assert(!job_type_is_mergeable(a, c) || job_type_is_mergeable(d, c));
assert(!job_type_is_mergeable(b, c) || job_type_is_mergeable(d, c));
assert(!job_type_is_mergeable(a, c) || job_type_is_mergeable(d, c));
assert(!job_type_is_mergeable(b, c) || job_type_is_mergeable(d, c));