get_leaf_domain_indices() computes wrong answer in presence of branches

This code should raise an exception, but it doesn't:

import loopy as lp

loopy_knl = lp.make_kernel(
    [
        "{[a]: 0<=a<10}",
        "{[b]: 0<=b<a}",
        "{[c]: 0<=c<a}",
    ],
    """
    """,
    "...")

print(loopy_knl)
print(loopy_knl.all_parents_per_domain())
print(loopy_knl.get_leaf_domain_indices(frozenset("bc")))

I ran into this while debugging #23 (closed) and I think it may be related....