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src/libcore/iter/iterator.rs

@@ -1372,7 +1372,7 @@ pub trait Iterator {
     /// #![feature(iterator_try_fold)]
     /// let a = [1, 2, 3];
     ///
-    /// // the checked sum of all of the elements of a
+    /// // the checked sum of all of the elements of the array
     /// let sum = a.iter()
     ///            .try_fold(0i8, |acc, &x| acc.checked_add(x));
     ///
@@ -1431,7 +1431,7 @@ pub trait Iterator {
     /// ```
     /// let a = [1, 2, 3];
     ///
-    /// // the sum of all of the elements of a
+    /// // the sum of all of the elements of the array
     /// let sum = a.iter()
     ///            .fold(0, |acc, &x| acc + x);
     ///

src/libcore/iter/mod.rs

@@ -786,11 +786,8 @@ impl<A, B> Iterator for Chain<A, B> where
             }
             _ => { }
         }
-        match self.state {
-            ChainState::Both | ChainState::Back => {
-                accum = self.b.try_fold(accum, &mut f)?;
-            }
-            _ => { }
+        if let ChainState::Back = self.state {
+            accum = self.b.try_fold(accum, &mut f)?;
         }
         Try::from_ok(accum)
     }
@@ -917,11 +914,8 @@ impl<A, B> DoubleEndedIterator for Chain<A, B> where
             }
             _ => { }
         }
-        match self.state {
-            ChainState::Both | ChainState::Front => {
-                accum = self.a.try_rfold(accum, &mut f)?;
-            }
-            _ => { }
+        if let ChainState::Front = self.state {
+            accum = self.a.try_rfold(accum, &mut f)?;
         }
         Try::from_ok(accum)
     }