Given something like a=x3(ramp((uint32)b, (uint32)e, 2)), which is type uint32x6, we should be able to do cast(UInt(1, 6), a), but currently fail with an assertion error, because the cast() operation assumes that a Broadcast node won't contain Ramp nodes. Normally you wouldn't be likely to see this, but it's legal IR and the fuzzers will generate it.