--- old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/type/VoidStamp.java	2019-03-09 03:56:02.596639533 +0100
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/type/VoidStamp.java	2019-03-09 03:56:02.228636930 +0100
@@ -43,6 +43,10 @@
     }
 
     @Override
+    public void accept(Visitor v) {
+    }
+
+    @Override
     public Stamp unrestricted() {
         return this;
     }