Simplify iterator logic for Fuse

Author: frewsxcv

src/libcore/iter.rs

@@ -2174,13 +2174,10 @@ impl<I> Iterator for Fuse<I> where I: Iterator {
         if self.done {
             None
         } else {
-            match self.iter.next() {
-                None => {
-                    self.done = true;
-                    None
-                }
-                x => x
-            }
+            self.iter.next().or_else(|| {
+                self.done = true;
+                None
+            })
         }
     }
 
@@ -2201,13 +2198,10 @@ impl<I> DoubleEndedIterator for Fuse<I> where I: DoubleEndedIterator {
         if self.done {
             None
         } else {
-            match self.iter.next_back() {
-                None => {
-                    self.done = true;
-                    None
-                }
-                x => x
-            }
+            self.iter.next_back().or_else(|| {
+                self.done = true;
+                None
+            })
         }
     }
 }