Use assoc types in the *Iterator traits

src/libcollections/binary_heap.rs

@@ -573,7 +573,9 @@ impl<'a, T> Clone for Iter<'a, T> {
 }
 
 #[stable]
-impl<'a, T> Iterator<&'a T> for Iter<'a, T> {
+impl<'a, T> Iterator for Iter<'a, T> {
+    type Item = &'a T;
+
     #[inline]
     fn next(&mut self) -> Option<&'a T> { self.iter.next() }
 
@@ -582,21 +584,23 @@ impl<'a, T> Iterator<&'a T> for Iter<'a, T> {
 }
 
 #[stable]
-impl<'a, T> DoubleEndedIterator<&'a T> for Iter<'a, T> {
+impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
     #[inline]
     fn next_back(&mut self) -> Option<&'a T> { self.iter.next_back() }
 }
 
 #[stable]
-impl<'a, T> ExactSizeIterator<&'a T> for Iter<'a, T> {}
+impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
 
 /// An iterator that moves out of a `BinaryHeap`.
 pub struct IntoIter<T> {
     iter: vec::IntoIter<T>,
 }
 
 #[stable]
-impl<T> Iterator<T> for IntoIter<T> {
+impl<T> Iterator for IntoIter<T> {
+    type Item = T;
+
     #[inline]
     fn next(&mut self) -> Option<T> { self.iter.next() }
 
@@ -605,21 +609,23 @@ impl<T> Iterator<T> for IntoIter<T> {
 }
 
 #[stable]
-impl<T> DoubleEndedIterator<T> for IntoIter<T> {
+impl<T> DoubleEndedIterator for IntoIter<T> {
     #[inline]
     fn next_back(&mut self) -> Option<T> { self.iter.next_back() }
 }
 
 #[stable]
-impl<T> ExactSizeIterator<T> for IntoIter<T> {}
+impl<T> ExactSizeIterator for IntoIter<T> {}
 
 /// An iterator that drains a `BinaryHeap`.
 pub struct Drain<'a, T: 'a> {
     iter: vec::Drain<'a, T>,
 }
 
 #[stable]
-impl<'a, T: 'a> Iterator<T> for Drain<'a, T> {
+impl<'a, T: 'a> Iterator for Drain<'a, T> {
+    type Item = T;
+
     #[inline]
     fn next(&mut self) -> Option<T> { self.iter.next() }
 
@@ -628,24 +634,24 @@ impl<'a, T: 'a> Iterator<T> for Drain<'a, T> {
 }
 
 #[stable]
-impl<'a, T: 'a> DoubleEndedIterator<T> for Drain<'a, T> {
+impl<'a, T: 'a> DoubleEndedIterator for Drain<'a, T> {
     #[inline]
     fn next_back(&mut self) -> Option<T> { self.iter.next_back() }
 }
 
 #[stable]
-impl<'a, T: 'a> ExactSizeIterator<T> for Drain<'a, T> {}
+impl<'a, T: 'a> ExactSizeIterator for Drain<'a, T> {}
 
 #[stable]
 impl<T: Ord> FromIterator<T> for BinaryHeap<T> {
-    fn from_iter<Iter: Iterator<T>>(iter: Iter) -> BinaryHeap<T> {
+    fn from_iter<Iter: Iterator<Item=T>>(iter: Iter) -> BinaryHeap<T> {
         BinaryHeap::from_vec(iter.collect())
     }
 }
 
 #[stable]
 impl<T: Ord> Extend<T> for BinaryHeap<T> {
-    fn extend<Iter: Iterator<T>>(&mut self, mut iter: Iter) {
+    fn extend<Iter: Iterator<Item=T>>(&mut self, mut iter: Iter) {
         let (lower, _) = iter.size_hint();
 
         self.reserve(lower);

src/libcollections/bit.rs

@@ -938,7 +938,7 @@ impl Default for Bitv {
 
 #[stable]
 impl FromIterator<bool> for Bitv {
-    fn from_iter<I:Iterator<bool>>(iterator: I) -> Bitv {
+    fn from_iter<I:Iterator<Item=bool>>(iterator: I) -> Bitv {
         let mut ret = Bitv::new();
         ret.extend(iterator);
         ret
@@ -948,7 +948,7 @@ impl FromIterator<bool> for Bitv {
 #[stable]
 impl Extend<bool> for Bitv {
     #[inline]
-    fn extend<I: Iterator<bool>>(&mut self, mut iterator: I) {
+    fn extend<I: Iterator<Item=bool>>(&mut self, mut iterator: I) {
         let (min, _) = iterator.size_hint();
         self.reserve(min);
         for element in iterator {
@@ -1031,7 +1031,9 @@ pub struct Iter<'a> {
 }
 
 #[stable]
-impl<'a> Iterator<bool> for Iter<'a> {
+impl<'a> Iterator for Iter<'a> {
+    type Item = bool;
+
     #[inline]
     fn next(&mut self) -> Option<bool> {
         if self.next_idx != self.end_idx {
@@ -1050,7 +1052,7 @@ impl<'a> Iterator<bool> for Iter<'a> {
 }
 
 #[stable]
-impl<'a> DoubleEndedIterator<bool> for Iter<'a> {
+impl<'a> DoubleEndedIterator for Iter<'a> {
     #[inline]
     fn next_back(&mut self) -> Option<bool> {
         if self.next_idx != self.end_idx {
@@ -1063,10 +1065,10 @@ impl<'a> DoubleEndedIterator<bool> for Iter<'a> {
 }
 
 #[stable]
-impl<'a> ExactSizeIterator<bool> for Iter<'a> {}
+impl<'a> ExactSizeIterator for Iter<'a> {}
 
 #[stable]
-impl<'a> RandomAccessIterator<bool> for Iter<'a> {
+impl<'a> RandomAccessIterator for Iter<'a> {
     #[inline]
     fn indexable(&self) -> uint {
         self.end_idx - self.next_idx
@@ -1134,7 +1136,7 @@ impl Default for BitvSet {
 
 #[stable]
 impl FromIterator<uint> for BitvSet {
-    fn from_iter<I:Iterator<uint>>(iterator: I) -> BitvSet {
+    fn from_iter<I:Iterator<Item=uint>>(iterator: I) -> BitvSet {
         let mut ret = BitvSet::new();
         ret.extend(iterator);
         ret
@@ -1144,7 +1146,7 @@ impl FromIterator<uint> for BitvSet {
 #[stable]
 impl Extend<uint> for BitvSet {
     #[inline]
-    fn extend<I: Iterator<uint>>(&mut self, mut iterator: I) {
+    fn extend<I: Iterator<Item=uint>>(&mut self, mut iterator: I) {
         for i in iterator {
             self.insert(i);
         }
@@ -1792,7 +1794,9 @@ pub struct Difference<'a>(TwoBitPositions<'a>);
 pub struct SymmetricDifference<'a>(TwoBitPositions<'a>);
 
 #[stable]
-impl<'a> Iterator<uint> for SetIter<'a> {
+impl<'a> Iterator for SetIter<'a> {
+    type Item = uint;
+
     fn next(&mut self) -> Option<uint> {
         while self.next_idx < self.set.bitv.len() {
             let idx = self.next_idx;
@@ -1813,7 +1817,9 @@ impl<'a> Iterator<uint> for SetIter<'a> {
 }
 
 #[stable]
-impl<'a> Iterator<uint> for TwoBitPositions<'a> {
+impl<'a> Iterator for TwoBitPositions<'a> {
+    type Item = uint;
+
     fn next(&mut self) -> Option<uint> {
         while self.next_idx < self.set.bitv.len() ||
               self.next_idx < self.other.bitv.len() {
@@ -1849,25 +1855,33 @@ impl<'a> Iterator<uint> for TwoBitPositions<'a> {
 }
 
 #[stable]
-impl<'a> Iterator<uint> for Union<'a> {
+impl<'a> Iterator for Union<'a> {
+    type Item = uint;
+
     #[inline] fn next(&mut self) -> Option<uint> { self.0.next() }
     #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.0.size_hint() }
 }
 
 #[stable]
-impl<'a> Iterator<uint> for Intersection<'a> {
+impl<'a> Iterator for Intersection<'a> {
+    type Item = uint;
+
     #[inline] fn next(&mut self) -> Option<uint> { self.0.next() }
     #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.0.size_hint() }
 }
 
 #[stable]
-impl<'a> Iterator<uint> for Difference<'a> {
+impl<'a> Iterator for Difference<'a> {
+    type Item = uint;
+
     #[inline] fn next(&mut self) -> Option<uint> { self.0.next() }
     #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.0.size_hint() }
 }
 
 #[stable]
-impl<'a> Iterator<uint> for SymmetricDifference<'a> {
+impl<'a> Iterator for SymmetricDifference<'a> {
+    type Item = uint;
+
     #[inline] fn next(&mut self) -> Option<uint> { self.0.next() }
     #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.0.size_hint() }
 }

src/libcollections/btree/map.rs

@@ -823,7 +823,7 @@ mod stack {
 
 #[stable]
 impl<K: Ord, V> FromIterator<(K, V)> for BTreeMap<K, V> {
-    fn from_iter<T: Iterator<(K, V)>>(iter: T) -> BTreeMap<K, V> {
+    fn from_iter<T: Iterator<Item=(K, V)>>(iter: T) -> BTreeMap<K, V> {
         let mut map = BTreeMap::new();
         map.extend(iter);
         map
@@ -833,7 +833,7 @@ impl<K: Ord, V> FromIterator<(K, V)> for BTreeMap<K, V> {
 #[stable]
 impl<K: Ord, V> Extend<(K, V)> for BTreeMap<K, V> {
     #[inline]
-    fn extend<T: Iterator<(K, V)>>(&mut self, mut iter: T) {
+    fn extend<T: Iterator<Item=(K, V)>>(&mut self, mut iter: T) {
         for (k, v) in iter {
             self.insert(k, v);
         }
@@ -949,8 +949,11 @@ enum StackOp<T> {
     Pop,
 }
 
-impl<K, V, E, T: Traverse<E> + DoubleEndedIterator<TraversalItem<K, V, E>>>
-        Iterator<(K, V)> for AbsIter<T> {
+impl<K, V, E, T> Iterator for AbsIter<T> where
+    T: DoubleEndedIterator + Iterator<Item=TraversalItem<K, V, E>> + Traverse<E>,
+{
+    type Item = (K, V);
+
     // This function is pretty long, but only because there's a lot of cases to consider.
     // Our iterator represents two search paths, left and right, to the smallest and largest
     // elements we have yet to yield. lca represents the least common ancestor of these two paths,
@@ -1015,8 +1018,9 @@ impl<K, V, E, T: Traverse<E> + DoubleEndedIterator<TraversalItem<K, V, E>>>
     }
 }
 
-impl<K, V, E, T: Traverse<E> + DoubleEndedIterator<TraversalItem<K, V, E>>>
-        DoubleEndedIterator<(K, V)> for AbsIter<T> {
+impl<K, V, E, T> DoubleEndedIterator for AbsIter<T> where
+    T: DoubleEndedIterator + Iterator<Item=TraversalItem<K, V, E>> + Traverse<E>,
+{
     // next_back is totally symmetric to next
     fn next_back(&mut self) -> Option<(K, V)> {
         loop {
@@ -1054,64 +1058,75 @@ impl<K, V, E, T: Traverse<E> + DoubleEndedIterator<TraversalItem<K, V, E>>>
 }
 
 #[stable]
-impl<'a, K, V> Iterator<(&'a K, &'a V)> for Iter<'a, K, V> {
+impl<'a, K, V> Iterator for Iter<'a, K, V> {
+    type Item = (&'a K, &'a V);
+
     fn next(&mut self) -> Option<(&'a K, &'a V)> { self.inner.next() }
     fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
 }
 #[stable]
-impl<'a, K, V> DoubleEndedIterator<(&'a K, &'a V)> for Iter<'a, K, V> {
+impl<'a, K, V> DoubleEndedIterator for Iter<'a, K, V> {
     fn next_back(&mut self) -> Option<(&'a K, &'a V)> { self.inner.next_back() }
 }
 #[stable]
-impl<'a, K, V> ExactSizeIterator<(&'a K, &'a V)> for Iter<'a, K, V> {}
+impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {}
 
 #[stable]
-impl<'a, K, V> Iterator<(&'a K, &'a mut V)> for IterMut<'a, K, V> {
+impl<'a, K, V> Iterator for IterMut<'a, K, V> {
+    type Item = (&'a K, &'a mut V);
+
     fn next(&mut self) -> Option<(&'a K, &'a mut V)> { self.inner.next() }
     fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
 }
 #[stable]
-impl<'a, K, V> DoubleEndedIterator<(&'a K, &'a mut V)> for IterMut<'a, K, V> {
+impl<'a, K, V> DoubleEndedIterator for IterMut<'a, K, V> {
     fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> { self.inner.next_back() }
 }
 #[stable]
-impl<'a, K, V> ExactSizeIterator<(&'a K, &'a mut V)> for IterMut<'a, K, V> {}
+impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> {}
 
 #[stable]
-impl<K, V> Iterator<(K, V)> for IntoIter<K, V> {
+impl<K, V> Iterator for IntoIter<K, V> {
+    type Item = (K, V);
+
     fn next(&mut self) -> Option<(K, V)> { self.inner.next() }
     fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
 }
 #[stable]
-impl<K, V> DoubleEndedIterator<(K, V)> for IntoIter<K, V> {
+impl<K, V> DoubleEndedIterator for IntoIter<K, V> {
     fn next_back(&mut self) -> Option<(K, V)> { self.inner.next_back() }
 }
 #[stable]
-impl<K, V> ExactSizeIterator<(K, V)> for IntoIter<K, V> {}
+impl<K, V> ExactSizeIterator for IntoIter<K, V> {}
 
 #[stable]
-impl<'a, K, V> Iterator<&'a K> for Keys<'a, K, V> {
+impl<'a, K, V> Iterator for Keys<'a, K, V> {
+    type Item = &'a K;
+
     fn next(&mut self) -> Option<(&'a K)> { self.inner.next() }
     fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
 }
 #[stable]
-impl<'a, K, V> DoubleEndedIterator<&'a K> for Keys<'a, K, V> {
+impl<'a, K, V> DoubleEndedIterator for Keys<'a, K, V> {
     fn next_back(&mut self) -> Option<(&'a K)> { self.inner.next_back() }
 }
 #[stable]
-impl<'a, K, V> ExactSizeIterator<&'a K> for Keys<'a, K, V> {}
+impl<'a, K, V> ExactSizeIterator for Keys<'a, K, V> {}
+
 
 #[stable]
-impl<'a, K, V> Iterator<&'a V> for Values<'a, K, V> {
+impl<'a, K, V> Iterator for Values<'a, K, V> {
+    type Item = &'a V;
+
     fn next(&mut self) -> Option<(&'a V)> { self.inner.next() }
     fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
 }
 #[stable]
-impl<'a, K, V> DoubleEndedIterator<&'a V> for Values<'a, K, V> {
+impl<'a, K, V> DoubleEndedIterator for Values<'a, K, V> {
     fn next_back(&mut self) -> Option<(&'a V)> { self.inner.next_back() }
 }
 #[stable]
-impl<'a, K, V> ExactSizeIterator<&'a V> for Values<'a, K, V> {}
+impl<'a, K, V> ExactSizeIterator for Values<'a, K, V> {}
 
 
 impl<'a, K: Ord, V> VacantEntry<'a, K, V> {