Implement FusedIterator for those which already have the property by design.

Author: adamreichold

src/iter.rs

@@ -143,6 +143,7 @@ macro_rules! axis_iterators {
                     $i(self.0)
                 }
             }
+            impl<'a, T: 'a> FusedIterator for $i<'a, T> {}
             impl<'a, T: 'a> Iterator for $i<'a, T> {
                 type Item = NodeRef<'a, T>;
                 fn next(&mut self) -> Option<Self::Item> {
@@ -186,6 +187,7 @@ impl<'a, T: 'a> Clone for Children<'a, T> {
         }
     }
 }
+impl<'a, T: 'a> FusedIterator for Children<'a, T> {}
 impl<'a, T: 'a> Iterator for Children<'a, T> {
     type Item = NodeRef<'a, T>;
     fn next(&mut self) -> Option<Self::Item> {

tests/iter.rs

@@ -61,6 +61,23 @@ fn ancestors() {
     );
 }
 
+#[test]
+fn ancestors_fused() {
+    let tree = tree!('a' => { 'b' => { 'c' => { 'd' } } });
+    let d = tree
+        .root()
+        .last_child()
+        .unwrap()
+        .last_child()
+        .unwrap()
+        .last_child()
+        .unwrap();
+
+    let mut ancestors = d.ancestors();
+    assert_eq!(ancestors.by_ref().count(), 3);
+    assert_eq!(ancestors.next(), None);
+}
+
 #[test]
 fn prev_siblings() {
     let tree = tree!('a' => { 'b', 'c', 'd' });
@@ -101,6 +118,16 @@ fn children() {
     );
 }
 
+#[test]
+fn children_fused() {
+    let tree = tree!('a' => { 'b', 'c', 'd' });
+
+    let mut children = tree.root().children();
+
+    assert_eq!(children.by_ref().count(), 3);
+    assert_eq!(children.next(), None);
+}
+
 #[test]
 fn children_rev() {
     let tree = tree!('a' => { 'b', 'c', 'd' });