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.

2 files changed, 2 insertions, 0 deletions

diff --git a/src/librustc/metadata/decoder.rs b/src/librustc/metadata/decoder.rs
index 47fcc453489..88aff133fb0 100644
--- a/src/librustc/metadata/decoder.rs
+++ b/src/librustc/metadata/decoder.rs
@@ -27,6 +27,7 @@ use middle::typeck;
 use middle::astencode::vtable_decoder_helpers;
 
 use std::u64;
+use std::hash_old::Hash;
 use std::io;
 use std::io::extensions::u64_from_be_bytes;
 use std::option;
diff --git a/src/librustc/metadata/encoder.rs b/src/librustc/metadata/encoder.rs
index d2b843cdcf7..7b7f45b2d2d 100644
--- a/src/librustc/metadata/encoder.rs
+++ b/src/librustc/metadata/encoder.rs
@@ -26,6 +26,7 @@ use middle;
 use serialize::Encodable;
 use std::cast;
 use std::cell::{Cell, RefCell};
+use std::hash_old::Hash;
 use std::hashmap::{HashMap, HashSet};
 use std::io::MemWriter;
 use std::str;