From 0cfbe56d0497f2210314c4101adff6bc74ea97f7 Mon Sep 17 00:00:00 2001
From: Linshu Yang <linshuy2@illinois.edu>
Date: Fri, 2 Jan 2026 23:07:31 +0000
Subject: [PATCH] fix: `match_as_ref` wrongly unmangled macros

---
 clippy_lints/src/matches/match_as_ref.rs |  5 +++--
 tests/ui/match_as_ref.fixed              | 10 ++++++++++
 tests/ui/match_as_ref.rs                 | 14 ++++++++++++++
 tests/ui/match_as_ref.stderr             | 23 ++++++++++++++++++++++-
 4 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/clippy_lints/src/matches/match_as_ref.rs b/clippy_lints/src/matches/match_as_ref.rs
index 795355f25f9e..12fe44ef2f13 100644
--- a/clippy_lints/src/matches/match_as_ref.rs
+++ b/clippy_lints/src/matches/match_as_ref.rs
@@ -46,6 +46,7 @@ pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr:
         let cast = if input_ty == output_ty { "" } else { ".map(|x| x as _)" };
 
         let mut applicability = Applicability::MachineApplicable;
+        let ctxt = expr.span.ctxt();
         span_lint_and_then(
             cx,
             MATCH_AS_REF,
@@ -59,7 +60,7 @@ pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr:
                         "use `Option::as_ref()`",
                         format!(
                             "{}.as_ref(){cast}",
-                            Sugg::hir_with_applicability(cx, ex, "_", &mut applicability).maybe_paren(),
+                            Sugg::hir_with_context(cx, ex, ctxt, "_", &mut applicability).maybe_paren(),
                         ),
                         applicability,
                     );
@@ -69,7 +70,7 @@ pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr:
                         format!("use `Option::{method}()` directly"),
                         format!(
                             "{}.{method}(){cast}",
-                            Sugg::hir_with_applicability(cx, ex, "_", &mut applicability).maybe_paren(),
+                            Sugg::hir_with_context(cx, ex, ctxt, "_", &mut applicability).maybe_paren(),
                         ),
                         applicability,
                     );
diff --git a/tests/ui/match_as_ref.fixed b/tests/ui/match_as_ref.fixed
index 09a6ed169390..b1b8ffb885f5 100644
--- a/tests/ui/match_as_ref.fixed
+++ b/tests/ui/match_as_ref.fixed
@@ -90,3 +90,13 @@ fn issue15932() {
 
     let _: Option<&dyn std::fmt::Debug> = Some(0).as_ref().map(|x| x as _);
 }
+
+fn wrongly_unmangled_macros() {
+    macro_rules! test_expr {
+        ($val:expr) => {
+            Some($val)
+        };
+    }
+
+    let _: Option<&u32> = test_expr!(42).as_ref();
+}
diff --git a/tests/ui/match_as_ref.rs b/tests/ui/match_as_ref.rs
index 347b6d186887..3113167957d4 100644
--- a/tests/ui/match_as_ref.rs
+++ b/tests/ui/match_as_ref.rs
@@ -114,3 +114,17 @@ fn issue15932() {
         Some(ref mut v) => Some(v),
     };
 }
+
+fn wrongly_unmangled_macros() {
+    macro_rules! test_expr {
+        ($val:expr) => {
+            Some($val)
+        };
+    }
+
+    let _: Option<&u32> = match test_expr!(42) {
+        //~^ match_as_ref
+        None => None,
+        Some(ref v) => Some(v),
+    };
+}
diff --git a/tests/ui/match_as_ref.stderr b/tests/ui/match_as_ref.stderr
index df06e358f296..3eab499fe409 100644
--- a/tests/ui/match_as_ref.stderr
+++ b/tests/ui/match_as_ref.stderr
@@ -127,5 +127,26 @@ LL -     };
 LL +     let _: Option<&dyn std::fmt::Debug> = Some(0).as_ref().map(|x| x as _);
    |
 
-error: aborting due to 6 previous errors
+error: manual implementation of `Option::as_ref`
+  --> tests/ui/match_as_ref.rs:125:27
+   |
+LL |       let _: Option<&u32> = match test_expr!(42) {
+   |  ___________________________^
+LL | |
+LL | |         None => None,
+LL | |         Some(ref v) => Some(v),
+LL | |     };
+   | |_____^
+   |
+help: use `Option::as_ref()` directly
+   |
+LL -     let _: Option<&u32> = match test_expr!(42) {
+LL -
+LL -         None => None,
+LL -         Some(ref v) => Some(v),
+LL -     };
+LL +     let _: Option<&u32> = test_expr!(42).as_ref();
+   |
+
+error: aborting due to 7 previous errors