Rollup merge of #47463 - bluss:fused-iterator, r=alexcrichton

Stabilize FusedIterator

FusedIterator is a marker trait that promises that the implementing
iterator continues to return `None` from `.next()` once it has returned
`None` once (and/or `.next_back()`, if implemented).

The effects of FusedIterator are already widely available through
`.fuse()`, but with stable `FusedIterator`, stable Rust users can
implement this trait for their iterators when appropriate.

Closes #35602

src/liballoc/binary_heap.rs

@@ -964,7 +964,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 /// An owning iterator over the elements of a `BinaryHeap`.
@@ -1019,7 +1019,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 /// A draining iterator over the elements of a `BinaryHeap`.
@@ -1065,7 +1065,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: 'a> FusedIterator for Drain<'a, T> {}
 
 #[stable(feature = "binary_heap_extras_15", since = "1.5.0")]

src/liballoc/boxed.rs

@@ -722,7 +722,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I: FusedIterator + ?Sized> FusedIterator for Box<I> {}
 
 

src/liballoc/btree/map.rs

@@ -1156,7 +1156,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Iter<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1235,7 +1235,7 @@ fn len(&self) -> usize {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for IterMut<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1365,7 +1365,7 @@ fn len(&self) -> usize {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<K, V> FusedIterator for IntoIter<K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1395,7 +1395,7 @@ fn len(&self) -> usize {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Keys<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1432,7 +1432,7 @@ fn len(&self) -> usize {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Values<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1482,7 +1482,7 @@ fn len(&self) -> usize {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for ValuesMut<'a, K, V> {}
 
 
@@ -1561,7 +1561,7 @@ unsafe fn next_back_unchecked(&mut self) -> (&'a K, &'a V) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Range<'a, K, V> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
@@ -1630,7 +1630,7 @@ fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for RangeMut<'a, K, V> {}
 
 impl<'a, K, V> RangeMut<'a, K, V> {

src/liballoc/btree/set.rs

@@ -946,7 +946,7 @@ impl<'a, T> ExactSizeIterator for Iter<'a, T> {
     fn len(&self) -> usize { self.iter.len() }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -971,7 +971,7 @@ impl<T> ExactSizeIterator for IntoIter<T> {
     fn len(&self) -> usize { self.iter.len() }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
@@ -997,7 +997,7 @@ fn next_back(&mut self) -> Option<&'a T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Range<'a, T> {}
 
 /// Compare `x` and `y`, but return `short` if x is None and `long` if y is None
@@ -1044,7 +1044,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: Ord> FusedIterator for Difference<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1078,7 +1078,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: Ord> FusedIterator for SymmetricDifference<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1116,7 +1116,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: Ord> FusedIterator for Intersection<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1150,5 +1150,5 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: Ord> FusedIterator for Union<'a, T> {}

src/liballoc/lib.rs

@@ -96,7 +96,6 @@
 #![feature(fmt_internals)]
 #![feature(from_ref)]
 #![feature(fundamental)]
-#![feature(fused)]
 #![feature(generic_param_attrs)]
 #![feature(i128_type)]
 #![feature(inclusive_range)]
@@ -126,7 +125,7 @@
 #![feature(exact_chunks)]
 #![feature(pointer_methods)]
 
-#![cfg_attr(not(test), feature(fused, fn_traits, placement_new_protocol, swap_with_slice, i128))]
+#![cfg_attr(not(test), feature(fn_traits, placement_new_protocol, swap_with_slice, i128))]
 #![cfg_attr(test, feature(test, box_heap))]
 
 // Allow testing this library

src/liballoc/linked_list.rs

@@ -897,7 +897,7 @@ fn next_back(&mut self) -> Option<&'a T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -946,7 +946,7 @@ fn next_back(&mut self) -> Option<&'a mut T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for IterMut<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for IterMut<'a, T> {}
 
 impl<'a, T> IterMut<'a, T> {
@@ -1117,7 +1117,7 @@ fn next_back(&mut self) -> Option<T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> ExactSizeIterator for IntoIter<T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/liballoc/str.rs

@@ -172,7 +172,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for EncodeUtf16<'a> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/liballoc/string.rs

@@ -2254,5 +2254,5 @@ fn next_back(&mut self) -> Option<char> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for Drain<'a> {}

src/liballoc/vec.rs

@@ -2273,7 +2273,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -2379,7 +2379,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Drain<'a, T> {}
 
 /// A place for insertion at the back of a `Vec`.

src/liballoc/vec_deque.rs

@@ -1991,7 +1991,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 
@@ -2084,7 +2084,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for IterMut<'a, T> {}
 
 /// An owning iterator over the elements of a `VecDeque`.
@@ -2140,7 +2140,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 /// A draining iterator over the elements of a `VecDeque`.
@@ -2247,7 +2247,7 @@ fn next_back(&mut self) -> Option<T> {
 #[stable(feature = "drain", since = "1.6.0")]
 impl<'a, T: 'a> ExactSizeIterator for Drain<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: 'a> FusedIterator for Drain<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/libcore/char.rs

@@ -643,7 +643,7 @@ fn len(&self) -> usize {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for EscapeUnicode {}
 
 #[stable(feature = "char_struct_display", since = "1.16.0")]
@@ -756,7 +756,7 @@ fn len(&self) -> usize {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for EscapeDefault {}
 
 #[stable(feature = "char_struct_display", since = "1.16.0")]
@@ -790,7 +790,7 @@ fn size_hint(&self) -> (usize, Option<usize>) { self.0.size_hint() }
 #[stable(feature = "char_escape_debug", since = "1.20.0")]
 impl ExactSizeIterator for EscapeDebug { }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for EscapeDebug {}
 
 #[stable(feature = "char_escape_debug", since = "1.20.0")]
@@ -904,5 +904,5 @@ fn next(&mut self) -> Option<Result<char, InvalidSequence>> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[unstable(feature = "decode_utf8", issue = "33906")]
 impl<I: FusedIterator<Item = u8>> FusedIterator for DecodeUtf8<I> {}

src/libcore/iter/mod.rs

@@ -344,7 +344,7 @@
 pub use self::traits::{FromIterator, IntoIterator, DoubleEndedIterator, Extend};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::traits::{ExactSizeIterator, Sum, Product};
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 pub use self::traits::FusedIterator;
 #[unstable(feature = "trusted_len", issue = "37572")]
 pub use self::traits::TrustedLen;
@@ -506,7 +506,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I> FusedIterator for Rev<I>
     where I: FusedIterator + DoubleEndedIterator {}
 
@@ -589,7 +589,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, I, T: 'a> FusedIterator for Cloned<I>
     where I: FusedIterator<Item=&'a T>, T: Clone
 {}
@@ -662,7 +662,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I> FusedIterator for Cycle<I> where I: Clone + Iterator {}
 
 /// An iterator for stepping iterators by a custom amount.
@@ -1002,7 +1002,7 @@ fn rfold<Acc, F>(self, init: Acc, mut f: F) -> Acc
 }
 
 // Note: *both* must be fused to handle double-ended iterators.
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<A, B> FusedIterator for Chain<A, B>
     where A: FusedIterator,
           B: FusedIterator<Item=A::Item>,
@@ -1262,7 +1262,7 @@ fn may_have_side_effect() -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<A, B> FusedIterator for Zip<A, B>
     where A: FusedIterator, B: FusedIterator, {}
 
@@ -1404,7 +1404,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<B, I: FusedIterator, F> FusedIterator for Map<I, F>
     where F: FnMut(I::Item) -> B {}
 
@@ -1553,7 +1553,7 @@ fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I: FusedIterator, P> FusedIterator for Filter<I, P>
     where P: FnMut(&I::Item) -> bool {}
 
@@ -1663,7 +1663,7 @@ fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<B, I: FusedIterator, F> FusedIterator for FilterMap<I, F>
     where F: FnMut(I::Item) -> Option<B> {}
 
@@ -1818,7 +1818,7 @@ fn may_have_side_effect() -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I> FusedIterator for Enumerate<I> where I: FusedIterator {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -1938,7 +1938,7 @@ fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<I: ExactSizeIterator> ExactSizeIterator for Peekable<I> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I: FusedIterator> FusedIterator for Peekable<I> {}
 
 impl<I: Iterator> Peekable<I> {
@@ -2072,7 +2072,7 @@ fn fold<Acc, Fold>(mut self, mut init: Acc, mut fold: Fold) -> Acc
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I, P> FusedIterator for SkipWhile<I, P>
     where I: FusedIterator, P: FnMut(&I::Item) -> bool {}
 
@@ -2151,7 +2151,7 @@ fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I, P> FusedIterator for TakeWhile<I, P>
     where I: FusedIterator, P: FnMut(&I::Item) -> bool {}
 
@@ -2290,7 +2290,7 @@ fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I> FusedIterator for Skip<I> where I: FusedIterator {}
 
 /// An iterator that only iterates over the first `n` iterations of `iter`.
@@ -2371,7 +2371,7 @@ fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<I> ExactSizeIterator for Take<I> where I: ExactSizeIterator {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I> FusedIterator for Take<I> where I: FusedIterator {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -2517,7 +2517,7 @@ fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I, U, F> FusedIterator for FlatMap<I, U, F>
     where I: FusedIterator, U: IntoIterator, F: FnMut(I::Item) -> U {}
 
@@ -2605,7 +2605,7 @@ fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I, U> FusedIterator for Flatten<I>
     where I: FusedIterator, U: Iterator,
           I::Item: IntoIterator<IntoIter = U, Item = U::Item> {}
@@ -2765,7 +2765,7 @@ pub struct Fuse<I> {
     done: bool
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I> FusedIterator for Fuse<I> where I: Iterator {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -2896,7 +2896,7 @@ fn may_have_side_effect() -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I> Iterator for Fuse<I> where I: FusedIterator {
     #[inline]
     fn next(&mut self) -> Option<<I as Iterator>::Item> {
@@ -2938,7 +2938,7 @@ fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
     }
 }
 
-#[unstable(feature = "fused", reason = "recently added", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I> DoubleEndedIterator for Fuse<I>
     where I: DoubleEndedIterator + FusedIterator
 {
@@ -3082,6 +3082,6 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I: FusedIterator, F> FusedIterator for Inspect<I, F>
     where F: FnMut(&I::Item) {}

src/libcore/iter/range.rs

@@ -295,7 +295,7 @@ fn next_back(&mut self) -> Option<A> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<A: Step> FusedIterator for ops::Range<A> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -322,7 +322,7 @@ fn nth(&mut self, n: usize) -> Option<A> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<A: Step> FusedIterator for ops::RangeFrom<A> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -463,5 +463,5 @@ fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R where
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<A: Step> FusedIterator for ops::RangeInclusive<A> {}

src/libcore/iter/sources.rs

@@ -41,7 +41,7 @@ impl<A: Clone> DoubleEndedIterator for Repeat<A> {
     fn next_back(&mut self) -> Option<A> { Some(self.element.clone()) }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<A: Clone> FusedIterator for Repeat<A> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -135,7 +135,7 @@ impl<A, F: FnMut() -> A> DoubleEndedIterator for RepeatWith<F> {
     fn next_back(&mut self) -> Option<A> { self.next() }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[unstable(feature = "iterator_repeat_with", issue = "48169")]
 impl<A, F: FnMut() -> A> FusedIterator for RepeatWith<F> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -259,7 +259,7 @@ fn len(&self) -> usize {
 #[unstable(feature = "trusted_len", issue = "37572")]
 unsafe impl<T> TrustedLen for Empty<T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for Empty<T> {}
 
 // not #[derive] because that adds a Clone bound on T,
@@ -340,7 +340,7 @@ fn len(&self) -> usize {
 #[unstable(feature = "trusted_len", issue = "37572")]
 unsafe impl<T> TrustedLen for Once<T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for Once<T> {}
 
 /// Creates an iterator that yields an element exactly once.

src/libcore/iter/traits.rs

@@ -959,10 +959,10 @@ fn product<I>(iter: I) -> Result<T, E>
 /// [`None`]: ../../std/option/enum.Option.html#variant.None
 /// [`Iterator::fuse`]: ../../std/iter/trait.Iterator.html#method.fuse
 /// [`Fuse`]: ../../std/iter/struct.Fuse.html
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 pub trait FusedIterator: Iterator {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, I: FusedIterator + ?Sized> FusedIterator for &'a mut I {}
 
 /// An iterator that reports an accurate length using size_hint.

src/libcore/option.rs

@@ -1051,7 +1051,7 @@ fn next_back(&mut self) -> Option<&'a A> { self.inner.next_back() }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, A> ExactSizeIterator for Iter<'a, A> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, A> FusedIterator for Iter<'a, A> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -1096,7 +1096,7 @@ fn next_back(&mut self) -> Option<&'a mut A> { self.inner.next_back() }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, A> ExactSizeIterator for IterMut<'a, A> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, A> FusedIterator for IterMut<'a, A> {}
 #[unstable(feature = "trusted_len", issue = "37572")]
 unsafe impl<'a, A> TrustedLen for IterMut<'a, A> {}
@@ -1133,7 +1133,7 @@ fn next_back(&mut self) -> Option<A> { self.inner.next_back() }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<A> ExactSizeIterator for IntoIter<A> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<A> FusedIterator for IntoIter<A> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]

src/libcore/result.rs

@@ -1038,7 +1038,7 @@ fn next_back(&mut self) -> Option<&'a T> { self.inner.take() }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -1082,7 +1082,7 @@ fn next_back(&mut self) -> Option<&'a mut T> { self.inner.take() }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for IterMut<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for IterMut<'a, T> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -1125,7 +1125,7 @@ fn next_back(&mut self) -> Option<T> { self.inner.take() }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> ExactSizeIterator for IntoIter<T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]

src/libcore/slice/mod.rs

@@ -1455,7 +1455,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -1583,7 +1583,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for IterMut<'a, T> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -1731,7 +1731,7 @@ fn finish(&mut self) -> Option<&'a [T]> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T, P> FusedIterator for Split<'a, T, P> where P: FnMut(&T) -> bool {}
 
 /// An iterator over the subslices of the vector which are separated
@@ -1829,7 +1829,7 @@ fn next_back(&mut self) -> Option<&'a mut [T]> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T, P> FusedIterator for SplitMut<'a, T, P> where P: FnMut(&T) -> bool {}
 
 /// An iterator over subslices separated by elements that match a predicate
@@ -1886,7 +1886,6 @@ fn finish(&mut self) -> Option<&'a [T]> {
     }
 }
 
-//#[unstable(feature = "fused", issue = "35602")]
 #[unstable(feature = "slice_rsplit", issue = "41020")]
 impl<'a, T, P> FusedIterator for RSplit<'a, T, P> where P: FnMut(&T) -> bool {}
 
@@ -1945,7 +1944,6 @@ fn next_back(&mut self) -> Option<&'a mut [T]> {
     }
 }
 
-//#[unstable(feature = "fused", issue = "35602")]
 #[unstable(feature = "slice_rsplit", issue = "41020")]
 impl<'a, T, P> FusedIterator for RSplitMut<'a, T, P> where P: FnMut(&T) -> bool {}
 
@@ -2082,7 +2080,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
             }
         }
 
-        #[unstable(feature = "fused", issue = "35602")]
+        #[stable(feature = "fused", since = "1.26.0")]
         impl<'a, $elem, P> FusedIterator for $name<'a, $elem, P>
             where P: FnMut(&T) -> bool {}
     }
@@ -2188,7 +2186,7 @@ fn next_back(&mut self) -> Option<&'a [T]> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for Windows<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Windows<'a, T> {}
 
 #[doc(hidden)]
@@ -2307,7 +2305,7 @@ fn next_back(&mut self) -> Option<&'a [T]> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for Chunks<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Chunks<'a, T> {}
 
 #[doc(hidden)]
@@ -2423,7 +2421,7 @@ fn next_back(&mut self) -> Option<&'a mut [T]> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for ChunksMut<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for ChunksMut<'a, T> {}
 
 #[doc(hidden)]
@@ -2533,7 +2531,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[unstable(feature = "exact_chunks", issue = "47115")]
 impl<'a, T> FusedIterator for ExactChunks<'a, T> {}
 
 #[doc(hidden)]
@@ -2630,7 +2628,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[unstable(feature = "exact_chunks", issue = "47115")]
 impl<'a, T> FusedIterator for ExactChunksMut<'a, T> {}
 
 #[doc(hidden)]

src/libcore/str/mod.rs

@@ -609,7 +609,7 @@ fn next_back(&mut self) -> Option<char> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for Chars<'a> {}
 
 impl<'a> Chars<'a> {
@@ -702,7 +702,7 @@ fn next_back(&mut self) -> Option<(usize, char)> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for CharIndices<'a> {}
 
 impl<'a> CharIndices<'a> {
@@ -817,7 +817,7 @@ fn is_empty(&self) -> bool {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for Bytes<'a> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
@@ -977,10 +977,10 @@ fn clone(&self) -> Self {
             }
         }
 
-        #[unstable(feature = "fused", issue = "35602")]
+        #[stable(feature = "fused", since = "1.26.0")]
         impl<'a, P: Pattern<'a>> FusedIterator for $forward_iterator<'a, P> {}
 
-        #[unstable(feature = "fused", issue = "35602")]
+        #[stable(feature = "fused", since = "1.26.0")]
         impl<'a, P: Pattern<'a>> FusedIterator for $reverse_iterator<'a, P>
             where P::Searcher: ReverseSearcher<'a> {}
 
@@ -1337,7 +1337,7 @@ fn next_back(&mut self) -> Option<&'a str> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for Lines<'a> {}
 
 /// Created with the method [`lines_any`].
@@ -1403,7 +1403,7 @@ fn next_back(&mut self) -> Option<&'a str> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 #[allow(deprecated)]
 impl<'a> FusedIterator for LinesAny<'a> {}
 

src/libstd/ascii.rs

@@ -590,7 +590,7 @@ fn next_back(&mut self) -> Option<u8> {
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl ExactSizeIterator for EscapeDefault {}
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for EscapeDefault {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]

src/libstd/collections/hash/map.rs

@@ -1750,7 +1750,7 @@ fn len(&self) -> usize {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Iter<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1773,7 +1773,7 @@ fn len(&self) -> usize {
         self.inner.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for IterMut<'a, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
@@ -1808,7 +1808,7 @@ fn len(&self) -> usize {
         self.inner.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<K, V> FusedIterator for IntoIter<K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
@@ -1840,7 +1840,7 @@ fn len(&self) -> usize {
         self.inner.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Keys<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1863,7 +1863,7 @@ fn len(&self) -> usize {
         self.inner.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Values<'a, K, V> {}
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
@@ -1886,7 +1886,7 @@ fn len(&self) -> usize {
         self.inner.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for ValuesMut<'a, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
@@ -1921,7 +1921,7 @@ fn len(&self) -> usize {
         self.inner.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Drain<'a, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]

src/libstd/collections/hash/set.rs

@@ -1097,7 +1097,7 @@ fn len(&self) -> usize {
         self.iter.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K> FusedIterator for Iter<'a, K> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
@@ -1124,7 +1124,7 @@ fn len(&self) -> usize {
         self.iter.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<K> FusedIterator for IntoIter<K> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
@@ -1155,7 +1155,7 @@ fn len(&self) -> usize {
         self.iter.len()
     }
 }
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K> FusedIterator for Drain<'a, K> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
@@ -1208,7 +1208,7 @@ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T, S> FusedIterator for Intersection<'a, T, S>
     where T: Eq + Hash,
           S: BuildHasher
@@ -1244,7 +1244,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T, S> FusedIterator for Difference<'a, T, S>
     where T: Eq + Hash,
           S: BuildHasher
@@ -1283,7 +1283,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T, S> FusedIterator for SymmetricDifference<'a, T, S>
     where T: Eq + Hash,
           S: BuildHasher
@@ -1307,7 +1307,7 @@ fn clone(&self) -> Union<'a, T, S> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T, S> FusedIterator for Union<'a, T, S>
     where T: Eq + Hash,
           S: BuildHasher

src/libstd/lib.rs

@@ -266,7 +266,6 @@
 #![feature(float_from_str_radix)]
 #![feature(fn_traits)]
 #![feature(fnbox)]
-#![feature(fused)]
 #![feature(generic_param_attrs)]
 #![feature(hashmap_hasher)]
 #![feature(heap_api)]

src/libstd/path.rs

@@ -905,7 +905,7 @@ fn next_back(&mut self) -> Option<&'a OsStr> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for Iter<'a> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1008,7 +1008,7 @@ fn next_back(&mut self) -> Option<Component<'a>> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for Components<'a> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1076,7 +1076,7 @@ fn next(&mut self) -> Option<Self::Item> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[unstable(feature = "path_ancestors", issue = "48581")]
 impl<'a> FusedIterator for Ancestors<'a> {}
 
 ////////////////////////////////////////////////////////////////////////////////

src/libstd_unicode/char.rs

@@ -70,7 +70,7 @@ fn next(&mut self) -> Option<char> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for ToLowercase {}
 
 /// Returns an iterator that yields the uppercase equivalent of a `char`.
@@ -92,7 +92,7 @@ fn next(&mut self) -> Option<char> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for ToUppercase {}
 
 #[derive(Debug, Clone)]

src/libstd_unicode/lib.rs

@@ -36,7 +36,6 @@
 #![feature(str_internals)]
 #![feature(decode_utf8)]
 #![feature(fn_traits)]
-#![feature(fused)]
 #![feature(lang_items)]
 #![feature(non_exhaustive)]
 #![feature(staged_api)]

src/libstd_unicode/u_str.rs

@@ -127,7 +127,6 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
 impl<I> FusedIterator for Utf16Encoder<I>
     where I: FusedIterator<Item = char> {}
 
@@ -186,5 +185,5 @@ fn next_back(&mut self) -> Option<&'a str> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for SplitWhitespace<'a> {}

src/test/run-pass/issue-36053.rs

@@ -14,7 +14,6 @@
 // `FusedIterator` in std but I was not able to isolate that into an
 // external crate.
 
-#![feature(fused)]
 use std::iter::FusedIterator;
 
 struct Thing<'a>(&'a str);