public Type inferType(List<Var> vars, List<List<Type>> varTypes) {
Type t1 = left.inferType(vars, varTypes);
Type t2 = right.inferType(vars, varTypes);
if (t1 == null || t2 == null || !t1.matches(t2)) {
inferedType = null; // update cache
return null;
}
inferedType = PType.T; // update cache
return PType.T;
}
