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/libserialize/serialize.rs b/src/libserialize/serialize.rs
index e57e7adcf8d..f350bb0761f 100644
--- a/src/libserialize/serialize.rs
+++ b/src/libserialize/serialize.rs
@@ -14,6 +14,7 @@
 Core encoding and decoding interfaces.
 */
 
+use std::hash_old::Hash;
 use std::hashmap::{HashMap, HashSet};
 use std::rc::Rc;
 use std::trie::{TrieMap, TrieSet};