[wasm][R2R] variant static interface dispatch has signature mismatch

[lewing]

Description

Loader/classloader/StaticVirtualMethods/InterfaceVariance/ComplexHierarchyPositive traps during variant static-interface dispatch in the browser-wasm CoreCLR ReadyToRun lane.

Reproduction Steps

Run the runtime-wasm-non-libtests pipeline with ReadyToRun tests enabled on dotnet/runtime commit ef1850bdc9e7d142888247d9bb5df3b74a7ae341 (Azure DevOps build 1588226, Helix job 2a25b357-0ff1-40a2-9fe9-5e205f73cb27, work item Loader).

Expected behavior

ComplexHierarchyPositive completes its variant static-interface dispatch checks.

Actual behavior

Running test: Loader/classloader/StaticVirtualMethods/InterfaceVariance/ComplexHierarchyPositive/ComplexHierarchyPositive.dll
Test cases
---FooBar
TestTheFooString FooBar Base IFoo<Base>
RuntimeError: null function or function signature mismatch
    at ComplexHierarchyPositive_VariantStaticInterfaceDispatchRegressionTest_Test__GetTheFooStringInstance<System___Canon__System___Canon>
    at WasmInterpreterToR2RThunk(iip)
    at WasmR2RToInterpreterThunk(viip)
    at WasmDelayLoadHelper->EagerImports->SignaturePointer_ReadyToRunHelper_DelayLoad_MethodCall

Regression?

Unknown. This was reproduced on current main during the #133305 census.

Known Workarounds

Skip only this test method for browser CoreCLR ReadyToRun. Mono, WASI, non-browser, and non-R2R coverage remain enabled.

Configuration

• dotnet/runtime commit ef1850bdc9e7d142888247d9bb5df3b74a7ae341
• CoreCLR browser-wasm
• Checked runtime
• ReadyToRun / crossgen2
• Node.js 23.11.1

Other information

Tracking issue: #133305.

Note

This issue was authored with GitHub Copilot.

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Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
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[AndyAyersMS]

Seems like a problem with ensuring that methods resolved in VirtualCallStubManager::Resolver are callable from R2R.

Crossgen2’s Wasm-specific  CORINFO_VIRTUALCALL_LDVIRTFTN  branch in  CorInfoImpl.ReadyToRun.cs  bypasses the normal interface-dispatch logic that sets  useInstantiatingStub  for default-interface methods.

@davidwrighton do you want to take this one?