default methods are broken cross crate when defined on structs

``` rust
let xs = [1, 2, 3, 9, 11]; xs.iter().take_(2).size_hint()
```

```
<anon>:9:36: 10:5 error: internal compiler error: method not found in AST map?!
<anon>:9          let xs = [1, 2, 3, 9, 11]; xs.iter().take_(2).size_hint()
<anon>:10     };
```
