Re: ALTER TABLE ALTER CONSTRAINT misleading error message

hi.

create table t(a int, constraint cc check(a  = 1));
ALTER TABLE t ALTER CONSTRAINT cc not valid;
ERROR:  FOREIGN KEY constraints cannot be marked NOT VALID
LINE 1: ALTER TABLE t ALTER CONSTRAINT cc not valid;
                                          ^

the error message seems misleading,
should we consider it as a bug for pg18?
the entry point is in gram.y, following part: