Fallout: add phantomdata to hash

Author: nikomatsakis

src/libstd/collections/hash/state.rs

@@ -11,6 +11,7 @@
 use clone::Clone;
 use default::Default;
 use hash;
+use marker;
 
 /// A trait representing stateful hashes which can be used to hash keys in a
 /// `HashMap`.
@@ -37,17 +38,17 @@ pub trait HashState {
 ///
 /// This struct has is 0-sized and does not need construction.
 #[unstable(feature = "std_misc", reason = "hasher stuff is unclear")]
-pub struct DefaultState<H>;
+pub struct DefaultState<H>(marker::PhantomData<H>);
 
 impl<H: Default + hash::Hasher> HashState for DefaultState<H> {
     type Hasher = H;
     fn hasher(&self) -> H { Default::default() }
 }
 
 impl<H> Clone for DefaultState<H> {
-    fn clone(&self) -> DefaultState<H> { DefaultState }
+    fn clone(&self) -> DefaultState<H> { DefaultState(marker::PhantomData) }
 }
 
 impl<H> Default for DefaultState<H> {
-    fn default() -> DefaultState<H> { DefaultState }
+    fn default() -> DefaultState<H> { DefaultState(marker::PhantomData) }
 }