Add test for crash in unsafe destructor check

src/test/compile-fail/unsafe-destructor-check-crash.rs

@@ -0,0 +1,23 @@
+// 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.
+
+
+
+// Regression test for issue #15557
+
+#![allow(dead_code)]
+struct AReg1<'a>(&'a u32);
+
+impl<'a> Drop for AReg1<'a> {
+//~^ ERROR: cannot implement a destructor on a structure with type parameters
+  fn drop(&mut self) {}
+}
+
+fn main() {}