Ports #[macro_use] and #[macro_escape] to the new attribute parsing infrastructure

JonathanBrouwer · JonathanBrouwer · commit a71aef6ebe3d · 2025-07-14T17:50:57.000+02:00
Signed-off-by: Jonathan Brouwer &lt;jonathantbrouwer@gmail.com&gt;
diff --git a/compiler/rustc_attr_data_structures/src/attributes.rs b/compiler/rustc_attr_data_structures/src/attributes.rs
@@ -3,7 +3,7 @@ use rustc_ast::token::CommentKind;
 use rustc_ast::{self as ast, AttrStyle};
 use rustc_macros::{Decodable, Encodable, HashStable_Generic, PrintAttribute};
 use rustc_span::hygiene::Transparency;
-use rustc_span::{Span, Symbol};
+use rustc_span::{Ident, Span, Symbol};
 use thin_vec::ThinVec;
 
 use crate::{DefaultBodyStability, PartialConstStability, PrintAttribute, RustcVersion, Stability};
@@ -140,6 +140,13 @@ pub enum UsedBy {
     Linker,
 }
 
+#[derive(Encodable, Decodable, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(HashStable_Generic, PrintAttribute)]
+pub enum MacroUseArgs {
+    UseAll,
+    UseSpecific(ThinVec<Ident>),
+}
+
 /// Represents parsed *built-in* inert attributes.
 ///
 /// ## Overview
@@ -306,9 +313,15 @@ pub enum AttributeKind {
     /// Represents `#[loop_match]`.
     LoopMatch(Span),
 
+    /// Represents `#[macro_escape]`.
+    MacroEscape(Span),
+
     /// Represents `#[rustc_macro_transparency]`.
     MacroTransparency(Transparency),
 
+    /// Represents `#[macro_use]`.
+    MacroUse { span: Span, arguments: MacroUseArgs },
+
     /// Represents `#[marker]`.
     Marker(Span),
 
diff --git a/compiler/rustc_attr_data_structures/src/encode_cross_crate.rs b/compiler/rustc_attr_data_structures/src/encode_cross_crate.rs
@@ -44,7 +44,9 @@ impl AttributeKind {
             LinkOrdinal { .. } => No,
             LinkSection { .. } => No,
             LoopMatch(..) => No,
+            MacroEscape(..) => No,
             MacroTransparency(..) => Yes,
+            MacroUse { .. } => No,
             Marker(..) => No,
             MayDangle(..) => No,
             MustUse { .. } => Yes,
diff --git a/compiler/rustc_attr_data_structures/src/lib.rs b/compiler/rustc_attr_data_structures/src/lib.rs
@@ -24,7 +24,7 @@ use rustc_ast::token::CommentKind;
 use rustc_ast::{AttrStyle, IntTy, UintTy};
 use rustc_ast_pretty::pp::Printer;
 use rustc_span::hygiene::Transparency;
-use rustc_span::{Span, Symbol};
+use rustc_span::{Ident, Span, Symbol};
 pub use stability::*;
 use thin_vec::ThinVec;
 pub use version::*;
@@ -172,7 +172,7 @@ macro_rules! print_tup {
 print_tup!(A B C D E F G H);
 print_skip!(Span, ());
 print_disp!(u16, bool, NonZero<u32>);
-print_debug!(Symbol, UintTy, IntTy, Align, AttrStyle, CommentKind, Transparency);
+print_debug!(Symbol, Ident, UintTy, IntTy, Align, AttrStyle, CommentKind, Transparency);
 
 /// Finds attributes in sequences of attributes by pattern matching.
 ///
diff --git a/compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs b/compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs
@@ -0,0 +1,105 @@
+use rustc_attr_data_structures::{AttributeKind, MacroUseArgs};
+use rustc_errors::DiagArgValue;
+use rustc_feature::{AttributeTemplate, template};
+use rustc_span::{Ident, Span, Symbol, sym};
+use thin_vec::ThinVec;
+
+use crate::attributes::{AcceptMapping, AttributeParser, NoArgsAttributeParser, OnDuplicate};
+use crate::context::{AcceptContext, FinalizeContext, Stage};
+use crate::parser::ArgParser;
+use crate::session_diagnostics;
+
+pub(crate) struct MacroEscapeParser;
+impl<S: Stage> NoArgsAttributeParser<S> for MacroEscapeParser {
+    const PATH: &[Symbol] = &[sym::macro_escape];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::MacroEscape;
+}
+
+/// `#[macro_use]` attributes can either:
+/// - Use all macros from a crate, if provided without arguments
+/// - Use specific macros from a crate, if provided with arguments `#[macro_use(macro1, macro2)]`
+/// A warning should be provided if an use all is combined with specific uses, or if multiple use-alls are used.
+#[derive(Default)]
+pub(crate) struct MacroUseParser {
+    /// All specific imports found so far
+    uses: ThinVec<Ident>,
+    /// Span of the first `#[macro_use]` arguments without arguments, used for linting
+    use_all: Option<Span>,
+    /// Spans of all `#[macro_use]` arguments with arguments, used for linting
+    uses_attr_spans: ThinVec<Span>,
+    /// Span of the first `#[macro_use]` argument, used as the span for this attribute
+    first_span: Option<Span>,
+}
+
+const MACRO_USE_TEMPLATE: AttributeTemplate = template!(Word, List: "name1, name2, ...");
+
+impl<S: Stage> AttributeParser<S> for MacroUseParser {
+    const ATTRIBUTES: AcceptMapping<Self, S> = &[(
+        &[sym::macro_use],
+        MACRO_USE_TEMPLATE,
+        |group: &mut Self, cx: &mut AcceptContext<'_, '_, S>, args| {
+            let span = cx.attr_span;
+            group.first_span.get_or_insert(span);
+            match args {
+                ArgParser::NoArgs => {
+                    // If there is a `#[macro_use]` import already, give a warning
+                    if let Some(old_attr) = group.use_all.replace(span) {
+                        cx.warn_unused_duplicate(old_attr, span);
+                    }
+                }
+                ArgParser::List(list) => {
+                    let mut arguments = ThinVec::new();
+
+                    if list.is_empty() {
+                        cx.warn_empty_attribute(list.span);
+                        return;
+                    }
+                    group.uses_attr_spans.push(cx.attr_span);
+
+                    for item in list.mixed() {
+                        let Some(item) = item.meta_item() else {
+                            cx.expected_identifier(item.span());
+                            continue;
+                        };
+                        if let Err(err_span) = item.args().no_args() {
+                            cx.expected_no_args(err_span);
+                            continue;
+                        }
+                        let Some(item) = item.path().word() else {
+                            cx.expected_identifier(item.span());
+                            continue;
+                        };
+                        arguments.push(item);
+                    }
+
+                    group.uses.extend(arguments);
+                }
+                ArgParser::NameValue(_) => {
+                    let suggestions = MACRO_USE_TEMPLATE.suggestions(false, sym::macro_use);
+                    cx.emit_err(session_diagnostics::IllFormedAttributeInputLint {
+                        num_suggestions: suggestions.len(),
+                        suggestions: DiagArgValue::StrListSepByAnd(
+                            suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
+                        ),
+                        span,
+                    });
+                    return;
+                }
+            };
+        },
+    )];
+
+    fn finalize(self, cx: &mut FinalizeContext<'_, '_, S>) -> Option<AttributeKind> {
+        let arguments = if let Some(use_all) = self.use_all {
+            // If there is a `#[macro_use]` attribute, warn on all `#[macro_use(...)]` attributes since everything is already imported
+            for specific_use in self.uses_attr_spans {
+                cx.warn_unused_duplicate(use_all, specific_use);
+            }
+            MacroUseArgs::UseAll
+        } else {
+            MacroUseArgs::UseSpecific(self.uses)
+        };
+        Some(AttributeKind::MacroUse { span: self.first_span?, arguments })
+    }
+}
diff --git a/compiler/rustc_attr_parsing/src/attributes/mod.rs b/compiler/rustc_attr_parsing/src/attributes/mod.rs
@@ -35,6 +35,7 @@ pub(crate) mod inline;
 pub(crate) mod link_attrs;
 pub(crate) mod lint_helpers;
 pub(crate) mod loop_match;
+pub(crate) mod macro_attrs;
 pub(crate) mod must_use;
 pub(crate) mod no_implicit_prelude;
 pub(crate) mod non_exhaustive;
diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
@@ -31,6 +31,7 @@ use crate::attributes::lint_helpers::{
     AsPtrParser, AutomaticallyDerivedParser, PassByValueParser, PubTransparentParser,
 };
 use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
+use crate::attributes::macro_attrs::{MacroEscapeParser, MacroUseParser};
 use crate::attributes::must_use::MustUseParser;
 use crate::attributes::no_implicit_prelude::NoImplicitPreludeParser;
 use crate::attributes::non_exhaustive::NonExhaustiveParser;
@@ -124,6 +125,7 @@ attribute_parsers!(
         BodyStabilityParser,
         ConfusablesParser,
         ConstStabilityParser,
+        MacroUseParser,
         NakedParser,
         StabilityParser,
         UsedParser,
@@ -170,6 +172,7 @@ attribute_parsers!(
         Single<WithoutArgs<FfiPureParser>>,
         Single<WithoutArgs<FundamentalParser>>,
         Single<WithoutArgs<LoopMatchParser>>,
+        Single<WithoutArgs<MacroEscapeParser>>,
         Single<WithoutArgs<MarkerParser>>,
         Single<WithoutArgs<MayDangleParser>>,
         Single<WithoutArgs<NoImplicitPreludeParser>>,
@@ -359,6 +362,17 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         })
     }
 
+    /// emit an error that a `name` was expected here
+    pub(crate) fn expected_identifier(&self, span: Span) -> ErrorGuaranteed {
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            attribute: self.attr_path.clone(),
+            reason: AttributeParseErrorReason::ExpectedIdentifier,
+        })
+    }
+
     /// emit an error that a `name = value` pair was expected at this span. The symbol can be given for
     /// a nicer error message talking about the specific name that was found lacking a value.
     pub(crate) fn expected_name_value(&self, span: Span, name: Option<Symbol>) -> ErrorGuaranteed {
diff --git a/compiler/rustc_attr_parsing/src/session_diagnostics.rs b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
@@ -438,7 +438,7 @@ pub(crate) struct IllFormedAttributeInput {
 
 #[derive(Diagnostic)]
 #[diag(attr_parsing_ill_formed_attribute_input)]
-pub(crate) struct MustUseIllFormedAttributeInput {
+pub(crate) struct IllFormedAttributeInputLint {
     #[primary_span]
     pub span: Span,
     pub num_suggestions: usize,
@@ -534,6 +534,7 @@ pub(crate) enum AttributeParseErrorReason {
     ExpectedNameValue(Option<Symbol>),
     DuplicateKey(Symbol),
     ExpectedSpecificArgument { possibilities: Vec<&'static str>, strings: bool },
+    ExpectedIdentifier,
 }
 
 pub(crate) struct AttributeParseError {
@@ -585,11 +586,11 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
                 diag.code(E0538);
             }
             AttributeParseErrorReason::UnexpectedLiteral => {
-                diag.span_label(self.span, format!("didn't expect a literal here"));
+                diag.span_label(self.span, "didn't expect a literal here");
                 diag.code(E0565);
             }
             AttributeParseErrorReason::ExpectedNoArgs => {
-                diag.span_label(self.span, format!("didn't expect any arguments here"));
+                diag.span_label(self.span, "didn't expect any arguments here");
                 diag.code(E0565);
             }
             AttributeParseErrorReason::ExpectedNameValue(None) => {
@@ -627,6 +628,9 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
                     }
                 }
             }
+            AttributeParseErrorReason::ExpectedIdentifier => {
+                diag.span_label(self.span, "expected a valid identifier here");
+            }
         }
 
         let suggestions = self.template.suggestions(false, &name);
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
@@ -1302,6 +1302,7 @@ impl AttributeExt for Attribute {
             // FIXME: should not be needed anymore when all attrs are parsed
             Attribute::Parsed(AttributeKind::Deprecation { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::DocComment { span, .. }) => *span,
+            Attribute::Parsed(AttributeKind::MacroUse { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::MayDangle(span)) => *span,
             Attribute::Parsed(AttributeKind::Ignore { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::AutomaticallyDerived(span)) => *span,
diff --git a/compiler/rustc_parse/src/validate_attr.rs b/compiler/rustc_parse/src/validate_attr.rs
@@ -302,6 +302,8 @@ pub fn check_builtin_meta_item(
                 | sym::cold
                 | sym::target_feature
                 | sym::rustc_allow_const_fn_unstable
+                | sym::macro_use
+                | sym::macro_escape
                 | sym::naked
                 | sym::no_mangle
                 | sym::non_exhaustive
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
@@ -213,6 +213,12 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 Attribute::Parsed(AttributeKind::LinkSection { span: attr_span, .. }) => {
                     self.check_link_section(hir_id, *attr_span, span, target)
                 }
+                Attribute::Parsed(AttributeKind::MacroUse { span, .. }) => {
+                    self.check_macro_use(hir_id, sym::macro_use, *span, target)
+                }
+                Attribute::Parsed(AttributeKind::MacroEscape(span)) => {
+                    self.check_macro_use(hir_id, sym::macro_escape, *span, target)
+                }
                 Attribute::Parsed(AttributeKind::Naked(attr_span)) => {
                     self.check_naked(hir_id, *attr_span, span, target)
                 }
@@ -341,9 +347,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         [sym::ffi_pure, ..] => self.check_ffi_pure(attr.span(), attrs, target),
                         [sym::ffi_const, ..] => self.check_ffi_const(attr.span(), target),
                         [sym::link, ..] => self.check_link(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_unparsed(hir_id, attr, target, Target::Mod),
                         [sym::macro_export, ..] => self.check_macro_export(hir_id, attr, target),
                         [sym::should_panic, ..] => {
@@ -2298,17 +2301,14 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    fn check_macro_use(&self, hir_id: HirId, attr: &Attribute, target: Target) {
-        let Some(name) = attr.name() else {
-            return;
-        };
+    fn check_macro_use(&self, hir_id: HirId, name: Symbol, attr_span: Span, target: Target) {
         match target {
             Target::ExternCrate | Target::Mod => {}
             _ => {
                 self.tcx.emit_node_span_lint(
                     UNUSED_ATTRIBUTES,
                     hir_id,
-                    attr.span(),
+                    attr_span,
                     errors::MacroUse { name },
                 );
             }
@@ -2361,7 +2361,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         // Warn on useless empty attributes.
         // FIXME(jdonszelmann): this lint should be moved to attribute parsing, see `AcceptContext::warn_empty_attribute`
         let note = if attr.has_any_name(&[
-            sym::macro_use,
             sym::allow,
             sym::expect,
             sym::warn,
diff --git a/compiler/rustc_resolve/messages.ftl b/compiler/rustc_resolve/messages.ftl
@@ -41,8 +41,6 @@ resolve_attempt_to_use_non_constant_value_in_constant_without_suggestion =
 resolve_attributes_starting_with_rustc_are_reserved =
     attributes starting with `rustc` are reserved for use by the `rustc` compiler
 
-resolve_bad_macro_import = bad macro import
-
 resolve_binding_in_never_pattern =
     never patterns cannot contain variable bindings
     .suggestion = use a wildcard `_` instead
diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
diff --git a/compiler/rustc_resolve/src/errors.rs b/compiler/rustc_resolve/src/errors.rs
diff --git a/src/tools/clippy/clippy_lints/src/macro_use.rs b/src/tools/clippy/clippy_lints/src/macro_use.rs

Original file line number	Diff line number	Diff line change
`@@ -438,7 +438,7 @@ pub(crate) struct IllFormedAttributeInput {`
`438`	`438`
`439`	`439`	`#[derive(Diagnostic)]`
`440`	`440`	`#[diag(attr_parsing_ill_formed_attribute_input)]`
`441`		`-pub(crate) struct MustUseIllFormedAttributeInput {`
	`441`	`+pub(crate) struct IllFormedAttributeInputLint {`
`442`	`442`	`#[primary_span]`
`443`	`443`	`pub span: Span,`
`444`	`444`	`pub num_suggestions: usize,`
`@@ -534,6 +534,7 @@ pub(crate) enum AttributeParseErrorReason {`
`534`	`534`	`ExpectedNameValue(Option<Symbol>),`
`535`	`535`	`DuplicateKey(Symbol),`
`536`	`536`	`ExpectedSpecificArgument { possibilities: Vec<&'static str>, strings: bool },`
	`537`	`+ ExpectedIdentifier,`
`537`	`538`	`}`
`538`	`539`
`539`	`540`	`pub(crate) struct AttributeParseError {`
`@@ -585,11 +586,11 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {`
`585`	`586`	`diag.code(E0538);`
`586`	`587`	`}`
`587`	`588`	`AttributeParseErrorReason::UnexpectedLiteral => {`
`588`		`- diag.span_label(self.span, format!("didn't expect a literal here"));`
	`589`	`+ diag.span_label(self.span, "didn't expect a literal here");`
`589`	`590`	`diag.code(E0565);`
`590`	`591`	`}`
`591`	`592`	`AttributeParseErrorReason::ExpectedNoArgs => {`
`592`		`- diag.span_label(self.span, format!("didn't expect any arguments here"));`
	`593`	`+ diag.span_label(self.span, "didn't expect any arguments here");`
`593`	`594`	`diag.code(E0565);`
`594`	`595`	`}`
`595`	`596`	`AttributeParseErrorReason::ExpectedNameValue(None) => {`
`@@ -627,6 +628,9 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {`
`627`	`628`	`}`
`628`	`629`	`}`
`629`	`630`	`}`
	`631`	`+ AttributeParseErrorReason::ExpectedIdentifier => {`
	`632`	`+ diag.span_label(self.span, "expected a valid identifier here");`
	`633`	`+ }`
`630`	`634`	`}`
`631`	`635`
`632`	`636`	`let suggestions = self.template.suggestions(false, &name);`