bounded_requiring_on_class.chr

:- module(bounded_requiring_on_class, [result/1]).
:- use_module(library(prelude)).

:- chr_constraint result(int).

:- class (gt(int, int) -> bool), (gt(float, float) -> bool).
gt(X, Y) -> X > Y.

% Forbidden: requiring on :- class. Bounded polymorphism is reserved
% for :- function / :- open_function. The parser rejects this as
% RequiringOnClass (YCHR-15005).
:- class
    (pick(int, int) -> int requiring gt(int, int) -> bool),
    (pick(float, float) -> float).

pick(X, _) -> X.

result(R) <=> R is pick(1, 2).