DSTify Hash

- The signature of the `*_equiv` methods of `HashMap` and similar structures
have changed, and now require one less level of indirection. Change your code
from:

```
hashmap.find_equiv(&"Hello");
hashmap.find_equiv(&&[0u8, 1, 2]);
```

to:

```
hashmap.find_equiv("Hello");
hashmap.find_equiv(&[0u8, 1, 2]);
```

- The generic parameter `T` of the `Hasher::hash<T>` method have become
`Sized?`. Downstream code must add `Sized?` to that method in their
implementations. For example:

```
impl Hasher<FnvState> for FnvHasher {
    fn hash<T: Hash<FnvState>>(&self, t: &T) -> u64 { /* .. */ }
}
```

must be changed to:

```
impl Hasher<FnvState> for FnvHasher {
    fn hash<Sized? T: Hash<FnvState>>(&self, t: &T) -> u64 { /* .. */ }
    //      ^^^^^^
}
```

[breaking-change]

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libsyntax/diagnostics/registry.rs b/src/libsyntax/diagnostics/registry.rs
index 7bc191df55a..71d82a41f38 100644
--- a/src/libsyntax/diagnostics/registry.rs
+++ b/src/libsyntax/diagnostics/registry.rs
@@ -20,6 +20,6 @@ impl Registry {
     }
 
     pub fn find_description(&self, code: &str) -> Option<&'static str> {
-        self.descriptions.find_equiv(&code).map(|desc| *desc)
+        self.descriptions.find_equiv(code).map(|desc| *desc)
     }
 }