Strange error message on impl name resolution error

``` .rs
struct Foo;

mod bar {
    impl Foo {
        fn f() { }
    }
}
```

gives

```
baz.rs:4:10: 4:13 error: found module name used as a type: impl bar::Foo::Foo (id=7)
baz.rs:4     impl Foo {
```

when the actual issue is that one should write `impl super::Foo` or similar.

rustc 0.11.0 (49bc17bfdd7143909aede81652d7d624cecd8a70 2014-07-07 17:16:34 +0000)
