rollup merge of #21842: alexcrichton/issue-21839

Now that associated types are fully implemented the iterator adaptors only need
type parameters which are associated with actual storage. All other type
parameters can either be derived from these (e.g. they are an associated type)
or can be bare on the `impl` block itself.

This is a breaking change due to the removal of type parameters on these
iterator adaptors, but code can fairly easily migrate by just deleting the
relevant type parameters for each adaptor. Other behavior should not be
affected.

Closes #21839
[breaking-change]

2 files changed, 6 insertions, 16 deletions

diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index ee091d1786b..7b3cc434f0c 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -1300,18 +1300,13 @@ pub struct IterMut<'a, K: 'a, V: 'a> {
 /// HashMap move iterator.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct IntoIter<K, V> {
-    inner: iter::Map<
-        (SafeHash, K, V),
-        (K, V),
-        table::IntoIter<K, V>,
-        fn((SafeHash, K, V)) -> (K, V),
-    >
+    inner: iter::Map<table::IntoIter<K, V>, fn((SafeHash, K, V)) -> (K, V)>
 }
 
 /// HashMap keys iterator.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Keys<'a, K: 'a, V: 'a> {
-    inner: Map<(&'a K, &'a V), &'a K, Iter<'a, K, V>, fn((&'a K, &'a V)) -> &'a K>
+    inner: Map<Iter<'a, K, V>, fn((&'a K, &'a V)) -> &'a K>
 }
 
 // FIXME(#19839) Remove in favor of `#[derive(Clone)]`
@@ -1326,7 +1321,7 @@ impl<'a, K, V> Clone for Keys<'a, K, V> {
 /// HashMap values iterator.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Values<'a, K: 'a, V: 'a> {
-    inner: Map<(&'a K, &'a V), &'a V, Iter<'a, K, V>, fn((&'a K, &'a V)) -> &'a V>
+    inner: Map<Iter<'a, K, V>, fn((&'a K, &'a V)) -> &'a V>
 }
 
 // FIXME(#19839) Remove in favor of `#[derive(Clone)]`
@@ -1342,12 +1337,7 @@ impl<'a, K, V> Clone for Values<'a, K, V> {
 #[unstable(feature = "std_misc",
            reason = "matches collection reform specification, waiting for dust to settle")]
 pub struct Drain<'a, K: 'a, V: 'a> {
-    inner: iter::Map<
-        (SafeHash, K, V),
-        (K, V),
-        table::Drain<'a, K, V>,
-        fn((SafeHash, K, V)) -> (K, V),
-    >
+    inner: iter::Map<table::Drain<'a, K, V>, fn((SafeHash, K, V)) -> (K, V)>
 }
 
 /// A view into a single occupied location in a HashMap.
diff --git a/src/libstd/collections/hash/set.rs b/src/libstd/collections/hash/set.rs
index ae9fb9bca77..f5877e1dd99 100644
--- a/src/libstd/collections/hash/set.rs
+++ b/src/libstd/collections/hash/set.rs
@@ -796,13 +796,13 @@ pub struct Iter<'a, K: 'a> {
 /// HashSet move iterator
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct IntoIter<K> {
-    iter: Map<(K, ()), K, map::IntoIter<K, ()>, fn((K, ())) -> K>
+    iter: Map<map::IntoIter<K, ()>, fn((K, ())) -> K>
 }
 
 /// HashSet drain iterator
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Drain<'a, K: 'a> {
-    iter: Map<(K, ()), K, map::Drain<'a, K, ()>, fn((K, ())) -> K>,
+    iter: Map<map::Drain<'a, K, ()>, fn((K, ())) -> K>,
 }
 
 /// Intersection iterator