The function returns E_INVALIDARG. I'm trying to call this with a compiled shader (ie the resulting blob from D3DCompileFromFile). I'm not specifying the RootSignature in the HLSL directly, I'm creating it in the C++ code and passing it to the pipeline state.
Seeing as misaligning the root signature on purpose causes an error telling me I'm binding the wrong descriptor table type (for example), it seems like the implicit root signature in the compiled shader is known. How do I get it via reflection?