Fix a bug with cross-crate trait impls

Closes #19056

src/test/auxiliary/traitimpl.rs

@@ -0,0 +1,17 @@
+// 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.
+
+// Test inherant trait impls work cross-crait.
+
+pub trait Bar<'a> for ?Sized : 'a {}
+
+impl<'a> Bar<'a> {
+    pub fn bar(&self) {}
+}

src/test/run-pass/trait-impl.rs

@@ -10,6 +10,10 @@
 
 // Test calling methods on an impl for a bare trait.
 
+// aux-build:traitimpl.rs
+extern crate traitimpl;
+use traitimpl::Bar;
+
 static mut COUNT: uint = 1;
 
 trait T {}
@@ -25,6 +29,9 @@ impl<'a> T+'a {
 
 impl T for int {}
 
+struct Foo;
+impl<'a> Bar<'a> for Foo {}
+
 fn main() {
     let x: &T = &42i;
 
@@ -33,4 +40,8 @@ fn main() {
     T::bar();
 
     unsafe { assert!(COUNT == 12); }
+
+    // Cross-crait case
+    let x: &Bar = &Foo;
+    x.bar();
 }