std: Stabilize the `hash` module

This commit is an implementation of [RFC 823][rfc] which is another pass over
the `std::hash` module for stabilization. The contents of the module were not
entirely marked stable, but some portions which remained quite similar to the
previous incarnation are now marked `#[stable]`. Specifically:

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0823-hash-simplification.md

* `std::hash` is now stable (the name)
* `Hash` is now stable
* `Hash::hash` is now stable
* `Hasher` is now stable
* `SipHasher` is now stable
* `SipHasher::new` and `new_with_keys` are now stable
* `Hasher for SipHasher` is now stable
* Many `Hash` implementations are now stable

All other portions of the `hash` module remain `#[unstable]` as they are less
commonly used and were recently redesigned.

This commit is a breaking change due to the modifications to the `std::hash` API
and more details can be found on the [RFC][rfc].

Closes #22467
[breaking-change]

1 files changed, 48 insertions, 73 deletions

diff --git a/src/libstd/collections/hash/set.rs b/src/libstd/collections/hash/set.rs
index 5fbbcb3b347..7ff76452c1a 100644
--- a/src/libstd/collections/hash/set.rs
+++ b/src/libstd/collections/hash/set.rs
@@ -17,14 +17,14 @@ use core::marker::Sized;
 use default::Default;
 use fmt::Debug;
 use fmt;
-use hash::{self, Hash};
+use hash::Hash;
 use iter::{
     Iterator, IntoIterator, ExactSizeIterator, IteratorExt, FromIterator, Map, Chain, Extend,
 };
 use ops::{BitOr, BitAnd, BitXor, Sub};
 use option::Option::{Some, None, self};
 
-use super::map::{self, HashMap, Keys, INITIAL_CAPACITY, RandomState, Hasher};
+use super::map::{self, HashMap, Keys, INITIAL_CAPACITY, RandomState};
 use super::state::HashState;
 
 // Future Optimization (FIXME!)
@@ -97,7 +97,7 @@ pub struct HashSet<T, S = RandomState> {
     map: HashMap<T, (), S>
 }
 
-impl<T: Hash<Hasher> + Eq> HashSet<T, RandomState> {
+impl<T: Hash + Eq> HashSet<T, RandomState> {
     /// Create an empty HashSet.
     ///
     /// # Example
@@ -128,10 +128,8 @@ impl<T: Hash<Hasher> + Eq> HashSet<T, RandomState> {
     }
 }
 
-impl<T, S, H> HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<T, S> HashSet<T, S>
+    where T: Eq + Hash, S: HashState
 {
     /// Creates a new empty hash set which will use the given hasher to hash
     /// keys.
@@ -462,7 +460,7 @@ impl<T, S, H> HashSet<T, S>
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool
-        where Q: BorrowFrom<T> + Hash<H> + Eq
+        where Q: BorrowFrom<T> + Hash + Eq
     {
         self.map.contains_key(value)
     }
@@ -572,17 +570,15 @@ impl<T, S, H> HashSet<T, S>
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool
-        where Q: BorrowFrom<T> + Hash<H> + Eq
+        where Q: BorrowFrom<T> + Hash + Eq
     {
         self.map.remove(value).is_some()
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> PartialEq for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<T, S> PartialEq for HashSet<T, S>
+    where T: Eq + Hash, S: HashState
 {
     fn eq(&self, other: &HashSet<T, S>) -> bool {
         if self.len() != other.len() { return false; }
@@ -592,17 +588,14 @@ impl<T, S, H> PartialEq for HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> Eq for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<T, S> Eq for HashSet<T, S>
+    where T: Eq + Hash, S: HashState
 {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> fmt::Debug for HashSet<T, S>
-    where T: Eq + Hash<H> + fmt::Debug,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<T, S> fmt::Debug for HashSet<T, S>
+    where T: Eq + Hash + fmt::Debug,
+          S: HashState
 {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(f, "HashSet {{"));
@@ -617,10 +610,9 @@ impl<T, S, H> fmt::Debug for HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> FromIterator<T> for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
+impl<T, S> FromIterator<T> for HashSet<T, S>
+    where T: Eq + Hash,
+          S: HashState + Default,
 {
     fn from_iter<I: Iterator<Item=T>>(iter: I) -> HashSet<T, S> {
         let lower = iter.size_hint().0;
@@ -631,10 +623,9 @@ impl<T, S, H> FromIterator<T> for HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> Extend<T> for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<T, S> Extend<T> for HashSet<T, S>
+    where T: Eq + Hash,
+          S: HashState,
 {
     fn extend<I: Iterator<Item=T>>(&mut self, iter: I) {
         for k in iter {
@@ -644,10 +635,9 @@ impl<T, S, H> Extend<T> for HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> Default for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
+impl<T, S> Default for HashSet<T, S>
+    where T: Eq + Hash,
+          S: HashState + Default,
 {
     #[stable(feature = "rust1", since = "1.0.0")]
     fn default() -> HashSet<T, S> {
@@ -656,10 +646,9 @@ impl<T, S, H> Default for HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T, S, H> BitOr<&'b HashSet<T, S>> for &'a HashSet<T, S>
-    where T: Eq + Hash<H> + Clone,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
+impl<'a, 'b, T, S> BitOr<&'b HashSet<T, S>> for &'a HashSet<T, S>
+    where T: Eq + Hash + Clone,
+          S: HashState + Default,
 {
     type Output = HashSet<T, S>;
 
@@ -689,10 +678,9 @@ impl<'a, 'b, T, S, H> BitOr<&'b HashSet<T, S>> for &'a HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T, S, H> BitAnd<&'b HashSet<T, S>> for &'a HashSet<T, S>
-    where T: Eq + Hash<H> + Clone,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
+impl<'a, 'b, T, S> BitAnd<&'b HashSet<T, S>> for &'a HashSet<T, S>
+    where T: Eq + Hash + Clone,
+          S: HashState + Default,
 {
     type Output = HashSet<T, S>;
 
@@ -722,10 +710,9 @@ impl<'a, 'b, T, S, H> BitAnd<&'b HashSet<T, S>> for &'a HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T, S, H> BitXor<&'b HashSet<T, S>> for &'a HashSet<T, S>
-    where T: Eq + Hash<H> + Clone,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
+impl<'a, 'b, T, S> BitXor<&'b HashSet<T, S>> for &'a HashSet<T, S>
+    where T: Eq + Hash + Clone,
+          S: HashState + Default,
 {
     type Output = HashSet<T, S>;
 
@@ -755,10 +742,9 @@ impl<'a, 'b, T, S, H> BitXor<&'b HashSet<T, S>> for &'a HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T, S, H> Sub<&'b HashSet<T, S>> for &'a HashSet<T, S>
-    where T: Eq + Hash<H> + Clone,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
+impl<'a, 'b, T, S> Sub<&'b HashSet<T, S>> for &'a HashSet<T, S>
+    where T: Eq + Hash + Clone,
+          S: HashState + Default,
 {
     type Output = HashSet<T, S>;
 
@@ -836,10 +822,8 @@ pub struct Union<'a, T: 'a, S: 'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> IntoIterator for &'a HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<'a, T, S> IntoIterator for &'a HashSet<T, S>
+    where T: Eq + Hash, S: HashState
 {
     type Item = &'a T;
     type IntoIter = Iter<'a, T>;
@@ -850,10 +834,9 @@ impl<'a, T, S, H> IntoIterator for &'a HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> IntoIterator for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<T, S> IntoIterator for HashSet<T, S>
+    where T: Eq + Hash,
+          S: HashState
 {
     type Item = T;
     type IntoIter = IntoIter<T>;
@@ -900,10 +883,8 @@ impl<'a, K> ExactSizeIterator for Drain<'a, K> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> Iterator for Intersection<'a, T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<'a, T, S> Iterator for Intersection<'a, T, S>
+    where T: Eq + Hash, S: HashState
 {
     type Item = &'a T;
 
@@ -925,10 +906,8 @@ impl<'a, T, S, H> Iterator for Intersection<'a, T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> Iterator for Difference<'a, T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<'a, T, S> Iterator for Difference<'a, T, S>
+    where T: Eq + Hash, S: HashState
 {
     type Item = &'a T;
 
@@ -950,10 +929,8 @@ impl<'a, T, S, H> Iterator for Difference<'a, T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> Iterator for SymmetricDifference<'a, T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S>
+    where T: Eq + Hash, S: HashState
 {
     type Item = &'a T;
 
@@ -962,10 +939,8 @@ impl<'a, T, S, H> Iterator for SymmetricDifference<'a, T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> Iterator for Union<'a, T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
+impl<'a, T, S> Iterator for Union<'a, T, S>
+    where T: Eq + Hash, S: HashState
 {
     type Item = &'a T;