Add ICE regression test for issue #16218.

This code used to produce an ICE on the definition of trait Bar
with the following message:

Type parameter out of range when substituting in region 'a (root
type=fn(Self) -> 'astr) (space=FnSpace, index=0)

Closes #16218.

src/test/compile-fail/generic-lifetime-trait-impl.rs

@@ -0,0 +1,30 @@
+// Copyright 2012 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.
+
+// This code used to produce an ICE on the definition of trait Bar
+// with the following message:
+//
+// Type parameter out of range when substituting in region 'a (root
+// type=fn(Self) -> 'astr) (space=FnSpace, index=0)
+//
+// Regression test for issue #16218.
+
+trait Bar<'a> {}
+
+trait Foo<'a> {
+    fn bar<'a, T: Bar<'a>>(self) -> &'a str;
+}
+
+impl<'a> Foo<'a> for &'a str {
+    fn bar<T: Bar<'a>>(self) -> &'a str { fail!() } //~ ERROR lifetime
+}
+
+fn main() {
+}