--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/NodeClass.java	Thu Oct 17 20:27:44 2019 +0100
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/NodeClass.java	Thu Oct 17 20:53:35 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2019, 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
@@ -126,7 +126,7 @@
             field.setAccessible(true);
             return (NodeClass<T>) field.get(null);
         } catch (IllegalArgumentException | IllegalAccessException | NoSuchFieldException | SecurityException e) {
-            throw new RuntimeException(e);
+            throw new RuntimeException("Could not load Graal NodeClass TYPE field for " + clazz, e);
         }
     }
 
@@ -741,6 +741,7 @@
             } else {
                 Object objectA = data.getObject(a, i);
                 Object objectB = data.getObject(b, i);
+                assert !isLambda(objectA) || !isLambda(objectB) : "lambdas are not permitted in fields of " + this.toString();
                 if (objectA != objectB) {
                     if (objectA != null && objectB != null) {
                         if (!deepEquals0(objectA, objectB)) {
@@ -755,6 +756,11 @@
         return true;
     }
 
+    private static boolean isLambda(Object obj) {
+        // This needs to be consistent with InnerClassLambdaMetafactory constructor.
+        return obj != null && obj.getClass().getSimpleName().contains("$$Lambda$");
+    }
+
     public boolean isValid(Position pos, NodeClass<?> from, Edges fromEdges) {
         if (this == from) {
             return true;
@@ -1217,8 +1223,8 @@
                     return false;
                 }
             } else {
-                Object v1 = Edges.getNodeListUnsafe(node, offset);
-                Object v2 = Edges.getNodeListUnsafe(other, offset);
+                NodeList<Node> v1 = Edges.getNodeListUnsafe(node, offset);
+                NodeList<Node> v2 = Edges.getNodeListUnsafe(other, offset);
                 if (!Objects.equals(v1, v2)) {
                     return false;
                 }