SamplerDescriptorHeap[sampIdx] cannot be used inside of texture.Sample(...)

The following is a sample from this document: https://microsoft.github.io/DirectX-Specs/d3d/HLSL_SM_6_6_DynamicResources.html

Texture2D<float4> myTexture = ResourceDescriptorHeap[texIdx];
float4 result = myTexture.Sample(SamplerDescriptorHeap[sampIdx], coord);

But in practice (with the December 2021 release), doing this results in compilation errors:

MyShader.hlsl: error: no matching member function for call to 'Sample'
float4 result  = myTexture.Sample(SamplerDescriptorHeap[sampIdx], coord);
                   ~~~~~~~~~~~~~^~~~~~
note: candidate function template not viable: requires 3 arguments, but 2 were provided
note: candidate function template not viable: requires 4 arguments, but 2 were provided
note: candidate function template not viable: requires 5 arguments, but 2 were provided

Creating a separate SamplerState variable to store it and then using that works, casting within the Sample function like this also works:

myTexture.Sample(((SamplerState)SamplerDescriptorHeap[sampIdx]), coord);

Presumably some confusion between SamplerState and SamplerComparisonState, but since these use Sample() and SampleCmp() respectively, we might still expect it to just work.

Thank you for your time!

Start with the MyShader.hlsl reproducer from the DirectX HLSL dynamic-resources document and compile it using the December 2021 release. Investigate why SamplerDescriptorHeap[sampIdx] is rejected as the first argument to Sample while a separate SamplerState or explicit cast works; done means the documented two-argument form compiles successfully.