Regression test for #13655

Closes #13655.

src/test/run-pass/issue-13655.rs

@@ -0,0 +1,27 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(unboxed_closures)]
+use std::ops::Fn;
+
+struct Foo<T>(T);
+
+impl<T: Copy> Fn<(), T> for Foo<T> {
+    extern "rust-call" fn call(&self, _: ()) -> T {
+      match *self {
+        Foo(t) => t
+      }
+    }
+}
+
+fn main() {
+  let t: u8 = 1;
+  println!("{}", Foo(t)());
+}