diff --git a/src/libcollections/binary_heap.rs b/src/libcollections/binary_heap.rs
index 942115926989..be99c4c0bc72 100644
--- a/src/libcollections/binary_heap.rs
+++ b/src/libcollections/binary_heap.rs
@@ -29,14 +29,12 @@
 //! use std::collections::BinaryHeap;
 //! use std::uint;
 //!
-//! #[deriving(Eq, PartialEq)]
+//! #[deriving(Copy, Eq, PartialEq)]
 //! struct State {
 //!     cost: uint,
 //!     position: uint
 //! }
 //!
-//! impl Copy for State {}
-//!
 //! // The priority queue depends on `Ord`.
 //! // Explicitly implement the trait so the queue becomes a min-heap
 //! // instead of a max-heap.
diff --git a/src/libcollections/enum_set.rs b/src/libcollections/enum_set.rs
index 49b66ce25f57..caa2051c3f9c 100644
--- a/src/libcollections/enum_set.rs
+++ b/src/libcollections/enum_set.rs
@@ -301,14 +301,12 @@ mod test {
 
     use super::{EnumSet, CLike};
 
-    #[deriving(PartialEq, Show)]
+    #[deriving(Copy, PartialEq, Show)]
     #[repr(uint)]
     enum Foo {
         A, B, C
     }
 
-    impl Copy for Foo {}
-
     impl CLike for Foo {
         fn to_uint(&self) -> uint {
             *self as uint
@@ -507,6 +505,7 @@ mod test {
     #[should_fail]
     fn test_overflow() {
         #[allow(dead_code)]
+        #[deriving(Copy)]
         #[repr(uint)]
         enum Bar {
             V00, V01, V02, V03, V04, V05, V06, V07, V08, V09,
@@ -518,8 +517,6 @@ mod test {
             V60, V61, V62, V63, V64, V65, V66, V67, V68, V69,
         }
 
-        impl Copy for Bar {}
-
         impl CLike for Bar {
             fn to_uint(&self) -> uint {
                 *self as uint
diff --git a/src/libcollections/slice.rs b/src/libcollections/slice.rs
index d3790e320ad6..3bf10192e596 100644
--- a/src/libcollections/slice.rs
+++ b/src/libcollections/slice.rs
@@ -91,7 +91,7 @@ use alloc::boxed::Box;
 use core::borrow::{BorrowFrom, BorrowFromMut, ToOwned};
 use core::cmp;
 use core::iter::{range_step, MultiplicativeIterator};
-use core::kinds::{Copy, Sized};
+use core::kinds::Sized;
 use core::mem::size_of;
 use core::mem;
 use core::ops::FnMut;
@@ -177,18 +177,16 @@ impl ElementSwaps {
     }
 }
 
+#[deriving(Copy)]
 enum Direction { Pos, Neg }
 
-impl Copy for Direction {}
-
 /// An `Index` and `Direction` together.
+#[deriving(Copy)]
 struct SizeDirection {
     size: uint,
     dir: Direction,
 }
 
-impl Copy for SizeDirection {}
-
 impl Iterator<(uint, uint)> for ElementSwaps {
     #[inline]
     fn next(&mut self) -> Option<(uint, uint)> {
diff --git a/src/libcore/hash/sip.rs b/src/libcore/hash/sip.rs
index 15f6768edce5..e10f5a9fed18 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.