1 files changed, 13 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-38763.rs b/tests/ui/issues/issue-38763.rs
new file mode 100644
index 000000000..a966cf217
--- /dev/null
+++ b/tests/ui/issues/issue-38763.rs
@@ -0,0 +1,13 @@
+// run-pass
+// ignore-emscripten
+
+#[repr(C)]
+pub struct Foo(i128);
+
+#[no_mangle]
+#[allow(improper_ctypes_definitions)]
+pub extern "C" fn foo(x: Foo) -> Foo { x }
+
+fn main() {
+    foo(Foo(1));
+}