scope (global) [
    [pixel__ps_main]  : () -> float4
    [foo]             : () -> float4
    [vertex__vs_main] : (pos : float3) -> float3
    scope (vertex__vs_main) [
        [pos]             : float3
    ]
    scope (foo) []
    scope (pixel__ps_main) [
        [y]               : float4
        [color]           : float4
    ]
]