std: rewrite Hash to make it more generic

This patch merges IterBytes and Hash traits, which clears up the
confusion of using `#[deriving(IterBytes)]` to support hashing.
Instead, it now is much easier to use the new `#[deriving(Hash)]`
for making a type hashable with a stream hash.

Furthermore, it supports custom non-stream-based hashers, such as
if a value's hash was cached in a database.

This does not yet replace the old IterBytes-hash with this new
version.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/libextra/stats.rs b/src/libextra/stats.rs
index 181ea6766c5..6738275c4c1 100644
--- a/src/libextra/stats.rs
+++ b/src/libextra/stats.rs
@@ -11,6 +11,7 @@
 #[allow(missing_doc)];
 
 use std::cmp;
+use std::hash_old::Hash;
 use std::hashmap;
 use std::io;
 use std::mem;