def test_negative_2(self):
        """
        Input graph:
        input1(1, 5, 3, 4) -----> stack(axis=1) -----> reshape(shape=(-1, 5, 12, 2)) ---> out(1, 5, 6, 4)
                                    ^
                                    |
        input2(1, 5, 3, 4) ----------

        Output graph:
        Unchanged -- this graph is not equivalent to a concat.
        """

        @mb.program(
            input_specs=[mb.TensorSpec(shape=(1, 5, 3, 4)), mb.TensorSpec(shape=(1, 5, 3, 4))]
        )
        def prog(x1, x2):
            a = mb.stack(values=[x1, x2], axis=1)
            a = mb.reshape(x=a, shape=[-1, 5, 12, 2])
            return a

        prev_prog, prev_block, block = apply_pass_and_basic_check(
            prog, "common::replace_stack_reshape"
        )

        self.assertEqual(get_op_types_in_program(prev_prog), ["stack", "reshape"])
        self.assertEqual(get_op_types_in_program(prog), ["stack", "reshape"])

        Input graph:
        input1(1, 5, 3, 4) -----> stack(axis=1) -----> reshape(shape=(-1, 5, 12, 2)) ---> out(1, 5, 6, 4)
                                    ^
                                    |
        input2(1, 5, 3, 4) ----------

        Output graph:
        Unchanged -- this graph is not equivalent to a concat.
        
coremltools/converters/mil/mil/passes/tests/test_passes.py