From 1f8b15fba1f405b680825ce847cf983d0a4eb3b3 Mon Sep 17 00:00:00 2001
From: Joao Roberto <dnreikronos2@gmail.com>
Date: Sat, 25 Jul 2026 12:08:44 -0300
Subject: [PATCH] Fix cfg_attr inner attributes in file modules

Return to pretty-printed token reconstruction when lexing source slices around an inner attribute produces unmatched delimiters.

Cover cfg_attr-expanded proc-macro attributes in an out-of-line module, including sibling attributes on both sides.
---
 compiler/rustc_parse/src/lib.rs                    | 14 +++++++-------
 .../inner_attr_file_mod_cfg_attr_child.rs          |  8 ++++++++
 .../ui/proc-macro/inner-attr-file-mod-cfg-attr.rs  | 14 ++++++++++++++
 3 files changed, 29 insertions(+), 7 deletions(-)
 create mode 100644 tests/ui/proc-macro/auxiliary/inner_attr_file_mod_cfg_attr_child.rs
 create mode 100644 tests/ui/proc-macro/inner-attr-file-mod-cfg-attr.rs

diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
index cd08fc3dc60a1..539c15f18a9a4 100644
--- a/compiler/rustc_parse/src/lib.rs
+++ b/compiler/rustc_parse/src/lib.rs
@@ -349,13 +349,13 @@ fn lex_token_trees_for_span(
     span: Span,
 ) -> Option<impl Iterator<Item = TokenTree>> {
     let src = psess.source_map().span_to_snippet(span).ok()?;
-    let stream = unwrap_or_emit_fatal(lexer::lex_token_trees(
-        psess,
-        &src,
-        span.lo(),
-        None,
-        StripTokens::Nothing,
-    ));
+    let stream = match lexer::lex_token_trees(psess, &src, span.lo(), None, StripTokens::Nothing) {
+        Ok(stream) => stream,
+        Err(errs) => {
+            errs.into_iter().for_each(|err| err.cancel());
+            return None;
+        }
+    };
     Some((0..).map_while(move |index| stream.get(index).cloned()))
 }
 
diff --git a/tests/ui/proc-macro/auxiliary/inner_attr_file_mod_cfg_attr_child.rs b/tests/ui/proc-macro/auxiliary/inner_attr_file_mod_cfg_attr_child.rs
new file mode 100644
index 0000000000000..59114fb8e58af
--- /dev/null
+++ b/tests/ui/proc-macro/auxiliary/inner_attr_file_mod_cfg_attr_child.rs
@@ -0,0 +1,8 @@
+#![cfg_attr(enabled, test_macros::identity_attr, allow(dead_code))]
+#![cfg_attr(enabled, allow(unused_imports), test_macros::identity_attr)]
+#![cfg_attr(enabled, test_macros::identity_attr)]
+//! docs
+
+use std::fmt;
+
+fn unused() {}
diff --git a/tests/ui/proc-macro/inner-attr-file-mod-cfg-attr.rs b/tests/ui/proc-macro/inner-attr-file-mod-cfg-attr.rs
new file mode 100644
index 0000000000000..26b6a6f7041a0
--- /dev/null
+++ b/tests/ui/proc-macro/inner-attr-file-mod-cfg-attr.rs
@@ -0,0 +1,14 @@
+//@ check-pass
+//@ proc-macro: test-macros.rs
+//@ edition:2024
+//@ compile-flags: --cfg enabled --check-cfg=cfg(enabled)
+
+#![feature(custom_inner_attributes)]
+#![deny(dead_code, unused_attributes, unused_imports)]
+
+extern crate test_macros;
+
+#[path = "auxiliary/inner_attr_file_mod_cfg_attr_child.rs"]
+mod child;
+
+fn main() {}