---

yaml
---
r: 145080
b: refs/heads/try2
c: 10c8978
h: refs/heads/master
v: v3

Author: thestinger

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 561f1b006321501dfe5a059444fc8f560010c2ba
+refs/heads/try2: 10c8978edbb53fda8b33758a0bf3f9154b20dc9e
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/libstd/iter.rs

@@ -1749,14 +1749,12 @@ impl<A: Add<A, A> + Ord + Clone> Iterator<A> for Range<A> {
     // Blocked on #8605 Need numeric trait for converting to `Option<uint>`
 }
 
-impl<A: Sub<A, A> + Integer + Ord + Clone> DoubleEndedIterator<A> for Range<A> {
+/// `Integer` is required to ensure the range will be the same regardless of
+/// the direction it is consumed.
+impl<A: Integer + Ord + Clone> DoubleEndedIterator<A> for Range<A> {
     #[inline]
     fn next_back(&mut self) -> Option<A> {
         if self.stop > self.state {
-            // Integer doesn't technically define this rule, but we're going to assume that every
-            // Integer is reachable from every other one by adding or subtracting enough Ones. This
-            // seems like a reasonable-enough rule that every Integer should conform to, even if it
-            // can't be statically checked.
             self.stop = self.stop - self.one;
             Some(self.stop.clone())
         } else {