[SPIRV] OpAccessChain storage class mismatch when accessing resource member in struct array

When compiling HLSL that creates an array of structs with resource members and accesses them via constant indexing, DXC's SPIRV backend generates invalid SPIR-V:

fatal error: generated SPIR-V is invalid: The result pointer storage class and base pointer storage class in OpAccessChain do not match. %13 = OpAccessChain %_ptr_Uniform_uint %gBuf %uint_0 %uint_0

Repro:

RWByteAddressBuffer gBuf : register(u0);

struct BufStruct { RWByteAddressBuffer buf; };

[numthreads(1,1,1)] 
void main() {  
BufStruct s[2];  
s[0].buf = gBuf;
s[0].buf.Store(0, 42); 
}

Command:

dxc.exe -spirv -fspv-target-env=vulkan1.3 -T cs_6_0 -Fo out.spv repro.hlsl

https://godbolt.org/z/cqj4j1zzb

DXC DXIL compiles and runs this correctly. DXC version: main (built from source).

Start by running the provided HLSL reproducer with dxc.exe using the shown SPIR-V command, then trace the SPIR-V backend handling of OpAccessChain for resource members in struct arrays. Done means the reproducer compiles without the storage-class validation error and the generated SPIR-V is valid.