[SPIR-V] Crash observed while processing TraceRay intrinsic when the payload argument is a MemberExpr

Description
We observed a crash in DXC compiling lib6_6 raytracing code to SpirV. The crash happens in the SpirvEmitter.cpp:13780 after this codeblock:

  if (const auto *implCastExpr = dyn_cast<CastExpr>(args[7])) {
    if (const auto *arg = dyn_cast<DeclRefExpr>(implCastExpr->getSubExpr())) {
      if (const auto *varDecl = dyn_cast<VarDecl>(arg->getDecl())) {
        rayPayloadType = varDecl->getType();
        rayPayloadArg = varDecl;
        const auto rayPayloadPair = rayPayloadMap.find(rayPayloadType);
        // Check if same type of rayPayload stage variable was already
        // created, if so re-use
        if (rayPayloadPair == rayPayloadMap.end()) {
          int numPayloadVars = rayPayloadMap.size();
          rayPayloadStageVar = declIdMapper.createRayTracingNVStageVar(
              spv::StorageClass::RayPayloadNV, varDecl);
          // Decorate unique location id for each created stage var
          spvBuilder.decorateLocation(rayPayloadStageVar, numPayloadVars);
          rayPayloadLocInst = spvBuilder.getConstantInt(
              astContext.UnsignedIntTy, llvm::APInt(32, numPayloadVars));
          rayPayloadMap[rayPayloadType] =
              std::make_pair(rayPayloadStageVar, rayPayloadLocInst);
        } else {
          rayPayloadStageVar = rayPayloadPair->second.first;
          rayPayloadLocInst = rayPayloadPair->second.second;
        }
      }
    }
  }

  assert(rayPayloadStageVar && rayPayloadArg);

In debug builds, the assert fires.

Steps to Reproduce
Here is a minimal HLSL repro snipped

RaytracingAccelerationStructure Scene : register(t0);

struct MyPayload
{
    uint hit;
    float t;
};

struct SomeType
{
    MyPayload rayPayload;
};

[shader("raygeneration")]
void RayGen()
{
    SomeType InstanceOfSomeType;

    // Initialize payload
    InstanceOfSomeType.rayPayload.hit = 0;
    InstanceOfSomeType.rayPayload.t = -1.0f;

    RayDesc ray;
    ray.Origin = float3(0.0f, 0.0f, 0.0f);
    ray.Direction = float3(0.0f, 0.0f, 1.0f);
    ray.TMin = 0.0f;
    ray.TMax = 1.0e38f;

    // Payload passed as a MEMBER EXPRESSION (inout)
    TraceRay(
        Scene,
        RAY_FLAG_NONE,
        0xFF, // InstanceInclusionMask
        0, // RayContributionToHitGroupIndex
        1, // MultiplierForGeometryContributionToHitGroupIndex
        0, // MissShaderIndex
        ray,
        InstanceOfSomeType.rayPayload //  <--------------------------- This MemberExpr causes a crash/assert in SpirvEmitter
    );
}

[shader("miss")]
void Miss(inout MyPayload payload)
{
    payload.hit = 0;
    payload.t = -1.0f;
}

[shader("closesthit")]
void ClosestHit(inout MyPayload payload, in BuiltInTriangleIntersectionAttributes attribs)
{
    payload.hit = 1;
    payload.t = RayTCurrent();
}

command line: dxc.exe -T lib_6_6 -spirv repo.hlsl

Actual Behavior
Internal Compiler error (the assert shown above terminates the compilation).

Environment

• DXC version 1.10(5194-4687c52d)(1.9.0.15194) - 1.9.0.15194 (main, 4687c52d6)
• Host Operating System Windows 11 24h2

Start with SpirvEmitter.cpp around line 13780 and run the supplied minimal HLSL repro with dxc.exe -T lib_6_6 -spirv repo.hlsl. TraceRay receives a MemberExpr payload, so inspect the shown payload-handling path and its assertion. Done means the repro compiles without the internal compiler error or debug assertion.