:- module ho_constrained_poly_inst.
:- interface.

:- inst b == (pred(in) is semidet).

:- pred p1(pred(int)::in(b)) is semidet.

:- pred p2(pred(int)::in(I)) is semidet <= I =< b.

:- implementation.

p1(X) :-
    X(42).  % works

p2(X) :-
    X(42).  % does not work