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-rw-r--r--compiler/rustc_passes/src/check_attr.rs2217
1 files changed, 2217 insertions, 0 deletions
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
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index 000000000..a2ac329f2
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+++ b/compiler/rustc_passes/src/check_attr.rs
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+//! This module implements some validity checks for attributes.
+//! In particular it verifies that `#[inline]` and `#[repr]` attributes are
+//! attached to items that actually support them and if there are
+//! conflicts between multiple such attributes attached to the same
+//! item.
+
+use crate::errors;
+use rustc_ast::{ast, AttrStyle, Attribute, Lit, LitKind, MetaItemKind, NestedMetaItem};
+use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::{fluent, struct_span_err, Applicability, MultiSpan};
+use rustc_expand::base::resolve_path;
+use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
+use rustc_hir as hir;
+use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID};
+use rustc_hir::intravisit::{self, Visitor};
+use rustc_hir::{self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID};
+use rustc_hir::{MethodKind, Target};
+use rustc_middle::hir::nested_filter;
+use rustc_middle::ty::query::Providers;
+use rustc_middle::ty::TyCtxt;
+use rustc_session::lint::builtin::{
+ CONFLICTING_REPR_HINTS, INVALID_DOC_ATTRIBUTES, UNUSED_ATTRIBUTES,
+};
+use rustc_session::parse::feature_err;
+use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_span::{Span, DUMMY_SP};
+use rustc_target::spec::abi::Abi;
+use std::collections::hash_map::Entry;
+
+pub(crate) fn target_from_impl_item<'tcx>(
+ tcx: TyCtxt<'tcx>,
+ impl_item: &hir::ImplItem<'_>,
+) -> Target {
+ match impl_item.kind {
+ hir::ImplItemKind::Const(..) => Target::AssocConst,
+ hir::ImplItemKind::Fn(..) => {
+ let parent_hir_id = tcx.hir().get_parent_item(impl_item.hir_id());
+ let containing_item = tcx.hir().expect_item(parent_hir_id);
+ let containing_impl_is_for_trait = match &containing_item.kind {
+ hir::ItemKind::Impl(impl_) => impl_.of_trait.is_some(),
+ _ => bug!("parent of an ImplItem must be an Impl"),
+ };
+ if containing_impl_is_for_trait {
+ Target::Method(MethodKind::Trait { body: true })
+ } else {
+ Target::Method(MethodKind::Inherent)
+ }
+ }
+ hir::ImplItemKind::TyAlias(..) => Target::AssocTy,
+ }
+}
+
+#[derive(Clone, Copy)]
+enum ItemLike<'tcx> {
+ Item(&'tcx Item<'tcx>),
+ ForeignItem,
+}
+
+struct CheckAttrVisitor<'tcx> {
+ tcx: TyCtxt<'tcx>,
+}
+
+impl CheckAttrVisitor<'_> {
+ /// Checks any attribute.
+ fn check_attributes(
+ &self,
+ hir_id: HirId,
+ span: Span,
+ target: Target,
+ item: Option<ItemLike<'_>>,
+ ) {
+ let mut doc_aliases = FxHashMap::default();
+ let mut is_valid = true;
+ let mut specified_inline = None;
+ let mut seen = FxHashMap::default();
+ let attrs = self.tcx.hir().attrs(hir_id);
+ for attr in attrs {
+ let attr_is_valid = match attr.name_or_empty() {
+ sym::inline => self.check_inline(hir_id, attr, span, target),
+ sym::no_coverage => self.check_no_coverage(hir_id, attr, span, target),
+ sym::non_exhaustive => self.check_non_exhaustive(hir_id, attr, span, target),
+ sym::marker => self.check_marker(hir_id, attr, span, target),
+ sym::rustc_must_implement_one_of => {
+ self.check_rustc_must_implement_one_of(attr, span, target)
+ }
+ sym::target_feature => self.check_target_feature(hir_id, attr, span, target),
+ sym::thread_local => self.check_thread_local(attr, span, target),
+ sym::track_caller => {
+ self.check_track_caller(hir_id, attr.span, attrs, span, target)
+ }
+ sym::doc => self.check_doc_attrs(
+ attr,
+ hir_id,
+ target,
+ &mut specified_inline,
+ &mut doc_aliases,
+ ),
+ sym::no_link => self.check_no_link(hir_id, &attr, span, target),
+ sym::export_name => self.check_export_name(hir_id, &attr, span, target),
+ sym::rustc_layout_scalar_valid_range_start
+ | sym::rustc_layout_scalar_valid_range_end => {
+ self.check_rustc_layout_scalar_valid_range(&attr, span, target)
+ }
+ sym::allow_internal_unstable => {
+ self.check_allow_internal_unstable(hir_id, &attr, span, target, &attrs)
+ }
+ sym::debugger_visualizer => self.check_debugger_visualizer(&attr, target),
+ sym::rustc_allow_const_fn_unstable => {
+ self.check_rustc_allow_const_fn_unstable(hir_id, &attr, span, target)
+ }
+ sym::rustc_std_internal_symbol => {
+ self.check_rustc_std_internal_symbol(&attr, span, target)
+ }
+ sym::naked => self.check_naked(hir_id, attr, span, target),
+ sym::rustc_legacy_const_generics => {
+ self.check_rustc_legacy_const_generics(&attr, span, target, item)
+ }
+ sym::rustc_lint_query_instability => {
+ self.check_rustc_lint_query_instability(&attr, span, target)
+ }
+ sym::rustc_lint_diagnostics => {
+ self.check_rustc_lint_diagnostics(&attr, span, target)
+ }
+ sym::rustc_lint_opt_ty => self.check_rustc_lint_opt_ty(&attr, span, target),
+ sym::rustc_lint_opt_deny_field_access => {
+ self.check_rustc_lint_opt_deny_field_access(&attr, span, target)
+ }
+ sym::rustc_clean
+ | sym::rustc_dirty
+ | sym::rustc_if_this_changed
+ | sym::rustc_then_this_would_need => self.check_rustc_dirty_clean(&attr),
+ sym::cmse_nonsecure_entry => self.check_cmse_nonsecure_entry(attr, span, target),
+ sym::const_trait => self.check_const_trait(attr, span, target),
+ sym::must_not_suspend => self.check_must_not_suspend(&attr, span, target),
+ sym::must_use => self.check_must_use(hir_id, &attr, span, target),
+ sym::rustc_pass_by_value => self.check_pass_by_value(&attr, span, target),
+ sym::rustc_allow_incoherent_impl => {
+ self.check_allow_incoherent_impl(&attr, span, target)
+ }
+ sym::rustc_has_incoherent_inherent_impls => {
+ self.check_has_incoherent_inherent_impls(&attr, span, target)
+ }
+ sym::rustc_const_unstable
+ | sym::rustc_const_stable
+ | sym::unstable
+ | sym::stable
+ | sym::rustc_allowed_through_unstable_modules
+ | sym::rustc_promotable => self.check_stability_promotable(&attr, span, target),
+ _ => true,
+ };
+ is_valid &= attr_is_valid;
+
+ // lint-only checks
+ match attr.name_or_empty() {
+ sym::cold => self.check_cold(hir_id, attr, span, target),
+ sym::link => self.check_link(hir_id, attr, span, target),
+ sym::link_name => self.check_link_name(hir_id, attr, span, target),
+ sym::link_section => self.check_link_section(hir_id, attr, span, target),
+ sym::no_mangle => self.check_no_mangle(hir_id, attr, span, target),
+ sym::deprecated => self.check_deprecated(hir_id, attr, span, target),
+ sym::macro_use | sym::macro_escape => self.check_macro_use(hir_id, attr, target),
+ sym::path => self.check_generic_attr(hir_id, attr, target, &[Target::Mod]),
+ sym::plugin_registrar => self.check_plugin_registrar(hir_id, attr, target),
+ sym::macro_export => self.check_macro_export(hir_id, attr, target),
+ sym::ignore | sym::should_panic | sym::proc_macro_derive => {
+ self.check_generic_attr(hir_id, attr, target, &[Target::Fn])
+ }
+ sym::automatically_derived => {
+ self.check_generic_attr(hir_id, attr, target, &[Target::Impl])
+ }
+ sym::no_implicit_prelude => {
+ self.check_generic_attr(hir_id, attr, target, &[Target::Mod])
+ }
+ _ => {}
+ }
+
+ let builtin = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
+
+ if hir_id != CRATE_HIR_ID {
+ if let Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) =
+ attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name))
+ {
+ match attr.style {
+ ast::AttrStyle::Outer => self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::OuterCrateLevelAttr,
+ ),
+ ast::AttrStyle::Inner => self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::InnerCrateLevelAttr,
+ ),
+ }
+ }
+ }
+
+ if let Some(BuiltinAttribute { duplicates, .. }) = builtin {
+ check_duplicates(self.tcx, attr, hir_id, *duplicates, &mut seen);
+ }
+
+ self.check_unused_attribute(hir_id, attr)
+ }
+
+ if !is_valid {
+ return;
+ }
+
+ // FIXME(@lcnr): this doesn't belong here.
+ if matches!(target, Target::Closure | Target::Fn | Target::Method(_) | Target::ForeignFn) {
+ self.tcx.ensure().codegen_fn_attrs(self.tcx.hir().local_def_id(hir_id));
+ }
+
+ self.check_repr(attrs, span, target, item, hir_id);
+ self.check_used(attrs, target);
+ }
+
+ fn inline_attr_str_error_with_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::IgnoredAttrWithMacro { sym },
+ );
+ }
+
+ fn inline_attr_str_error_without_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::IgnoredAttr { sym },
+ );
+ }
+
+ /// Checks if an `#[inline]` is applied to a function or a closure. Returns `true` if valid.
+ fn check_inline(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::Fn
+ | Target::Closure
+ | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
+ Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::IgnoredInlineAttrFnProto,
+ );
+ true
+ }
+ // FIXME(#65833): We permit associated consts to have an `#[inline]` attribute with
+ // just a lint, because we previously erroneously allowed it and some crates used it
+ // accidentally, to to be compatible with crates depending on them, we can't throw an
+ // error here.
+ Target::AssocConst => {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::IgnoredInlineAttrConstants,
+ );
+ true
+ }
+ // FIXME(#80564): Same for fields, arms, and macro defs
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "inline");
+ true
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::InlineNotFnOrClosure {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ /// Checks if a `#[no_coverage]` is applied directly to a function
+ fn check_no_coverage(
+ &self,
+ hir_id: HirId,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ // no_coverage on function is fine
+ Target::Fn
+ | Target::Closure
+ | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
+
+ // function prototypes can't be covered
+ Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::IgnoredNoCoverageFnProto,
+ );
+ true
+ }
+
+ Target::Mod | Target::ForeignMod | Target::Impl | Target::Trait => {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::IgnoredNoCoveragePropagate,
+ );
+ true
+ }
+
+ Target::Expression | Target::Statement | Target::Arm => {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::IgnoredNoCoverageFnDefn,
+ );
+ true
+ }
+
+ _ => {
+ self.tcx.sess.emit_err(errors::IgnoredNoCoverageNotCoverable {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ fn check_generic_attr(
+ &self,
+ hir_id: HirId,
+ attr: &Attribute,
+ target: Target,
+ allowed_targets: &[Target],
+ ) {
+ if !allowed_targets.iter().any(|t| t == &target) {
+ let name = attr.name_or_empty();
+ let mut i = allowed_targets.iter();
+ // Pluralize
+ let b = i.next().map_or_else(String::new, |t| t.to_string() + "s");
+ let supported_names = i.enumerate().fold(b, |mut b, (i, allowed_target)| {
+ if allowed_targets.len() > 2 && i == allowed_targets.len() - 2 {
+ b.push_str(", and ");
+ } else if allowed_targets.len() == 2 && i == allowed_targets.len() - 2 {
+ b.push_str(" and ");
+ } else {
+ b.push_str(", ");
+ }
+ // Pluralize
+ b.push_str(&(allowed_target.to_string() + "s"));
+ b
+ });
+ self.tcx.struct_span_lint_hir(UNUSED_ATTRIBUTES, hir_id, attr.span, |lint| {
+ lint.build(&format!("`#[{name}]` only has an effect on {}", supported_names))
+ .emit();
+ });
+ }
+ }
+
+ /// Checks if `#[naked]` is applied to a function definition.
+ fn check_naked(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::Fn
+ | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[allow_internal_unstable]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "naked");
+ true
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ /// Checks if `#[cmse_nonsecure_entry]` is applied to a function definition.
+ fn check_cmse_nonsecure_entry(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::Fn
+ | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
+ _ => {
+ self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ /// Checks if a `#[track_caller]` is applied to a non-naked function. Returns `true` if valid.
+ fn check_track_caller(
+ &self,
+ hir_id: HirId,
+ attr_span: Span,
+ attrs: &[Attribute],
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ _ if attrs.iter().any(|attr| attr.has_name(sym::naked)) => {
+ self.tcx.sess.emit_err(errors::NakedTrackedCaller { attr_span });
+ false
+ }
+ Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => true,
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[track_caller]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ for attr in attrs {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "track_caller");
+ }
+ true
+ }
+ _ => {
+ self.tcx
+ .sess
+ .emit_err(errors::TrackedCallerWrongLocation { attr_span, defn_span: span });
+ false
+ }
+ }
+ }
+
+ /// Checks if the `#[non_exhaustive]` attribute on an `item` is valid. Returns `true` if valid.
+ fn check_non_exhaustive(
+ &self,
+ hir_id: HirId,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ Target::Struct | Target::Enum | Target::Variant => true,
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[non_exhaustive]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "non_exhaustive");
+ true
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::NonExhaustiveWrongLocation {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ /// Checks if the `#[marker]` attribute on an `item` is valid. Returns `true` if valid.
+ fn check_marker(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::Trait => true,
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[marker]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "marker");
+ true
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ /// Checks if the `#[rustc_must_implement_one_of]` attribute on a `target` is valid. Returns `true` if valid.
+ fn check_rustc_must_implement_one_of(
+ &self,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ Target::Trait => true,
+ _ => {
+ self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToTrait {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ /// Checks if the `#[target_feature]` attribute on `item` is valid. Returns `true` if valid.
+ fn check_target_feature(
+ &self,
+ hir_id: HirId,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ Target::Fn
+ | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => true,
+ // FIXME: #[target_feature] was previously erroneously allowed on statements and some
+ // crates used this, so only emit a warning.
+ Target::Statement => {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::TargetFeatureOnStatement,
+ );
+ true
+ }
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[target_feature]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "target_feature");
+ true
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ /// Checks if the `#[thread_local]` attribute on `item` is valid. Returns `true` if valid.
+ fn check_thread_local(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::ForeignStatic | Target::Static => true,
+ _ => {
+ self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToStatic {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ }
+ }
+ }
+
+ fn doc_attr_str_error(&self, meta: &NestedMetaItem, attr_name: &str) {
+ self.tcx.sess.emit_err(errors::DocExpectStr { attr_span: meta.span(), attr_name });
+ }
+
+ fn check_doc_alias_value(
+ &self,
+ meta: &NestedMetaItem,
+ doc_alias: Symbol,
+ hir_id: HirId,
+ target: Target,
+ is_list: bool,
+ aliases: &mut FxHashMap<String, Span>,
+ ) -> bool {
+ let tcx = self.tcx;
+ let span = meta.name_value_literal_span().unwrap_or_else(|| meta.span());
+ let attr_str =
+ &format!("`#[doc(alias{})]`", if is_list { "(\"...\")" } else { " = \"...\"" });
+ if doc_alias == kw::Empty {
+ tcx.sess.emit_err(errors::DocAliasEmpty { span, attr_str });
+ return false;
+ }
+
+ let doc_alias_str = doc_alias.as_str();
+ if let Some(c) = doc_alias_str
+ .chars()
+ .find(|&c| c == '"' || c == '\'' || (c.is_whitespace() && c != ' '))
+ {
+ tcx.sess.emit_err(errors::DocAliasBadChar { span, attr_str, char_: c });
+ return false;
+ }
+ if doc_alias_str.starts_with(' ') || doc_alias_str.ends_with(' ') {
+ tcx.sess.emit_err(errors::DocAliasStartEnd { span, attr_str });
+ return false;
+ }
+
+ let span = meta.span();
+ if let Some(location) = match target {
+ Target::AssocTy => {
+ let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
+ let containing_item = self.tcx.hir().expect_item(parent_hir_id);
+ if Target::from_item(containing_item) == Target::Impl {
+ Some("type alias in implementation block")
+ } else {
+ None
+ }
+ }
+ Target::AssocConst => {
+ let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
+ let containing_item = self.tcx.hir().expect_item(parent_hir_id);
+ // We can't link to trait impl's consts.
+ let err = "associated constant in trait implementation block";
+ match containing_item.kind {
+ ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => Some(err),
+ _ => None,
+ }
+ }
+ // we check the validity of params elsewhere
+ Target::Param => return false,
+ Target::Expression
+ | Target::Statement
+ | Target::Arm
+ | Target::ForeignMod
+ | Target::Closure
+ | Target::Impl => Some(target.name()),
+ Target::ExternCrate
+ | Target::Use
+ | Target::Static
+ | Target::Const
+ | Target::Fn
+ | Target::Mod
+ | Target::GlobalAsm
+ | Target::TyAlias
+ | Target::OpaqueTy
+ | Target::Enum
+ | Target::Variant
+ | Target::Struct
+ | Target::Field
+ | Target::Union
+ | Target::Trait
+ | Target::TraitAlias
+ | Target::Method(..)
+ | Target::ForeignFn
+ | Target::ForeignStatic
+ | Target::ForeignTy
+ | Target::GenericParam(..)
+ | Target::MacroDef => None,
+ } {
+ tcx.sess.emit_err(errors::DocAliasBadLocation { span, attr_str, location });
+ return false;
+ }
+ let item_name = self.tcx.hir().name(hir_id);
+ if item_name == doc_alias {
+ tcx.sess.emit_err(errors::DocAliasNotAnAlias { span, attr_str });
+ return false;
+ }
+ if let Err(entry) = aliases.try_insert(doc_alias_str.to_owned(), span) {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ span,
+ errors::DocAliasDuplicated { first_defn: *entry.entry.get() },
+ );
+ }
+ true
+ }
+
+ fn check_doc_alias(
+ &self,
+ meta: &NestedMetaItem,
+ hir_id: HirId,
+ target: Target,
+ aliases: &mut FxHashMap<String, Span>,
+ ) -> bool {
+ if let Some(values) = meta.meta_item_list() {
+ let mut errors = 0;
+ for v in values {
+ match v.literal() {
+ Some(l) => match l.kind {
+ LitKind::Str(s, _) => {
+ if !self.check_doc_alias_value(v, s, hir_id, target, true, aliases) {
+ errors += 1;
+ }
+ }
+ _ => {
+ self.tcx
+ .sess
+ .emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
+ errors += 1;
+ }
+ },
+ None => {
+ self.tcx.sess.emit_err(errors::DocAliasNotStringLiteral { span: v.span() });
+ errors += 1;
+ }
+ }
+ }
+ errors == 0
+ } else if let Some(doc_alias) = meta.value_str() {
+ self.check_doc_alias_value(meta, doc_alias, hir_id, target, false, aliases)
+ } else {
+ self.tcx.sess.emit_err(errors::DocAliasMalformed { span: meta.span() });
+ false
+ }
+ }
+
+ fn check_doc_keyword(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
+ let doc_keyword = meta.value_str().unwrap_or(kw::Empty);
+ if doc_keyword == kw::Empty {
+ self.doc_attr_str_error(meta, "keyword");
+ return false;
+ }
+ match self.tcx.hir().find(hir_id).and_then(|node| match node {
+ hir::Node::Item(item) => Some(&item.kind),
+ _ => None,
+ }) {
+ Some(ItemKind::Mod(ref module)) => {
+ if !module.item_ids.is_empty() {
+ self.tcx.sess.emit_err(errors::DocKeywordEmptyMod { span: meta.span() });
+ return false;
+ }
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::DocKeywordNotMod { span: meta.span() });
+ return false;
+ }
+ }
+ if !rustc_lexer::is_ident(doc_keyword.as_str()) {
+ self.tcx.sess.emit_err(errors::DocKeywordInvalidIdent {
+ span: meta.name_value_literal_span().unwrap_or_else(|| meta.span()),
+ doc_keyword,
+ });
+ return false;
+ }
+ true
+ }
+
+ fn check_doc_fake_variadic(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
+ match self.tcx.hir().find(hir_id).and_then(|node| match node {
+ hir::Node::Item(item) => Some(&item.kind),
+ _ => None,
+ }) {
+ Some(ItemKind::Impl(ref i)) => {
+ let is_valid = matches!(&i.self_ty.kind, hir::TyKind::Tup([_]))
+ || if let hir::TyKind::BareFn(bare_fn_ty) = &i.self_ty.kind {
+ bare_fn_ty.decl.inputs.len() == 1
+ } else {
+ false
+ };
+ if !is_valid {
+ self.tcx.sess.emit_err(errors::DocFakeVariadicNotValid { span: meta.span() });
+ return false;
+ }
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::DocKeywordOnlyImpl { span: meta.span() });
+ return false;
+ }
+ }
+ true
+ }
+
+ /// Checks `#[doc(inline)]`/`#[doc(no_inline)]` attributes. Returns `true` if valid.
+ ///
+ /// A doc inlining attribute is invalid if it is applied to a non-`use` item, or
+ /// if there are conflicting attributes for one item.
+ ///
+ /// `specified_inline` is used to keep track of whether we have
+ /// already seen an inlining attribute for this item.
+ /// If so, `specified_inline` holds the value and the span of
+ /// the first `inline`/`no_inline` attribute.
+ fn check_doc_inline(
+ &self,
+ attr: &Attribute,
+ meta: &NestedMetaItem,
+ hir_id: HirId,
+ target: Target,
+ specified_inline: &mut Option<(bool, Span)>,
+ ) -> bool {
+ if target == Target::Use || target == Target::ExternCrate {
+ let do_inline = meta.name_or_empty() == sym::inline;
+ if let Some((prev_inline, prev_span)) = *specified_inline {
+ if do_inline != prev_inline {
+ let mut spans = MultiSpan::from_spans(vec![prev_span, meta.span()]);
+ spans.push_span_label(prev_span, fluent::passes::doc_inline_conflict_first);
+ spans.push_span_label(meta.span(), fluent::passes::doc_inline_conflict_second);
+ self.tcx.sess.emit_err(errors::DocKeywordConflict { spans });
+ return false;
+ }
+ true
+ } else {
+ *specified_inline = Some((do_inline, meta.span()));
+ true
+ }
+ } else {
+ self.tcx.emit_spanned_lint(
+ INVALID_DOC_ATTRIBUTES,
+ hir_id,
+ meta.span(),
+ errors::DocInlineOnlyUse {
+ attr_span: meta.span(),
+ item_span: (attr.style == AttrStyle::Outer)
+ .then(|| self.tcx.hir().span(hir_id)),
+ },
+ );
+ false
+ }
+ }
+
+ /// Checks that an attribute is *not* used at the crate level. Returns `true` if valid.
+ fn check_attr_not_crate_level(
+ &self,
+ meta: &NestedMetaItem,
+ hir_id: HirId,
+ attr_name: &str,
+ ) -> bool {
+ if CRATE_HIR_ID == hir_id {
+ self.tcx.sess.emit_err(errors::DocAttrNotCrateLevel { span: meta.span(), attr_name });
+ return false;
+ }
+ true
+ }
+
+ /// Checks that an attribute is used at the crate level. Returns `true` if valid.
+ fn check_attr_crate_level(
+ &self,
+ attr: &Attribute,
+ meta: &NestedMetaItem,
+ hir_id: HirId,
+ ) -> bool {
+ if hir_id != CRATE_HIR_ID {
+ self.tcx.struct_span_lint_hir(INVALID_DOC_ATTRIBUTES, hir_id, meta.span(), |lint| {
+ let mut err = lint.build(fluent::passes::attr_crate_level);
+ if attr.style == AttrStyle::Outer
+ && self.tcx.hir().get_parent_item(hir_id) == CRATE_DEF_ID
+ {
+ if let Ok(mut src) = self.tcx.sess.source_map().span_to_snippet(attr.span) {
+ src.insert(1, '!');
+ err.span_suggestion_verbose(
+ attr.span,
+ fluent::passes::suggestion,
+ src,
+ Applicability::MaybeIncorrect,
+ );
+ } else {
+ err.span_help(attr.span, fluent::passes::help);
+ }
+ }
+ err.note(fluent::passes::note).emit();
+ });
+ return false;
+ }
+ true
+ }
+
+ /// Checks that `doc(test(...))` attribute contains only valid attributes. Returns `true` if
+ /// valid.
+ fn check_test_attr(&self, meta: &NestedMetaItem, hir_id: HirId) -> bool {
+ let mut is_valid = true;
+ if let Some(metas) = meta.meta_item_list() {
+ for i_meta in metas {
+ match i_meta.name_or_empty() {
+ sym::attr | sym::no_crate_inject => {}
+ _ => {
+ self.tcx.emit_spanned_lint(
+ INVALID_DOC_ATTRIBUTES,
+ hir_id,
+ i_meta.span(),
+ errors::DocTestUnknown {
+ path: rustc_ast_pretty::pprust::path_to_string(
+ &i_meta.meta_item().unwrap().path,
+ ),
+ },
+ );
+ is_valid = false;
+ }
+ }
+ }
+ } else {
+ self.tcx.emit_spanned_lint(
+ INVALID_DOC_ATTRIBUTES,
+ hir_id,
+ meta.span(),
+ errors::DocTestTakesList,
+ );
+ is_valid = false;
+ }
+ is_valid
+ }
+
+ /// Runs various checks on `#[doc]` attributes. Returns `true` if valid.
+ ///
+ /// `specified_inline` should be initialized to `None` and kept for the scope
+ /// of one item. Read the documentation of [`check_doc_inline`] for more information.
+ ///
+ /// [`check_doc_inline`]: Self::check_doc_inline
+ fn check_doc_attrs(
+ &self,
+ attr: &Attribute,
+ hir_id: HirId,
+ target: Target,
+ specified_inline: &mut Option<(bool, Span)>,
+ aliases: &mut FxHashMap<String, Span>,
+ ) -> bool {
+ let mut is_valid = true;
+
+ if let Some(mi) = attr.meta() && let Some(list) = mi.meta_item_list() {
+ for meta in list {
+ if let Some(i_meta) = meta.meta_item() {
+ match i_meta.name_or_empty() {
+ sym::alias
+ if !self.check_attr_not_crate_level(meta, hir_id, "alias")
+ || !self.check_doc_alias(meta, hir_id, target, aliases) =>
+ {
+ is_valid = false
+ }
+
+ sym::keyword
+ if !self.check_attr_not_crate_level(meta, hir_id, "keyword")
+ || !self.check_doc_keyword(meta, hir_id) =>
+ {
+ is_valid = false
+ }
+
+ sym::fake_variadic
+ if !self.check_attr_not_crate_level(meta, hir_id, "fake_variadic")
+ || !self.check_doc_fake_variadic(meta, hir_id) =>
+ {
+ is_valid = false
+ }
+
+ sym::html_favicon_url
+ | sym::html_logo_url
+ | sym::html_playground_url
+ | sym::issue_tracker_base_url
+ | sym::html_root_url
+ | sym::html_no_source
+ | sym::test
+ if !self.check_attr_crate_level(attr, meta, hir_id) =>
+ {
+ is_valid = false;
+ }
+
+ sym::inline | sym::no_inline
+ if !self.check_doc_inline(
+ attr,
+ meta,
+ hir_id,
+ target,
+ specified_inline,
+ ) =>
+ {
+ is_valid = false;
+ }
+
+ // no_default_passes: deprecated
+ // passes: deprecated
+ // plugins: removed, but rustdoc warns about it itself
+ sym::alias
+ | sym::cfg
+ | sym::cfg_hide
+ | sym::hidden
+ | sym::html_favicon_url
+ | sym::html_logo_url
+ | sym::html_no_source
+ | sym::html_playground_url
+ | sym::html_root_url
+ | sym::inline
+ | sym::issue_tracker_base_url
+ | sym::keyword
+ | sym::masked
+ | sym::no_default_passes
+ | sym::no_inline
+ | sym::notable_trait
+ | sym::passes
+ | sym::plugins
+ | sym::fake_variadic => {}
+
+ sym::test => {
+ if !self.check_test_attr(meta, hir_id) {
+ is_valid = false;
+ }
+ }
+
+ sym::primitive => {
+ if !self.tcx.features().rustdoc_internals {
+ self.tcx.emit_spanned_lint(
+ INVALID_DOC_ATTRIBUTES,
+ hir_id,
+ i_meta.span,
+ errors::DocPrimitive,
+ );
+ }
+ }
+
+ _ => {
+ let path = rustc_ast_pretty::pprust::path_to_string(&i_meta.path);
+ if i_meta.has_name(sym::spotlight) {
+ self.tcx.emit_spanned_lint(
+ INVALID_DOC_ATTRIBUTES,
+ hir_id,
+ i_meta.span,
+ errors::DocTestUnknownSpotlight {
+ path,
+ span: i_meta.span
+ }
+ );
+ } else if i_meta.has_name(sym::include) &&
+ let Some(value) = i_meta.value_str() {
+ let applicability = if list.len() == 1 {
+ Applicability::MachineApplicable
+ } else {
+ Applicability::MaybeIncorrect
+ };
+ // If there are multiple attributes, the suggestion would suggest
+ // deleting all of them, which is incorrect.
+ self.tcx.emit_spanned_lint(
+ INVALID_DOC_ATTRIBUTES,
+ hir_id,
+ i_meta.span,
+ errors::DocTestUnknownInclude {
+ path,
+ value: value.to_string(),
+ inner: (attr.style == AttrStyle::Inner)
+ .then_some("!")
+ .unwrap_or(""),
+ sugg: (attr.meta().unwrap().span, applicability),
+ }
+ );
+ } else {
+ self.tcx.emit_spanned_lint(
+ INVALID_DOC_ATTRIBUTES,
+ hir_id,
+ i_meta.span,
+ errors::DocTestUnknownAny { path }
+ );
+ }
+ is_valid = false;
+ }
+ }
+ } else {
+ self.tcx.emit_spanned_lint(
+ INVALID_DOC_ATTRIBUTES,
+ hir_id,
+ meta.span(),
+ errors::DocInvalid,
+ );
+ is_valid = false;
+ }
+ }
+ }
+
+ is_valid
+ }
+
+ /// Warns against some misuses of `#[pass_by_value]`
+ fn check_pass_by_value(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::Struct | Target::Enum | Target::TyAlias => true,
+ _ => {
+ self.tcx.sess.emit_err(errors::PassByValue { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ fn check_allow_incoherent_impl(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::Method(MethodKind::Inherent) => true,
+ _ => {
+ self.tcx.sess.emit_err(errors::AllowIncoherentImpl { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ fn check_has_incoherent_inherent_impls(
+ &self,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ Target::Trait | Target::Struct | Target::Enum | Target::Union | Target::ForeignTy => {
+ true
+ }
+ _ => {
+ self.tcx
+ .sess
+ .emit_err(errors::HasIncoherentInherentImpl { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ /// Warns against some misuses of `#[must_use]`
+ fn check_must_use(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
+ let node = self.tcx.hir().get(hir_id);
+ if let Some(kind) = node.fn_kind() && let rustc_hir::IsAsync::Async = kind.asyncness() {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::MustUseAsync { span }
+ );
+ }
+
+ if !matches!(
+ target,
+ Target::Fn
+ | Target::Enum
+ | Target::Struct
+ | Target::Union
+ | Target::Method(_)
+ | Target::ForeignFn
+ // `impl Trait` in return position can trip
+ // `unused_must_use` if `Trait` is marked as
+ // `#[must_use]`
+ | Target::Trait
+ ) {
+ let article = match target {
+ Target::ExternCrate
+ | Target::OpaqueTy
+ | Target::Enum
+ | Target::Impl
+ | Target::Expression
+ | Target::Arm
+ | Target::AssocConst
+ | Target::AssocTy => "an",
+ _ => "a",
+ };
+
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::MustUseNoEffect { article, target },
+ );
+ }
+
+ // For now, its always valid
+ true
+ }
+
+ /// Checks if `#[must_not_suspend]` is applied to a function. Returns `true` if valid.
+ fn check_must_not_suspend(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::Struct | Target::Enum | Target::Union | Target::Trait => true,
+ _ => {
+ self.tcx.sess.emit_err(errors::MustNotSuspend { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ /// Checks if `#[cold]` is applied to a non-function. Returns `true` if valid.
+ fn check_cold(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
+ match target {
+ Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => {}
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[cold]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "cold");
+ }
+ _ => {
+ // FIXME: #[cold] was previously allowed on non-functions and some crates used
+ // this, so only emit a warning.
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::Cold { span },
+ );
+ }
+ }
+ }
+
+ /// Checks if `#[link]` is applied to an item other than a foreign module.
+ fn check_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
+ if target == Target::ForeignMod
+ && let hir::Node::Item(item) = self.tcx.hir().get(hir_id)
+ && let Item { kind: ItemKind::ForeignMod { abi, .. }, .. } = item
+ && !matches!(abi, Abi::Rust | Abi::RustIntrinsic | Abi::PlatformIntrinsic)
+ {
+ return;
+ }
+
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::Link { span: (target != Target::ForeignMod).then_some(span) },
+ );
+ }
+
+ /// Checks if `#[link_name]` is applied to an item other than a foreign function or static.
+ fn check_link_name(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
+ match target {
+ Target::ForeignFn | Target::ForeignStatic => {}
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[link_name]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_name");
+ }
+ _ => {
+ // FIXME: #[cold] was previously allowed on non-functions/statics and some crates
+ // used this, so only emit a warning.
+ let attr_span = matches!(target, Target::ForeignMod).then_some(attr.span);
+ if let Some(s) = attr.value_str() {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::LinkName { span, attr_span, value: s.as_str() },
+ );
+ } else {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::LinkName { span, attr_span, value: "..." },
+ );
+ };
+ }
+ }
+ }
+
+ /// Checks if `#[no_link]` is applied to an `extern crate`. Returns `true` if valid.
+ fn check_no_link(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::ExternCrate => true,
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[no_link]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_link");
+ true
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::NoLink { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ fn is_impl_item(&self, hir_id: HirId) -> bool {
+ matches!(self.tcx.hir().get(hir_id), hir::Node::ImplItem(..))
+ }
+
+ /// Checks if `#[export_name]` is applied to a function or static. Returns `true` if valid.
+ fn check_export_name(
+ &self,
+ hir_id: HirId,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ Target::Static | Target::Fn => true,
+ Target::Method(..) if self.is_impl_item(hir_id) => true,
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[export_name]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "export_name");
+ true
+ }
+ _ => {
+ self.tcx.sess.emit_err(errors::ExportName { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ fn check_rustc_layout_scalar_valid_range(
+ &self,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ if target != Target::Struct {
+ self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeNotStruct {
+ attr_span: attr.span,
+ span,
+ });
+ return false;
+ }
+
+ let Some(list) = attr.meta_item_list() else {
+ return false;
+ };
+
+ if matches!(&list[..], &[NestedMetaItem::Literal(Lit { kind: LitKind::Int(..), .. })]) {
+ true
+ } else {
+ self.tcx.sess.emit_err(errors::RustcLayoutScalarValidRangeArg { attr_span: attr.span });
+ false
+ }
+ }
+
+ /// Checks if `#[rustc_legacy_const_generics]` is applied to a function and has a valid argument.
+ fn check_rustc_legacy_const_generics(
+ &self,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ item: Option<ItemLike<'_>>,
+ ) -> bool {
+ let is_function = matches!(target, Target::Fn);
+ if !is_function {
+ self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ return false;
+ }
+
+ let Some(list) = attr.meta_item_list() else {
+ // The attribute form is validated on AST.
+ return false;
+ };
+
+ let Some(ItemLike::Item(Item {
+ kind: ItemKind::Fn(FnSig { decl, .. }, generics, _),
+ ..
+ })) = item else {
+ bug!("should be a function item");
+ };
+
+ for param in generics.params {
+ match param.kind {
+ hir::GenericParamKind::Const { .. } => {}
+ _ => {
+ self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsOnly {
+ attr_span: attr.span,
+ param_span: param.span,
+ });
+ return false;
+ }
+ }
+ }
+
+ if list.len() != generics.params.len() {
+ self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndex {
+ attr_span: attr.span,
+ generics_span: generics.span,
+ });
+ return false;
+ }
+
+ let arg_count = decl.inputs.len() as u128 + generics.params.len() as u128;
+ let mut invalid_args = vec![];
+ for meta in list {
+ if let Some(LitKind::Int(val, _)) = meta.literal().map(|lit| &lit.kind) {
+ if *val >= arg_count {
+ let span = meta.span();
+ self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexExceed {
+ span,
+ arg_count: arg_count as usize,
+ });
+ return false;
+ }
+ } else {
+ invalid_args.push(meta.span());
+ }
+ }
+
+ if !invalid_args.is_empty() {
+ self.tcx.sess.emit_err(errors::RustcLegacyConstGenericsIndexNegative { invalid_args });
+ false
+ } else {
+ true
+ }
+ }
+
+ /// Helper function for checking that the provided attribute is only applied to a function or
+ /// method.
+ fn check_applied_to_fn_or_method(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+ let is_function = matches!(target, Target::Fn | Target::Method(..));
+ if !is_function {
+ self.tcx.sess.emit_err(errors::AttrShouldBeAppliedToFn {
+ attr_span: attr.span,
+ defn_span: span,
+ });
+ false
+ } else {
+ true
+ }
+ }
+
+ /// Checks that the `#[rustc_lint_query_instability]` attribute is only applied to a function
+ /// or method.
+ fn check_rustc_lint_query_instability(
+ &self,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ self.check_applied_to_fn_or_method(attr, span, target)
+ }
+
+ /// Checks that the `#[rustc_lint_diagnostics]` attribute is only applied to a function or
+ /// method.
+ fn check_rustc_lint_diagnostics(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+ self.check_applied_to_fn_or_method(attr, span, target)
+ }
+
+ /// Checks that the `#[rustc_lint_opt_ty]` attribute is only applied to a struct.
+ fn check_rustc_lint_opt_ty(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+ match target {
+ Target::Struct => true,
+ _ => {
+ self.tcx.sess.emit_err(errors::RustcLintOptTy { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ /// Checks that the `#[rustc_lint_opt_deny_field_access]` attribute is only applied to a field.
+ fn check_rustc_lint_opt_deny_field_access(
+ &self,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ Target::Field => true,
+ _ => {
+ self.tcx
+ .sess
+ .emit_err(errors::RustcLintOptDenyFieldAccess { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ /// Checks that the dep-graph debugging attributes are only present when the query-dep-graph
+ /// option is passed to the compiler.
+ fn check_rustc_dirty_clean(&self, attr: &Attribute) -> bool {
+ if self.tcx.sess.opts.unstable_opts.query_dep_graph {
+ true
+ } else {
+ self.tcx.sess.emit_err(errors::RustcDirtyClean { span: attr.span });
+ false
+ }
+ }
+
+ /// Checks if `#[link_section]` is applied to a function or static.
+ fn check_link_section(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
+ match target {
+ Target::Static | Target::Fn | Target::Method(..) => {}
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[link_section]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "link_section");
+ }
+ _ => {
+ // FIXME: #[link_section] was previously allowed on non-functions/statics and some
+ // crates used this, so only emit a warning.
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::LinkSection { span },
+ );
+ }
+ }
+ }
+
+ /// Checks if `#[no_mangle]` is applied to a function or static.
+ fn check_no_mangle(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
+ match target {
+ Target::Static | Target::Fn => {}
+ Target::Method(..) if self.is_impl_item(hir_id) => {}
+ // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
+ // `#[no_mangle]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "no_mangle");
+ }
+ // FIXME: #[no_mangle] was previously allowed on non-functions/statics, this should be an error
+ // The error should specify that the item that is wrong is specifically a *foreign* fn/static
+ // otherwise the error seems odd
+ Target::ForeignFn | Target::ForeignStatic => {
+ let foreign_item_kind = match target {
+ Target::ForeignFn => "function",
+ Target::ForeignStatic => "static",
+ _ => unreachable!(),
+ };
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::NoMangleForeign { span, attr_span: attr.span, foreign_item_kind },
+ );
+ }
+ _ => {
+ // FIXME: #[no_mangle] was previously allowed on non-functions/statics and some
+ // crates used this, so only emit a warning.
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::NoMangle { span },
+ );
+ }
+ }
+ }
+
+ /// Checks if the `#[repr]` attributes on `item` are valid.
+ fn check_repr(
+ &self,
+ attrs: &[Attribute],
+ span: Span,
+ target: Target,
+ item: Option<ItemLike<'_>>,
+ hir_id: HirId,
+ ) {
+ // Extract the names of all repr hints, e.g., [foo, bar, align] for:
+ // ```
+ // #[repr(foo)]
+ // #[repr(bar, align(8))]
+ // ```
+ let hints: Vec<_> = attrs
+ .iter()
+ .filter(|attr| attr.has_name(sym::repr))
+ .filter_map(|attr| attr.meta_item_list())
+ .flatten()
+ .collect();
+
+ let mut int_reprs = 0;
+ let mut is_c = false;
+ let mut is_simd = false;
+ let mut is_transparent = false;
+
+ for hint in &hints {
+ if !hint.is_meta_item() {
+ self.tcx.sess.emit_err(errors::ReprIdent { span: hint.span() });
+ continue;
+ }
+
+ let (article, allowed_targets) = match hint.name_or_empty() {
+ sym::C => {
+ is_c = true;
+ match target {
+ Target::Struct | Target::Union | Target::Enum => continue,
+ _ => ("a", "struct, enum, or union"),
+ }
+ }
+ sym::align => {
+ if let (Target::Fn, false) = (target, self.tcx.features().fn_align) {
+ feature_err(
+ &self.tcx.sess.parse_sess,
+ sym::fn_align,
+ hint.span(),
+ "`repr(align)` attributes on functions are unstable",
+ )
+ .emit();
+ }
+
+ match target {
+ Target::Struct | Target::Union | Target::Enum | Target::Fn => continue,
+ _ => ("a", "struct, enum, function, or union"),
+ }
+ }
+ sym::packed => {
+ if target != Target::Struct && target != Target::Union {
+ ("a", "struct or union")
+ } else {
+ continue;
+ }
+ }
+ sym::simd => {
+ is_simd = true;
+ if target != Target::Struct {
+ ("a", "struct")
+ } else {
+ continue;
+ }
+ }
+ sym::transparent => {
+ is_transparent = true;
+ match target {
+ Target::Struct | Target::Union | Target::Enum => continue,
+ _ => ("a", "struct, enum, or union"),
+ }
+ }
+ sym::i8
+ | sym::u8
+ | sym::i16
+ | sym::u16
+ | sym::i32
+ | sym::u32
+ | sym::i64
+ | sym::u64
+ | sym::i128
+ | sym::u128
+ | sym::isize
+ | sym::usize => {
+ int_reprs += 1;
+ if target != Target::Enum {
+ ("an", "enum")
+ } else {
+ continue;
+ }
+ }
+ _ => {
+ struct_span_err!(
+ self.tcx.sess,
+ hint.span(),
+ E0552,
+ "unrecognized representation hint"
+ )
+ .emit();
+
+ continue;
+ }
+ };
+
+ struct_span_err!(
+ self.tcx.sess,
+ hint.span(),
+ E0517,
+ "{}",
+ &format!("attribute should be applied to {article} {allowed_targets}")
+ )
+ .span_label(span, &format!("not {article} {allowed_targets}"))
+ .emit();
+ }
+
+ // Just point at all repr hints if there are any incompatibilities.
+ // This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
+ let hint_spans = hints.iter().map(|hint| hint.span());
+
+ // Error on repr(transparent, <anything else>).
+ if is_transparent && hints.len() > 1 {
+ let hint_spans: Vec<_> = hint_spans.clone().collect();
+ struct_span_err!(
+ self.tcx.sess,
+ hint_spans,
+ E0692,
+ "transparent {} cannot have other repr hints",
+ target
+ )
+ .emit();
+ }
+ // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
+ if (int_reprs > 1)
+ || (is_simd && is_c)
+ || (int_reprs == 1
+ && is_c
+ && item.map_or(false, |item| {
+ if let ItemLike::Item(item) = item {
+ return is_c_like_enum(item);
+ }
+ return false;
+ }))
+ {
+ self.tcx.emit_spanned_lint(
+ CONFLICTING_REPR_HINTS,
+ hir_id,
+ hint_spans.collect::<Vec<Span>>(),
+ errors::ReprConflicting,
+ );
+ }
+ }
+
+ fn check_used(&self, attrs: &[Attribute], target: Target) {
+ let mut used_linker_span = None;
+ let mut used_compiler_span = None;
+ for attr in attrs.iter().filter(|attr| attr.has_name(sym::used)) {
+ if target != Target::Static {
+ self.tcx.sess.emit_err(errors::UsedStatic { span: attr.span });
+ }
+ let inner = attr.meta_item_list();
+ match inner.as_deref() {
+ Some([item]) if item.has_name(sym::linker) => {
+ if used_linker_span.is_none() {
+ used_linker_span = Some(attr.span);
+ }
+ }
+ Some([item]) if item.has_name(sym::compiler) => {
+ if used_compiler_span.is_none() {
+ used_compiler_span = Some(attr.span);
+ }
+ }
+ Some(_) => {
+ // This error case is handled in rustc_typeck::collect.
+ }
+ None => {
+ // Default case (compiler) when arg isn't defined.
+ if used_compiler_span.is_none() {
+ used_compiler_span = Some(attr.span);
+ }
+ }
+ }
+ }
+ if let (Some(linker_span), Some(compiler_span)) = (used_linker_span, used_compiler_span) {
+ self.tcx
+ .sess
+ .emit_err(errors::UsedCompilerLinker { spans: vec![linker_span, compiler_span] });
+ }
+ }
+
+ /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
+ /// (Allows proc_macro functions)
+ fn check_allow_internal_unstable(
+ &self,
+ hir_id: HirId,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ attrs: &[Attribute],
+ ) -> bool {
+ debug!("Checking target: {:?}", target);
+ match target {
+ Target::Fn => {
+ for attr in attrs {
+ if self.tcx.sess.is_proc_macro_attr(attr) {
+ debug!("Is proc macro attr");
+ return true;
+ }
+ }
+ debug!("Is not proc macro attr");
+ false
+ }
+ Target::MacroDef => true,
+ // FIXME(#80564): We permit struct fields and match arms to have an
+ // `#[allow_internal_unstable]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm => {
+ self.inline_attr_str_error_without_macro_def(
+ hir_id,
+ attr,
+ "allow_internal_unstable",
+ );
+ true
+ }
+ _ => {
+ self.tcx
+ .sess
+ .emit_err(errors::AllowInternalUnstable { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ /// Checks if the items on the `#[debugger_visualizer]` attribute are valid.
+ fn check_debugger_visualizer(&self, attr: &Attribute, target: Target) -> bool {
+ match target {
+ Target::Mod => {}
+ _ => {
+ self.tcx.sess.emit_err(errors::DebugVisualizerPlacement { span: attr.span });
+ return false;
+ }
+ }
+
+ let Some(hints) = attr.meta_item_list() else {
+ self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
+ return false;
+ };
+
+ let hint = match hints.len() {
+ 1 => &hints[0],
+ _ => {
+ self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
+ return false;
+ }
+ };
+
+ let Some(meta_item) = hint.meta_item() else {
+ self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: attr.span });
+ return false;
+ };
+
+ let visualizer_path = match (meta_item.name_or_empty(), meta_item.value_str()) {
+ (sym::natvis_file, Some(value)) => value,
+ (sym::gdb_script_file, Some(value)) => value,
+ (_, _) => {
+ self.tcx.sess.emit_err(errors::DebugVisualizerInvalid { span: meta_item.span });
+ return false;
+ }
+ };
+
+ let file =
+ match resolve_path(&self.tcx.sess.parse_sess, visualizer_path.as_str(), attr.span) {
+ Ok(file) => file,
+ Err(mut err) => {
+ err.emit();
+ return false;
+ }
+ };
+
+ match std::fs::File::open(&file) {
+ Ok(_) => true,
+ Err(err) => {
+ self.tcx
+ .sess
+ .struct_span_err(
+ meta_item.span,
+ &format!("couldn't read {}: {}", file.display(), err),
+ )
+ .emit();
+ false
+ }
+ }
+ }
+
+ /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
+ /// (Allows proc_macro functions)
+ fn check_rustc_allow_const_fn_unstable(
+ &self,
+ hir_id: HirId,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ Target::Fn | Target::Method(_)
+ if self.tcx.is_const_fn_raw(self.tcx.hir().local_def_id(hir_id).to_def_id()) =>
+ {
+ true
+ }
+ // FIXME(#80564): We permit struct fields and match arms to have an
+ // `#[allow_internal_unstable]` attribute with just a lint, because we previously
+ // erroneously allowed it and some crates used it accidentally, to to be compatible
+ // with crates depending on them, we can't throw an error here.
+ Target::Field | Target::Arm | Target::MacroDef => {
+ self.inline_attr_str_error_with_macro_def(hir_id, attr, "allow_internal_unstable");
+ true
+ }
+ _ => {
+ self.tcx
+ .sess
+ .emit_err(errors::RustcAllowConstFnUnstable { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ fn check_rustc_std_internal_symbol(
+ &self,
+ attr: &Attribute,
+ span: Span,
+ target: Target,
+ ) -> bool {
+ match target {
+ Target::Fn | Target::Static => true,
+ _ => {
+ self.tcx
+ .sess
+ .emit_err(errors::RustcStdInternalSymbol { attr_span: attr.span, span });
+ false
+ }
+ }
+ }
+
+ /// `#[const_trait]` only applies to traits.
+ fn check_const_trait(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
+ match target {
+ Target::Trait => true,
+ _ => {
+ self.tcx.sess.emit_err(errors::ConstTrait { attr_span: attr.span });
+ false
+ }
+ }
+ }
+
+ fn check_stability_promotable(&self, attr: &Attribute, _span: Span, target: Target) -> bool {
+ match target {
+ Target::Expression => {
+ self.tcx.sess.emit_err(errors::StabilityPromotable { attr_span: attr.span });
+ false
+ }
+ _ => true,
+ }
+ }
+
+ fn check_deprecated(&self, hir_id: HirId, attr: &Attribute, _span: Span, target: Target) {
+ match target {
+ Target::Closure | Target::Expression | Target::Statement | Target::Arm => {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::Deprecated,
+ );
+ }
+ _ => {}
+ }
+ }
+
+ fn check_macro_use(&self, hir_id: HirId, attr: &Attribute, target: Target) {
+ let name = attr.name_or_empty();
+ match target {
+ Target::ExternCrate | Target::Mod => {}
+ _ => {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::MacroUse { name },
+ );
+ }
+ }
+ }
+
+ fn check_macro_export(&self, hir_id: HirId, attr: &Attribute, target: Target) {
+ if target != Target::MacroDef {
+ self.tcx.emit_spanned_lint(UNUSED_ATTRIBUTES, hir_id, attr.span, errors::MacroExport);
+ }
+ }
+
+ fn check_plugin_registrar(&self, hir_id: HirId, attr: &Attribute, target: Target) {
+ if target != Target::Fn {
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::PluginRegistrar,
+ );
+ }
+ }
+
+ fn check_unused_attribute(&self, hir_id: HirId, attr: &Attribute) {
+ // Warn on useless empty attributes.
+ let note = if matches!(
+ attr.name_or_empty(),
+ sym::macro_use
+ | sym::allow
+ | sym::expect
+ | sym::warn
+ | sym::deny
+ | sym::forbid
+ | sym::feature
+ | sym::repr
+ | sym::target_feature
+ ) && attr.meta_item_list().map_or(false, |list| list.is_empty())
+ {
+ errors::UnusedNote::EmptyList { name: attr.name_or_empty() }
+ } else if matches!(
+ attr.name_or_empty(),
+ sym::allow | sym::warn | sym::deny | sym::forbid | sym::expect
+ ) && let Some(meta) = attr.meta_item_list()
+ && meta.len() == 1
+ && let Some(item) = meta[0].meta_item()
+ && let MetaItemKind::NameValue(_) = &item.kind
+ && item.path == sym::reason
+ {
+ errors::UnusedNote::NoLints { name: attr.name_or_empty() }
+ } else if attr.name_or_empty() == sym::default_method_body_is_const {
+ errors::UnusedNote::DefaultMethodBodyConst
+ } else {
+ return;
+ };
+
+ self.tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ attr.span,
+ errors::Unused { attr_span: attr.span, note },
+ );
+ }
+}
+
+impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {
+ type NestedFilter = nested_filter::OnlyBodies;
+
+ fn nested_visit_map(&mut self) -> Self::Map {
+ self.tcx.hir()
+ }
+
+ fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
+ // Historically we've run more checks on non-exported than exported macros,
+ // so this lets us continue to run them while maintaining backwards compatibility.
+ // In the long run, the checks should be harmonized.
+ if let ItemKind::Macro(ref macro_def, _) = item.kind {
+ let def_id = item.def_id.to_def_id();
+ if macro_def.macro_rules && !self.tcx.has_attr(def_id, sym::macro_export) {
+ check_non_exported_macro_for_invalid_attrs(self.tcx, item);
+ }
+ }
+
+ let target = Target::from_item(item);
+ self.check_attributes(item.hir_id(), item.span, target, Some(ItemLike::Item(item)));
+ intravisit::walk_item(self, item)
+ }
+
+ fn visit_generic_param(&mut self, generic_param: &'tcx hir::GenericParam<'tcx>) {
+ let target = Target::from_generic_param(generic_param);
+ self.check_attributes(generic_param.hir_id, generic_param.span, target, None);
+ intravisit::walk_generic_param(self, generic_param)
+ }
+
+ fn visit_trait_item(&mut self, trait_item: &'tcx TraitItem<'tcx>) {
+ let target = Target::from_trait_item(trait_item);
+ self.check_attributes(trait_item.hir_id(), trait_item.span, target, None);
+ intravisit::walk_trait_item(self, trait_item)
+ }
+
+ fn visit_field_def(&mut self, struct_field: &'tcx hir::FieldDef<'tcx>) {
+ self.check_attributes(struct_field.hir_id, struct_field.span, Target::Field, None);
+ intravisit::walk_field_def(self, struct_field);
+ }
+
+ fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
+ self.check_attributes(arm.hir_id, arm.span, Target::Arm, None);
+ intravisit::walk_arm(self, arm);
+ }
+
+ fn visit_foreign_item(&mut self, f_item: &'tcx ForeignItem<'tcx>) {
+ let target = Target::from_foreign_item(f_item);
+ self.check_attributes(f_item.hir_id(), f_item.span, target, Some(ItemLike::ForeignItem));
+ intravisit::walk_foreign_item(self, f_item)
+ }
+
+ fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
+ let target = target_from_impl_item(self.tcx, impl_item);
+ self.check_attributes(impl_item.hir_id(), impl_item.span, target, None);
+ intravisit::walk_impl_item(self, impl_item)
+ }
+
+ fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt<'tcx>) {
+ // When checking statements ignore expressions, they will be checked later.
+ if let hir::StmtKind::Local(ref l) = stmt.kind {
+ self.check_attributes(l.hir_id, stmt.span, Target::Statement, None);
+ }
+ intravisit::walk_stmt(self, stmt)
+ }
+
+ fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
+ let target = match expr.kind {
+ hir::ExprKind::Closure { .. } => Target::Closure,
+ _ => Target::Expression,
+ };
+
+ self.check_attributes(expr.hir_id, expr.span, target, None);
+ intravisit::walk_expr(self, expr)
+ }
+
+ fn visit_variant(
+ &mut self,
+ variant: &'tcx hir::Variant<'tcx>,
+ generics: &'tcx hir::Generics<'tcx>,
+ item_id: HirId,
+ ) {
+ self.check_attributes(variant.id, variant.span, Target::Variant, None);
+ intravisit::walk_variant(self, variant, generics, item_id)
+ }
+
+ fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {
+ self.check_attributes(param.hir_id, param.span, Target::Param, None);
+
+ intravisit::walk_param(self, param);
+ }
+}
+
+fn is_c_like_enum(item: &Item<'_>) -> bool {
+ if let ItemKind::Enum(ref def, _) = item.kind {
+ for variant in def.variants {
+ match variant.data {
+ hir::VariantData::Unit(..) => { /* continue */ }
+ _ => return false,
+ }
+ }
+ true
+ } else {
+ false
+ }
+}
+
+// FIXME: Fix "Cannot determine resolution" error and remove built-in macros
+// from this check.
+fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
+ // Check for builtin attributes at the crate level
+ // which were unsuccessfully resolved due to cannot determine
+ // resolution for the attribute macro error.
+ const ATTRS_TO_CHECK: &[Symbol] = &[
+ sym::macro_export,
+ sym::repr,
+ sym::path,
+ sym::automatically_derived,
+ sym::start,
+ sym::rustc_main,
+ sym::derive,
+ sym::test,
+ sym::test_case,
+ sym::global_allocator,
+ sym::bench,
+ ];
+
+ for attr in attrs {
+ // This function should only be called with crate attributes
+ // which are inner attributes always but lets check to make sure
+ if attr.style == AttrStyle::Inner {
+ for attr_to_check in ATTRS_TO_CHECK {
+ if attr.has_name(*attr_to_check) {
+ let mut err = tcx.sess.struct_span_err(
+ attr.span,
+ &format!(
+ "`{}` attribute cannot be used at crate level",
+ attr_to_check.to_ident_string()
+ ),
+ );
+ // Only emit an error with a suggestion if we can create a
+ // string out of the attribute span
+ if let Ok(src) = tcx.sess.source_map().span_to_snippet(attr.span) {
+ let replacement = src.replace("#!", "#");
+ err.span_suggestion_verbose(
+ attr.span,
+ "perhaps you meant to use an outer attribute",
+ replacement,
+ rustc_errors::Applicability::MachineApplicable,
+ );
+ }
+ err.emit();
+ }
+ }
+ }
+ }
+}
+
+fn check_non_exported_macro_for_invalid_attrs(tcx: TyCtxt<'_>, item: &Item<'_>) {
+ let attrs = tcx.hir().attrs(item.hir_id());
+
+ for attr in attrs {
+ if attr.has_name(sym::inline) {
+ tcx.sess.emit_err(errors::NonExportedMacroInvalidAttrs { attr_span: attr.span });
+ }
+ }
+}
+
+fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
+ let check_attr_visitor = &mut CheckAttrVisitor { tcx };
+ tcx.hir().visit_item_likes_in_module(module_def_id, check_attr_visitor);
+ if module_def_id.is_top_level_module() {
+ check_attr_visitor.check_attributes(CRATE_HIR_ID, DUMMY_SP, Target::Mod, None);
+ check_invalid_crate_level_attr(tcx, tcx.hir().krate_attrs());
+ }
+}
+
+pub(crate) fn provide(providers: &mut Providers) {
+ *providers = Providers { check_mod_attrs, ..*providers };
+}
+
+fn check_duplicates(
+ tcx: TyCtxt<'_>,
+ attr: &Attribute,
+ hir_id: HirId,
+ duplicates: AttributeDuplicates,
+ seen: &mut FxHashMap<Symbol, Span>,
+) {
+ use AttributeDuplicates::*;
+ if matches!(duplicates, WarnFollowingWordOnly) && !attr.is_word() {
+ return;
+ }
+ match duplicates {
+ DuplicatesOk => {}
+ WarnFollowing | FutureWarnFollowing | WarnFollowingWordOnly | FutureWarnPreceding => {
+ match seen.entry(attr.name_or_empty()) {
+ Entry::Occupied(mut entry) => {
+ let (this, other) = if matches!(duplicates, FutureWarnPreceding) {
+ let to_remove = entry.insert(attr.span);
+ (to_remove, attr.span)
+ } else {
+ (attr.span, *entry.get())
+ };
+ tcx.emit_spanned_lint(
+ UNUSED_ATTRIBUTES,
+ hir_id,
+ this,
+ errors::UnusedDuplicate {
+ this,
+ other,
+ warning: matches!(
+ duplicates,
+ FutureWarnFollowing | FutureWarnPreceding
+ )
+ .then_some(()),
+ },
+ );
+ }
+ Entry::Vacant(entry) => {
+ entry.insert(attr.span);
+ }
+ }
+ }
+ ErrorFollowing | ErrorPreceding => match seen.entry(attr.name_or_empty()) {
+ Entry::Occupied(mut entry) => {
+ let (this, other) = if matches!(duplicates, ErrorPreceding) {
+ let to_remove = entry.insert(attr.span);
+ (to_remove, attr.span)
+ } else {
+ (attr.span, *entry.get())
+ };
+ tcx.sess.emit_err(errors::UnusedMultiple {
+ this,
+ other,
+ name: attr.name_or_empty(),
+ });
+ }
+ Entry::Vacant(entry) => {
+ entry.insert(attr.span);
+ }
+ },
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-09 13:27:39 +0000