def test_match_bitwidth_simulates_only_wildcards(self):
        r = pyrtl.Register(6, 'r')
        r.next <<= r + 3
        # 000000 -> 000011 -> 000110 -> 001001 -> 001100 -> 001111 -> 010010 -> 010101
        a, _ = pyrtl.match_bitpattern(r, '??????')
        o = pyrtl.Output(name='o')
        o <<= a
        self.check_trace('o 11111111\nr 036912151821\n')