[Implementation] Unrestricted variables in choice rules.

[iensen]

The following program:

sorts

s = {0,1}.

predicates
p(#s).
rules
1{p(X)}1 :- X<1.

Incorrectly classifies variable X as unrestricted.
The translation should be
1{p(X):s(X)}1 :- X<1,s(X).