From d801a4da7cc8672c3b7655ccad218ab892b8dd9b Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Thu, 12 Feb 2015 10:47:38 -0500
Subject: [PATCH] Fallout: iter, add markers or other changes such that all
 type parameters are used.

---
 src/libcore/iter.rs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/libcore/iter.rs b/src/libcore/iter.rs
index fffba1561a38..7a54aeb6b9c5 100644
--- a/src/libcore/iter.rs
+++ b/src/libcore/iter.rs
@@ -62,6 +62,7 @@ use clone::Clone;
 use cmp;
 use cmp::Ord;
 use default::Default;
+use marker;
 use mem;
 use num::{ToPrimitive, Int};
 use ops::{Add, Deref, FnMut};
@@ -947,7 +948,7 @@ pub trait IteratorExt: Iterator + Sized {
         FromB: Default + Extend<B>,
         Self: Iterator<Item=(A, B)>,
     {
-        struct SizeHint<A>(usize, Option<usize>);
+        struct SizeHint<A>(usize, Option<usize>, marker::PhantomData<A>);
         impl<A> Iterator for SizeHint<A> {
             type Item = A;
 
@@ -961,8 +962,8 @@ pub trait IteratorExt: Iterator + Sized {
         let mut ts: FromA = Default::default();
         let mut us: FromB = Default::default();
 
-        ts.extend(SizeHint(lo, hi));
-        us.extend(SizeHint(lo, hi));
+        ts.extend(SizeHint(lo, hi, marker::PhantomData));
+        us.extend(SizeHint(lo, hi, marker::PhantomData));
 
         for (t, u) in self {
             ts.extend(Some(t).into_iter());
@@ -2047,8 +2048,8 @@ pub struct Scan<I, St, F> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<B, I: Iterator, St, F> Iterator for Scan<I, St, F> where
-    F: FnMut(&mut St, I::Item) -> Option<B>,
+impl<A, B, I: Iterator<Item=A>, St, F> Iterator for Scan<I, St, F> where
+    F: FnMut(&mut St, A) -> Option<B>,
 {
     type Item = B;