directx – Specifying a root signature in the HLSL code of a DXR shader

I’ve noticed that I cannot specify a root signature in the HLSL code of a DXR shader. For example, if I got a ray generation shader with the following declaration

(rootsignature(
    "RootFlags(LOCAL_ROOT_SIGNATURE),"  
    "DescriptorTable("                  
    "UAV(u0, numDescriptors = 1),"  
    "SRV(t0, numDescriptors = 1))"))
(shader("raygeneration"))
void RayGen()
{}

CreateRootSignature yields the error message

No root signature was found in the dxil library provided to CreateRootSignature. ( STATE_CREATION ERROR #696: CREATE_ROOT_SIGNATURE_BLOB_NOT_FOUND).

I’ve noticed that even when I add a typo (for example, write roosignature instead of rootsignature), the compiler doesn’t complain about this typo. So, it seems like the whole attribute declaration is simply ignored.

If I change the code to a simple rasterization shader, everything works as expected.

So, is the specification of a root signature in the HLSL code of a DXR shader not supported?