--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.api.test/src/com/oracle/truffle/api/InterfaceChildFieldTest.java	Wed Dec 02 15:16:27 2015 +0100
@@ -0,0 +1,172 @@
+/*
+ * Copyright (c) 2014, 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.api;
+
+import com.oracle.truffle.api.CallTarget;
+import com.oracle.truffle.api.Truffle;
+import com.oracle.truffle.api.TruffleRuntime;
+import com.oracle.truffle.api.frame.VirtualFrame;
+import com.oracle.truffle.api.nodes.Node;
+import com.oracle.truffle.api.nodes.NodeInterface;
+import com.oracle.truffle.api.nodes.NodeUtil;
+import com.oracle.truffle.api.nodes.RootNode;
+import com.oracle.truffle.api.utilities.InstrumentationTestMode;
+
+import java.util.Iterator;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Test child fields declared with interface types instead of {@link Node} subclasses.
+ */
+public class InterfaceChildFieldTest {
+
+    @Before
+    public void before() {
+        InstrumentationTestMode.set(true);
+    }
+
+    @After
+    public void after() {
+        InstrumentationTestMode.set(false);
+    }
+
+    @Test
+    public void testChild() {
+        TruffleRuntime runtime = Truffle.getRuntime();
+        TestChildInterface leftChild = new TestLeafNode();
+        TestChildInterface rightChild = new TestLeafNode();
+        TestChildNode parent = new TestChildNode(leftChild, rightChild);
+        TestRootNode rootNode = new TestRootNode(parent);
+        CallTarget target = runtime.createCallTarget(rootNode);
+        Iterator<Node> iterator = parent.getChildren().iterator();
+        Assert.assertEquals(leftChild, iterator.next());
+        Assert.assertEquals(rightChild, iterator.next());
+        Assert.assertFalse(iterator.hasNext());
+        Object result = target.call();
+        Assert.assertEquals(42, result);
+
+        Assert.assertEquals(4, NodeUtil.countNodes(rootNode));
+        Assert.assertEquals(4, NodeUtil.countNodes(NodeUtil.cloneNode(rootNode)));
+    }
+
+    @Test
+    public void testChildren() {
+        TruffleRuntime runtime = Truffle.getRuntime();
+        TestChildInterface[] children = new TestChildInterface[5];
+        for (int i = 0; i < children.length; i++) {
+            children[i] = new TestLeafNode();
+        }
+        TestChildrenNode parent = new TestChildrenNode(children);
+        TestRootNode rootNode = new TestRootNode(parent);
+        CallTarget target = runtime.createCallTarget(rootNode);
+        Iterator<Node> iterator = parent.getChildren().iterator();
+        for (int i = 0; i < children.length; i++) {
+            Assert.assertEquals(children[i], iterator.next());
+        }
+        Assert.assertFalse(iterator.hasNext());
+        Object result = target.call();
+        Assert.assertEquals(105, result);
+
+        Assert.assertEquals(2 + children.length, NodeUtil.countNodes(rootNode));
+        Assert.assertEquals(2 + children.length, NodeUtil.countNodes(NodeUtil.cloneNode(rootNode)));
+    }
+
+    class TestRootNode extends RootNode {
+
+        @Child private TestChildInterface child;
+
+        public TestRootNode(TestChildInterface child) {
+            super(TestingLanguage.class, null, null);
+            this.child = child;
+        }
+
+        @Override
+        public Object execute(VirtualFrame frame) {
+            return child.executeIntf();
+        }
+    }
+
+    interface TestChildInterface extends NodeInterface {
+        int executeIntf();
+    }
+
+    class TestLeafNode extends Node implements TestChildInterface {
+        public TestLeafNode() {
+            super(null);
+        }
+
+        public int executeIntf() {
+            return this.replace(new TestLeaf2Node()).executeIntf();
+        }
+    }
+
+    class TestLeaf2Node extends Node implements TestChildInterface {
+        public TestLeaf2Node() {
+            super(null);
+        }
+
+        public int executeIntf() {
+            return 21;
+        }
+    }
+
+    class TestChildNode extends Node implements TestChildInterface {
+
+        @Child private TestChildInterface left;
+        @Child private TestChildInterface right;
+
+        public TestChildNode(TestChildInterface left, TestChildInterface right) {
+            super(null);
+            this.left = left;
+            this.right = right;
+        }
+
+        @Override
+        public int executeIntf() {
+            return left.executeIntf() + right.executeIntf();
+        }
+    }
+
+    class TestChildrenNode extends Node implements TestChildInterface {
+
+        @Children private final TestChildInterface[] children;
+
+        public TestChildrenNode(TestChildInterface[] children) {
+            super(null);
+            this.children = children;
+        }
+
+        @Override
+        public int executeIntf() {
+            int sum = 0;
+            for (int i = 0; i < children.length; ++i) {
+                sum += children[i].executeIntf();
+            }
+            return sum;
+        }
+    }
+}