Clone the array before searching for siblings

compiler/ast/ArrayContainer.js

@@ -75,7 +75,7 @@ class ArrayContainer extends Container {
         if (node.container !== this) {
             throw new Error('Node does not belong to container: ' + node);
         }
-        var array = this.array;
+        var array = this.array.concat([]);
         var found = false;
 
         for (var i=0; i<array.length; i++) {

test/fixtures/render/autotest/for-iterator-as-target/expected.html

@@ -0,0 +1 @@
+543210

test/fixtures/render/autotest/for-iterator-as-target/template.marko

@@ -0,0 +1,3 @@
+<for(item in data.myIterator)>
+    ${item}
+</for>

test/fixtures/render/autotest/for-iterator-as-target/test.js

@@ -0,0 +1,7 @@
+exports.templateData = {
+    myIterator: function(callback) {
+        for (var i=5; i>=0; i--) {
+            callback(i);
+        }
+    }
+};