diff --git a/rocker-runtime/src/main/java/com/fizzed/rocker/runtime/IterableForIterator.java b/rocker-runtime/src/main/java/com/fizzed/rocker/runtime/IterableForIterator.java
index b1cc0ac..d4f0630 100644
--- a/rocker-runtime/src/main/java/com/fizzed/rocker/runtime/IterableForIterator.java
+++ b/rocker-runtime/src/main/java/com/fizzed/rocker/runtime/IterableForIterator.java
@@ -25,10 +25,10 @@
  */
 public class IterableForIterator<T> implements ForIterator {
 
-    private final Iterator<T> iterator;
+    private final Iterator<? extends T> iterator;
     private int index;
 
-    public IterableForIterator(Iterable<T> c) {
+    public IterableForIterator(Iterable<? extends T> c) {
         this(c.iterator());
     }
 
@@ -68,7 +68,7 @@ public IterableForIterator(double[] a) {
         this((Iterable<T>) new PrimitiveCollections.DoubleCollection(a));
     }
 
-    public IterableForIterator(Iterator<T> iterator) {
+    public IterableForIterator(Iterator<? extends T> iterator) {
         this.iterator = iterator;
         this.index = -1;
     }