Add test

Author: Manishearth

src/test/auxiliary/crate_a1.rs

@@ -0,0 +1,21 @@
+// Copyright 2015 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.
+
+pub struct Foo;
+
+pub trait Bar{}
+
+pub fn bar() -> Box<Bar> {
+    unimplemented!()
+}
+
+
+pub fn try_foo(x: Foo){}
+pub fn try_bar(x: Box<Bar>){}

src/test/auxiliary/crate_a2.rs

@@ -0,0 +1,17 @@
+// Copyright 2015 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.
+
+pub struct Foo;
+
+pub trait Bar{}
+
+pub fn bar() -> Box<Bar> {
+    unimplemented!()
+}

src/test/compile-fail/type-mismatch-same-crate-name.rs

@@ -0,0 +1,33 @@
+// 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.
+
+// aux-build:crate_a1.rs
+// aux-build:crate_a2.rs
+
+// This tests the extra note reported when a type error deals with
+// seemingly identical types.
+// The main use case of this error is when there are two crates
+// (generally different versions of the same crate) with the same name
+// causing a type mismatch. Here, we simulate that error using block-scoped
+// aliased `extern crate` declarations.
+
+fn main() {
+    let foo2 = {extern crate crate_a2 as a; a::Foo};
+    let bar2 = {extern crate crate_a2 as a; a::bar()};
+    {
+        extern crate crate_a1 as a;
+        a::try_foo(foo2); //~ ERROR mismatched types
+                          //~^ HELP run
+                          //~^^ NOTE Perhaps two different versions of crate `main`
+        a::try_bar(bar2); //~ ERROR mismatched types
+                          //~^ HELP run
+                          //~^^ NOTE Perhaps two different versions of crate `main`
+    }
+}