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Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_passes/src/check_attr.rs | 2217 |
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 new file mode 100644 index 000000000..a2ac329f2 --- /dev/null +++ b/compiler/rustc_passes/src/check_attr.rs @@ -0,0 +1,2217 @@ +//! 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); + } + }, + } +} |