1 files changed, 21 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-17771.rs b/tests/ui/issues/issue-17771.rs
new file mode 100644
index 000000000..2f6464668
--- /dev/null
+++ b/tests/ui/issues/issue-17771.rs
@@ -0,0 +1,21 @@
+// run-pass
+#![allow(dead_code)]
+// pretty-expanded FIXME #23616
+
+trait Aaa { fn dummy(&self) { } }
+
+impl<'a> Aaa for &'a mut (dyn Aaa + 'a) {}
+
+struct Bar<'a> {
+    writer: &'a mut (dyn Aaa + 'a),
+}
+
+fn baz(_: &mut dyn Aaa) {
+}
+
+fn foo<'a>(mut bar: Bar<'a>) {
+    baz(&mut bar.writer);
+}
+
+fn main() {
+}