HLSL: reject-valid: Expected Image Operand Bias to be float scalar

[Ace17]

The following program is accepted by fxc.exe :

( http://shader-playground.timjones.io/a7903c733ae2ef2ef279ebbb62bcb539 )

Texture2D myTexture;
SamplerState mySampler;

float4 main() : SV_Target0
{
    return myTexture.SampleBias(mySampler, float2(0, 0), 0, 0);
}

However, it is rejected by glslangValidator:

$ glslangValidator -V100 --spirv-val -S frag -D --target-env vulkan1.0 input.frag.hlsl -e main
/tmp/input.frag.hlsl
error: SPIRV-Tools Validation Errors
error: Expected Image Operand Bias to be float scalar
  %40 = OpImageSampleImplicitLod %v4float %39 %23 Bias|ConstOffset %27 %float_0