check_attributes(CRATE_HIR_ID
, &DUMMY_SP
, Target
::Mod
, None
);
1954 check_invalid_crate_level_attr(tcx
, tcx
.hir().krate_attrs());
1958 pub(crate) fn provide(providers
: &mut Providers
) {
1959 *providers
= Providers { check_mod_attrs, ..*providers }
;