docs: public final CallSite acceptGetProperty(Object receiver) {
  //        if (GroovyCategorySupport.hasCategoryInCurrentThread() || !(receiver instanceof GroovyObject) || ((GroovyObject)receiver).getMetaClass() != metaClass) {
          if (GroovyCategorySupport.hasCategoryInCurrentThread() || receiver==null || receiver.getClass() != metaClass.getTheClass()
              || version != metaClass.getVersion()) { // metaClass is invalid
              return createGetPropertySite(receiver);
          } else {
              return this;
          }
      }