default TypeDeclaration asType(){
  throw new UnsupportedOperationException(String.format("%s is not a TypeDeclaration",this));
}

default TypeDeclaration asType ( ) { throw new UnsupportedOperationException ( String . format ( "%s is not a TypeDeclaration" , this ) ) ; }
return this as a typedeclaration or throw an unsupportedoperationexception
