add test to reproduce #137687 and fix it by converting #[crate_name] to a new-style attribute parser

compiler/rustc_attr_parsing/src/attributes/crate_level.rs

@@ -0,0 +1,30 @@
+use rustc_feature::{AttributeTemplate, template};
+use rustc_hir::attrs::AttributeKind;
+use rustc_span::{Symbol, sym};
+
+use super::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::context::{AcceptContext, Stage};
+use crate::parser::ArgParser;
+
+pub(crate) struct CrateNameParser;
+
+impl<S: Stage> SingleAttributeParser<S> for CrateNameParser {
+    const PATH: &[Symbol] = &[sym::crate_name];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
+    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        let ArgParser::NameValue(n) = args else {
+            cx.expected_name_value(cx.attr_span, None);
+            return None;
+        };
+
+        let Some(name) = n.value_as_str() else {
+            cx.expected_string_literal(n.value_span, Some(n.value_as_lit()));
+            return None;
+        };
+
+        Some(AttributeKind::CrateName { name, name_span: n.value_span, style: cx.attr_style })
+    }
+}

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -31,6 +31,7 @@ pub(crate) mod cfg;
 pub(crate) mod cfg_old;
 pub(crate) mod codegen_attrs;
 pub(crate) mod confusables;
+pub(crate) mod crate_level;
 pub(crate) mod deprecation;
 pub(crate) mod dummy;
 pub(crate) mod inline;

compiler/rustc_attr_parsing/src/attributes/util.rs

@@ -1,4 +1,4 @@
-use rustc_ast::attr::{AttributeExt, first_attr_value_str_by_name};
+use rustc_ast::attr::AttributeExt;
 use rustc_feature::is_builtin_attr_name;
 use rustc_hir::RustcVersion;
 use rustc_span::{Symbol, sym};
@@ -23,10 +23,6 @@ pub fn is_builtin_attr(attr: &impl AttributeExt) -> bool {
     attr.is_doc_comment() || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name))
 }
 
-pub fn find_crate_name(attrs: &[impl AttributeExt]) -> Option<Symbol> {
-    first_attr_value_str_by_name(attrs, sym::crate_name)
-}
-
 pub fn is_doc_alias_attrs_contain_symbol<'tcx, T: AttributeExt + 'tcx>(
     attrs: impl Iterator<Item = &'tcx T>,
     symbol: Symbol,

compiler/rustc_attr_parsing/src/context.rs

@@ -4,13 +4,14 @@ use std::ops::{Deref, DerefMut};
 use std::sync::LazyLock;
 
 use private::Sealed;
-use rustc_ast::{self as ast, LitKind, MetaItemLit, NodeId};
+use rustc_ast::{self as ast, AttrStyle, LitKind, MetaItemLit, NodeId};
 use rustc_errors::{DiagCtxtHandle, Diagnostic};
 use rustc_feature::{AttributeTemplate, Features};
 use rustc_hir::attrs::AttributeKind;
 use rustc_hir::lints::{AttributeLint, AttributeLintKind};
 use rustc_hir::{AttrArgs, AttrItem, AttrPath, Attribute, HashIgnoredAttrId, HirId};
 use rustc_session::Session;
+use rustc_session::lint::BuiltinLintDiag;
 use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span, Symbol, sym};
 
 use crate::attributes::allow_unstable::{
@@ -22,6 +23,7 @@ use crate::attributes::codegen_attrs::{
     TargetFeatureParser, TrackCallerParser, UsedParser,
 };
 use crate::attributes::confusables::ConfusablesParser;
+use crate::attributes::crate_level::CrateNameParser;
 use crate::attributes::deprecation::DeprecationParser;
 use crate::attributes::dummy::DummyParser;
 use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
@@ -59,6 +61,7 @@ use crate::attributes::traits::{
 };
 use crate::attributes::transparency::TransparencyParser;
 use crate::attributes::{AttributeParser as _, Combine, Single, WithoutArgs};
+use crate::lints::lint_name;
 use crate::parser::{ArgParser, MetaItemParser, PathParser};
 use crate::session_diagnostics::{AttributeParseError, AttributeParseErrorReason, UnknownMetaItem};
 
@@ -157,6 +160,7 @@ attribute_parsers!(
 
         // tidy-alphabetical-start
         Single<CoverageParser>,
+        Single<CrateNameParser>,
         Single<DeprecationParser>,
         Single<DummyParser>,
         Single<ExportNameParser>,
@@ -301,6 +305,9 @@ pub struct AcceptContext<'f, 'sess, S: Stage> {
     /// The span of the attribute currently being parsed
     pub(crate) attr_span: Span,
 
+    /// Whether it is an inner or outer attribute
+    pub(crate) attr_style: AttrStyle,
+
     /// The expected structure of the attribute.
     ///
     /// Used in reporting errors to give a hint to users what the attribute *should* look like.
@@ -382,6 +389,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                     i.kind.is_bytestr().then(|| self.sess().source_map().start_point(i.span))
                 }),
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -392,6 +400,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedIntegerLiteral,
+            attr_style: self.attr_style,
         })
     }
 
@@ -402,6 +411,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedList,
+            attr_style: self.attr_style,
         })
     }
 
@@ -412,6 +422,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedNoArgs,
+            attr_style: self.attr_style,
         })
     }
 
@@ -423,6 +434,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedIdentifier,
+            attr_style: self.attr_style,
         })
     }
 
@@ -435,6 +447,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedNameValue(name),
+            attr_style: self.attr_style,
         })
     }
 
@@ -446,6 +459,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::DuplicateKey(key),
+            attr_style: self.attr_style,
         })
     }
 
@@ -458,6 +472,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::UnexpectedLiteral,
+            attr_style: self.attr_style,
         })
     }
 
@@ -468,6 +483,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedSingleArgument,
+            attr_style: self.attr_style,
         })
     }
 
@@ -478,6 +494,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedAtLeastOneArgument,
+            attr_style: self.attr_style,
         })
     }
 
@@ -496,6 +513,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: false,
                 list: false,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -514,6 +532,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: false,
                 list: true,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -532,6 +551,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: true,
                 list: false,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -675,22 +695,48 @@ impl<'sess> AttributeParser<'sess, Early> {
         target_span: Span,
         target_node_id: NodeId,
         features: Option<&'sess Features>,
+    ) -> Option<Attribute> {
+        Self::parse_limited_should_emit(
+            sess,
+            attrs,
+            sym,
+            target_span,
+            target_node_id,
+            features,
+            ShouldEmit::Nothing,
+        )
+    }
+
+    /// Usually you want `parse_limited`, which defaults to no errors.
+    pub fn parse_limited_should_emit(
+        sess: &'sess Session,
+        attrs: &[ast::Attribute],
+        sym: Symbol,
+        target_span: Span,
+        target_node_id: NodeId,
+        features: Option<&'sess Features>,
+        should_emit: ShouldEmit,
     ) -> Option<Attribute> {
         let mut p = Self {
             features,
             tools: Vec::new(),
             parse_only: Some(sym),
             sess,
-            stage: Early { emit_errors: ShouldEmit::Nothing },
+            stage: Early { emit_errors: should_emit },
         };
         let mut parsed = p.parse_attribute_list(
             attrs,
             target_span,
             target_node_id,
             OmitDoc::Skip,
             std::convert::identity,
-            |_lint| {
-                panic!("can't emit lints here for now (nothing uses this atm)");
+            |AttributeLint { id, span, kind }| {
+                sess.psess.buffer_lint(
+                    lint_name(&kind),
+                    span,
+                    id,
+                    BuiltinLintDiag::AttributeLint(kind),
+                );
             },
         );
         assert!(parsed.len() <= 1);
@@ -731,6 +777,7 @@ impl<'sess> AttributeParser<'sess, Early> {
                 },
             },
             attr_span: attr.span,
+            attr_style: attr.style,
             template,
             attr_path: path.get_attribute_path(),
         };
@@ -840,6 +887,7 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
                                     emit_lint: &mut emit_lint,
                                 },
                                 attr_span: lower_span(attr.span),
+                                attr_style: attr.style,
                                 template: &accept.template,
                                 attr_path: path.get_attribute_path(),
                             };

compiler/rustc_attr_parsing/src/lib.rs

@@ -92,10 +92,8 @@ mod session_diagnostics;
 
 pub use attributes::cfg::{CFG_TEMPLATE, EvalConfigResult, eval_config_entry, parse_cfg_attr};
 pub use attributes::cfg_old::*;
-pub use attributes::util::{
-    find_crate_name, is_builtin_attr, is_doc_alias_attrs_contain_symbol, parse_version,
-};
+pub use attributes::util::{is_builtin_attr, is_doc_alias_attrs_contain_symbol, parse_version};
 pub use context::{AttributeParser, Early, Late, OmitDoc, ShouldEmit};
-pub use lints::emit_attribute_lint;
+pub use lints::{emit_attribute_lint, emit_attribute_lint_kind};
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }

compiler/rustc_attr_parsing/src/lints.rs

@@ -1,38 +1,46 @@
-use rustc_errors::{DiagArgValue, LintEmitter};
+use rustc_errors::{DiagArgValue, LintEmitter, SimpleLintEmitter};
 use rustc_hir::HirId;
 use rustc_hir::lints::{AttributeLint, AttributeLintKind};
+use rustc_session::lint::Lint;
 
 use crate::session_diagnostics;
 
-pub fn emit_attribute_lint<L: LintEmitter>(lint: &AttributeLint<HirId>, lint_emitter: L) {
-    let AttributeLint { id, span, kind } = lint;
+pub(crate) fn lint_name(kind: &AttributeLintKind) -> &'static Lint {
+    use rustc_session::lint::builtin::*;
+    match kind {
+        AttributeLintKind::UnusedDuplicate { .. } => UNUSED_ATTRIBUTES,
+        AttributeLintKind::IllFormedAttributeInput { .. } => ILL_FORMED_ATTRIBUTE_INPUT,
+        AttributeLintKind::EmptyAttribute { .. } => UNUSED_ATTRIBUTES,
+    }
+}
 
+pub fn emit_attribute_lint_kind<L: SimpleLintEmitter>(kind: &AttributeLintKind, lint_emitter: L) {
     match kind {
-        &AttributeLintKind::UnusedDuplicate { this, other, warning } => lint_emitter
-            .emit_node_span_lint(
-                rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
-                *id,
-                *span,
-                session_diagnostics::UnusedDuplicate { this, other, warning },
-            ),
+        &AttributeLintKind::UnusedDuplicate { this, other, warning } => {
+            lint_emitter.emit(session_diagnostics::UnusedDuplicate { this, other, warning })
+        }
         AttributeLintKind::IllFormedAttributeInput { suggestions } => {
-            lint_emitter.emit_node_span_lint(
-                rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT,
-                *id,
-                *span,
-                session_diagnostics::IllFormedAttributeInput {
-                    num_suggestions: suggestions.len(),
-                    suggestions: DiagArgValue::StrListSepByAnd(
-                        suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
-                    ),
-                },
-            );
+            lint_emitter.emit(session_diagnostics::IllFormedAttributeInput {
+                num_suggestions: suggestions.len(),
+                suggestions: DiagArgValue::StrListSepByAnd(
+                    suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
+                ),
+            });
+        }
+        AttributeLintKind::EmptyAttribute { first_span } => {
+            lint_emitter.emit(session_diagnostics::EmptyAttributeList { attr_span: *first_span })
         }
-        AttributeLintKind::EmptyAttribute { first_span } => lint_emitter.emit_node_span_lint(
-            rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
-            *id,
-            *first_span,
-            session_diagnostics::EmptyAttributeList { attr_span: *first_span },
-        ),
     }
 }
+
+pub fn emit_attribute_lint<L: LintEmitter<ID = HirId>>(
+    lint: &AttributeLint<HirId>,
+    lint_emitter: L,
+) {
+    let AttributeLint { id, span, kind } = lint;
+
+    let lint_name = lint_name(&lint.kind);
+
+    let emit = lint_emitter.prepare_node_span_lint(lint_name, *id, *span);
+    emit_attribute_lint_kind(kind, emit);
+}

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -1,6 +1,6 @@
 use std::num::IntErrorKind;
 
-use rustc_ast as ast;
+use rustc_ast::{self as ast, AttrStyle};
 use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, EmissionGuarantee, Level,
@@ -555,6 +555,7 @@ pub(crate) enum AttributeParseErrorReason {
 pub(crate) struct AttributeParseError {
     pub(crate) span: Span,
     pub(crate) attr_span: Span,
+    pub(crate) attr_style: AttrStyle,
     pub(crate) template: AttributeTemplate,
     pub(crate) attribute: AttrPath,
     pub(crate) reason: AttributeParseErrorReason,
@@ -690,7 +691,7 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
             }
         }
 
-        let suggestions = self.template.suggestions(false, &name);
+        let suggestions = self.template.suggestions(self.attr_style == AttrStyle::Inner, &name);
         diag.span_suggestions(
             self.attr_span,
             if suggestions.len() == 1 {