From 4b35cde904c1015df42b2c63244c1db1ed51fff9 Mon Sep 17 00:00:00 2001
From: Jana Dönszelmann <jana@donsz.nl>
Date: Mon, 11 Aug 2025 11:46:30 +0200
Subject: Support lints in early attribute parsing

---
 compiler/rustc_attr_parsing/src/interface.rs       | 32 ++++++++++++++++++----
 compiler/rustc_attr_parsing/src/lints.rs           |  6 ++--
 .../rustc_attr_parsing/src/session_diagnostics.rs  |  6 ++--
 3 files changed, 32 insertions(+), 12 deletions(-)

(limited to 'compiler/rustc_attr_parsing/src')

diff --git a/compiler/rustc_attr_parsing/src/interface.rs b/compiler/rustc_attr_parsing/src/interface.rs
index b4222e41b71..60523c2877c 100644
--- a/compiler/rustc_attr_parsing/src/interface.rs
+++ b/compiler/rustc_attr_parsing/src/interface.rs
@@ -50,6 +50,27 @@ 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 parsed = Self::parse_limited_all(
             sess,
@@ -59,7 +80,7 @@ impl<'sess> AttributeParser<'sess, Early> {
             target_span,
             target_node_id,
             features,
-            ShouldEmit::Nothing,
+            should_emit,
         );
         assert!(parsed.len() <= 1);
         parsed.pop()
@@ -84,9 +105,8 @@ impl<'sess> AttributeParser<'sess, Early> {
             target,
             OmitDoc::Skip,
             std::convert::identity,
-            |_lint| {
-                // FIXME: Can't emit lints here for now
-                // This branch can be hit when an attribute produces a warning during early parsing (such as attributes on macro calls)
+            |lint| {
+                crate::lints::emit_attribute_lint(&lint, sess);
             },
         )
     }
@@ -121,8 +141,8 @@ impl<'sess> AttributeParser<'sess, Early> {
                 cx: &mut parser,
                 target_span,
                 target_id: target_node_id,
-                emit_lint: &mut |_lint| {
-                    panic!("can't emit lints here for now (nothing uses this atm)");
+                emit_lint: &mut |lint| {
+                    crate::lints::emit_attribute_lint(&lint, sess);
                 },
             },
             attr_span: attr.span,
diff --git a/compiler/rustc_attr_parsing/src/lints.rs b/compiler/rustc_attr_parsing/src/lints.rs
index 7030f28f23c..069478e7f0c 100644
--- a/compiler/rustc_attr_parsing/src/lints.rs
+++ b/compiler/rustc_attr_parsing/src/lints.rs
@@ -1,13 +1,13 @@
 use std::borrow::Cow;
 
 use rustc_errors::{DiagArgValue, LintEmitter};
+use rustc_hir::Target;
 use rustc_hir::lints::{AttributeLint, AttributeLintKind};
-use rustc_hir::{HirId, Target};
 use rustc_span::sym;
 
 use crate::session_diagnostics;
 
-pub fn emit_attribute_lint<L: LintEmitter>(lint: &AttributeLint<HirId>, lint_emitter: L) {
+pub fn emit_attribute_lint<L: LintEmitter>(lint: &AttributeLint<L::Id>, lint_emitter: L) {
     let AttributeLint { id, span, kind } = lint;
 
     match kind {
@@ -51,7 +51,7 @@ pub fn emit_attribute_lint<L: LintEmitter>(lint: &AttributeLint<HirId>, lint_emi
                 *id,
                 *span,
                 session_diagnostics::InvalidTargetLint {
-                    name,
+                    name: name.clone(),
                     target: target.plural_name(),
                     applied: DiagArgValue::StrListSepByAnd(
                         applied.into_iter().map(|i| Cow::Owned(i.to_string())).collect(),
diff --git a/compiler/rustc_attr_parsing/src/session_diagnostics.rs b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
index 2192e8f8f83..72bee0ddfbf 100644
--- a/compiler/rustc_attr_parsing/src/session_diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
@@ -484,9 +484,9 @@ pub(crate) struct EmptyAttributeList {
 #[diag(attr_parsing_invalid_target_lint)]
 #[warning]
 #[help]
-pub(crate) struct InvalidTargetLint<'a> {
-    pub name: &'a AttrPath,
-    pub target: &'a str,
+pub(crate) struct InvalidTargetLint {
+    pub name: AttrPath,
+    pub target: &'static str,
     pub applied: DiagArgValue,
     pub only: &'static str,
     #[suggestion(code = "", applicability = "machine-applicable", style = "tool-only")]
-- 
cgit 1.4.1-3-g733a5