[WASM] VTable setup of type Windows.UI.Xaml.ObservableVectorListWrapper failed

[jeromelaban]

Note: I tried to create a repo sample, but with the exact same hierarchy that fails in the solution, the repro does not.

Steps to Reproduce

1. Clone this solution at commit unoplatform/Uno.Xaml-Controls-Gallery@f1be090.
2. In the folder XamlControlsGallery.Wasm, under linux run msbuild /r

Current Behavior

LLVM fails to compile with the following error:

[227/258] [AOT] ./linker-out/Uno.UI.dll -> ./Uno.UI.dll.bc
  Unable to compile method 'Windows.Foundation.Collections.IObservableVector`1<object> Windows.UI.Xaml.ObservableVectorWrapper:Create (object)' due to: 'VTable setup of type Windows.UI.Xaml.ObservableVectorListWrapper failed assembly:/home/nvdevops/vsts.agent01/_work/2/s/XamlControlsGallery.Wasm/obj/Release/netstandard2.0/workAot/linker-out/Uno.UI.dll type:ObservableVectorListWrapper member:(null)'.
  Mono Ahead of Time compiler - compiling assembly /home/nvdevops/vsts.agent01/_work/2/s/XamlControlsGallery.Wasm/obj/Release/netstandard2.0/workAot/linker-out/Uno.UI.dll
  AOTID 30D1EF30-CAAB-8D70-B63E-1882FCAE31A9
  Compiled: 15884/15885
  Output file: '/tmp/mono_aot_aswc2B'.
  Linking symbol: 'mono_aot_module_Uno_UI_info'.
  LLVM output file: './Uno.UI.dll.bc'.
  JIT time: 3190 ms, Generation time: 1812 ms, Assembly+Link time: 0 ms.

Expected Behavior

The assembly is built properly.

On which platforms did you notice this

[ ] macOS
[ ] Linux
[ ] Windows
[x] WebAssembly

Version Used: 5f65ce9

[vargaz]

This is a linker problem, it removes the
ObservableVectorWrapper::add_VectorChanged method, which is needed by a subclass (ObservableVectorEnumerableWrapper) to implement the IObservableVector interface.

[vargaz]

dotnet/linker#465

[kjpou1]

@jeromelaban is this now working?

[jeromelaban]

This is fixed in latest mono, most probably due to an update of the linker. Thanks!