float4 foo();

float3 vs_main(float3 pos : POSITION) : SV_POSITION
{
    return pos;
}

float4 foo()
{
    return float4(1.0f, 1.0f, 1.0f, 1.0f);
}

float4 ps_main() : SV_TARGET
{
    float4 y = foo();
    float4 color = y;
    return color;
}