List Parameter in Enum constructor with misbehavior

This one

 
enum MyEnum {
   ONE ([1,2]),
   TWO  ([3,4]);
   private final List myList
   MyEnum (List myList) {
        this.myList=myList
    }
}
MyEnum.ONE

leads to "groovy.lang.GroovyRuntimeException: Could not find matching constructor for: MyEnum(java.lang.String, java.lang.Integer, java.lang.Integer, java.lang.Integer)"

Adding "as List" to the List declaration works:

 
enum MyEnum {
   ONE ([1,2] as List),
   TWO  ([3,4] as List);
   private final List myList
   MyEnum (List myList) {
        this.myList=myList
    }
}
MyEnum.ONE

Why isn't "[x,y,z]" interpreted as a List in construction of enum instances?
Bug or a feature?

-----------
blackdrag: "looks like a bug for me.. please fill a report in JIRA"