[pixel shader]
float4 main() : sv_target
{
    float3 x = float4(71, 72, 73, 74);
    return float4(x, 75);
}

[test]
todo(msl) draw quad
probe (0, 0) rgba (71.0, 72.0, 73.0, 75.0)


[pixel shader]
struct stu
{
    float aa;
    float2 bb;
    float cc;
};

float4 main() : sv_target
{
    struct stu foo;
    foo.cc = 5;
    foo.bb = float3(2, 3, 4); // It shall not overflow to cc;
    foo.aa = 1;

    return float4(foo);
}

[test]
todo(msl) draw quad
probe (0, 0) rgba (1.0, 2.0, 3.0, 5.0)