Since this code runs inside va_arg handling, we have to set obj = 0 here instead if immediately returning. This also means that there's actually an additional bug with the code here: https://github.com/rubinius/rubinius/blob/master/vm/llvm/jit_util.cpp#L488-L490

There we should only run the array wrapping if obj is not 0, since otherwise we would set a null pointer in an array which would cause crashes later on.