% Semantics can be used in uniforms even though they are ignored.

[pixel shader]
float a : SEMANTIC;

float4 main() : sv_target
{
    return a;
}

[test]
uniform 0 float 3.5
draw quad
probe all rgba (3.5, 3.5, 3.5, 3.5)


[pixel shader]
float2 a : sv_position;

float4 main() : sv_target
{
    return float4(a, a);
}

[test]
uniform 0 float4 4.0 5.0 6.0 7.0
draw quad
probe all rgba (4.0, 5.0, 4.0, 5.0)