libcollections: use `#[deriving(Copy)]`

1 files changed, 1 insertions, 2 deletions

diff --git a/src/libcore/hash/sip.rs b/src/libcore/hash/sip.rs
index 15f6768edce..e10f5a9fed1 100644
--- a/src/libcore/hash/sip.rs
+++ b/src/libcore/hash/sip.rs
@@ -30,6 +30,7 @@ use default::Default;
 use super::{Hash, Hasher, Writer};
 
 /// `SipState` computes a SipHash 2-4 hash over a stream of bytes.
+#[deriving(Copy)]
 pub struct SipState {
     k0: u64,
     k1: u64,
@@ -42,8 +43,6 @@ pub struct SipState {
     ntail: uint,  // how many bytes in tail are valid
 }
 
-impl Copy for SipState {}
-
 // sadly, these macro definitions can't appear later,
 // because they're needed in the following defs;
 // this design could be improved.