Odd compiliation error with ResourceDescriptorHeap and type deduction

struct PSInput
{
	float4 color : COLOR;
};

float4 PSMain(PSInput input) : SV_TARGET
{
	return ((StructuredBuffer<float>)ResourceDescriptorHeap[int(input.color.x)]).Load(0);
}

https://shader-playground.timjones.io/27ac5c864a447a7014ae267711a86d4a

Error:

D:\local\Temp\178b99bf-6e48-4e9f-88b4-102b65301c33.hlsl:8:79: error: no member named 'Load' in 'StructuredBuffer<float>'
        return ((StructuredBuffer<float>)ResourceDescriptorHeap[int(input.color.x)]).Load(0);
               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^

Somehow the right type is deduced, but we can't call it's functions?

Start with the HLSL repro in the issue and the linked Shader Playground result, focusing on ResourceDescriptorHeap indexing, the StructuredBuffer cast, and member lookup for Load. Trace the compiler path that handles this expression and add or run a regression test; done means the repro compiles with the expected Load behavior or produces a correct diagnostic.