src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/type/NarrowOopStamp.java

*** 43,52 ****
--- 43,59 ----
          super(type, exactType, nonNull, alwaysNull);
          this.encoding = encoding;
      }
  
      @Override
+     public void accept(Visitor v) {
+         super.accept(v);
+         v.visitLong(encoding.getBase());
+         v.visitInt(encoding.getShift());
+     }
+ 
+     @Override
      protected abstract AbstractObjectStamp copyWith(ResolvedJavaType type, boolean exactType, boolean nonNull, boolean alwaysNull);
  
      public Stamp uncompressed() {
          return new ObjectStamp(type(), isExactType(), nonNull(), alwaysNull());
      }