std: Change RandomAccessIterator to use `&mut self`

Many iterators go through a closure when dealing with the `idx` method, which
are invalid after the previous change (closures cannot be invoked through a `&`
pointer). This commit alters the `fn idx` method on the RandomAccessIterator
to take `&mut self` rather than `&self`.

[breaking-change]

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libstd/slice.rs b/src/libstd/slice.rs
index 6c55195e627..309ea8623e5 100644
--- a/src/libstd/slice.rs
+++ b/src/libstd/slice.rs
@@ -489,7 +489,7 @@ impl<'a, T> RandomAccessIterator<&'a [T]> for Chunks<'a, T> {
     }
 
     #[inline]
-    fn idx(&self, index: uint) -> Option<&'a [T]> {
+    fn idx(&mut self, index: uint) -> Option<&'a [T]> {
         if index < self.indexable() {
             let lo = index * self.size;
             let mut hi = lo + self.size;
@@ -2095,7 +2095,7 @@ impl<'a, T> RandomAccessIterator<&'a T> for Items<'a, T> {
     }
 
     #[inline]
-    fn idx(&self, index: uint) -> Option<&'a T> {
+    fn idx(&mut self, index: uint) -> Option<&'a T> {
         unsafe {
             if index < self.indexable() {
                 transmute(self.ptr.offset(index as int))