Auto merge of #23300 - sfackler:rm-iterator-ext, r=alexcrichton

All methods are inlined into Iterator with `Self: Sized` bounds to make
sure Iterator is still object safe.

[breaking-change]

This is blocked on ICEs: https://gist.github.com/sfackler/5aff7c57cf8d896e2c6f
Seem to be similar to #23281.

Author: bors

src/libcollections/linked_list.rs

@@ -951,7 +951,7 @@ impl<A: Hash> Hash for LinkedList<A> {
 #[cfg(test)]
 mod test {
     use std::clone::Clone;
-    use std::iter::{Iterator, IteratorExt};
+    use std::iter::Iterator;
     use std::option::Option::{Some, None, self};
     use std::rand;
     use std::thread;

src/libcollections/slice.rs

@@ -76,7 +76,6 @@
 //!   iterators.
 //! * Further methods that return iterators are `.split()`, `.splitn()`,
 //!   `.chunks()`, `.windows()` and more.
-
 #![doc(primitive = "slice")]
 #![stable(feature = "rust1", since = "1.0.0")]
 
@@ -85,7 +84,7 @@ use core::convert::AsRef;
 use core::clone::Clone;
 use core::cmp::Ordering::{self, Greater, Less};
 use core::cmp::{self, Ord, PartialEq};
-use core::iter::{Iterator, IteratorExt};
+use core::iter::Iterator;
 use core::iter::MultiplicativeIterator;
 use core::marker::Sized;
 use core::mem::size_of;
@@ -131,7 +130,7 @@ mod hack {
     use alloc::boxed::Box;
     use core::clone::Clone;
     #[cfg(test)]
-    use core::iter::{Iterator, IteratorExt};
+    use core::iter::Iterator;
     use core::mem;
     #[cfg(test)]
     use core::option::Option::{Some, None};

src/libcollections/str.rs

@@ -58,7 +58,7 @@ use self::DecompositionType::*;
 
 use core::clone::Clone;
 use core::iter::AdditiveIterator;
-use core::iter::{Iterator, IteratorExt, Extend};
+use core::iter::{Iterator, Extend};
 use core::option::Option::{self, Some, None};
 use core::result::Result;
 use core::str as core_str;

src/libcollections/vec_deque.rs

@@ -1785,7 +1785,7 @@ impl<T: fmt::Debug> fmt::Debug for VecDeque<T> {
 
 #[cfg(test)]
 mod test {
-    use core::iter::{IteratorExt, self};
+    use core::iter::{Iterator, self};
     use core::option::Option::Some;
 
     use test;

src/libcollectionstest/bench.rs

@@ -66,7 +66,7 @@ macro_rules! map_find_rand_bench {
     ($name: ident, $n: expr, $map: ident) => (
         #[bench]
         pub fn $name(b: &mut ::test::Bencher) {
-            use std::iter::IteratorExt;
+            use std::iter::Iterator;
             use std::rand::Rng;
             use std::rand;
             use std::vec::Vec;

src/libcore/fmt/float.rs

@@ -17,7 +17,7 @@ pub use self::SignFormat::*;
 use char;
 use char::CharExt;
 use fmt;
-use iter::IteratorExt;
+use iter::Iterator;
 use num::{cast, Float, ToPrimitive};
 use num::FpCategory as Fp;
 use ops::FnOnce;

src/libcore/fmt/mod.rs

@@ -15,7 +15,7 @@
 use any;
 use cell::{Cell, RefCell, Ref, RefMut, BorrowState};
 use char::CharExt;
-use iter::{Iterator, IteratorExt};
+use iter::Iterator;
 use marker::{Copy, PhantomData, Sized};
 use mem;
 use option::Option;

src/libcore/fmt/num.rs

@@ -15,7 +15,7 @@
 #![allow(unsigned_negation)]
 
 use fmt;
-use iter::IteratorExt;
+use iter::Iterator;
 use num::{Int, cast};
 use slice::SliceExt;
 use str;