Fix halt/1 built-in predicate for ISO Prolog Core standard compliance
@@ -1218,8 +1218,11 @@ op(Priority, OpSpec, Op) :-
halt :- halt(0).
halt(N) :-
- must_be_number(N, halt/1),
- ( -2^31 =< N, N =< 2^31 - 1 ->
+ ( var(N) ->
+ throw(error(instantiation_error, halt/1)) % 8.17.4.3 a)
+ ; \+ integer(N) ->
+ throw(error(type_error(integer, N), halt/1)) % 8.17.4.3 b)
+ ; -2^31 =< N, N =< 2^31 - 1 ->
'$halt'(N)
; throw(error(domain_error(exit_code, N), halt/1))
).
