XYZ encountered an error and has been disabled + SyntaxTree is not part of the compilation

Somehow the Mediator generator has stopped working on my machine on visual studio 2022 17.6.0 and later versions. Possibly this only happened after an update previously, I am not sure. Everything still works on Rider, so clearly it is something to do with the interaction with the Mediator codegen and visual studio. Can you advise what I can do to diagnose this further?

When I open the solution, I see a lot of “XYZ encountered an error and has been disabled” messages at the top of visual studio. These XYZ are related to various parts of the RefactoringProvider and all have the exception trace as shown below. I also see some features with the same issue and stack trace (CodeLens references … ).

If I remove the Mediator code generator from the solution I do not see any of these issues, but obviously, I can’t initialise the mediator, so nothing works in a useful way.

If I look at the IncrementalMediatorGenerator Analyzer in solution explorer, the spinning wheel continues forever, but nothing is generated.

I have tried reinstalling visual studio and rebooting and disabling resharper … any other suggestions?

StreamJsonRpc.RemoteInvocationException: SyntaxTree is not part of the compilation (Parameter ‘syntaxTree’) at StreamJsonRpc.JsonRpc.<InvokeCoreAsync>d__1511.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Threading.Tasks.ValueTask1.get_Result() at Microsoft.CodeAnalysis.Remote.BrokeredServiceConnection1.<TryInvokeAsync>d__181.MoveNext() RPC server exception: System.ArgumentException: SyntaxTree is not part of the compilation (Parameter ‘syntaxTree’) at Microsoft.CodeAnalysis.CSharp.CSharpCompilation.GetSemanticModel(SyntaxTree syntaxTree, Boolean ignoreAccessibility) at Microsoft.CodeAnalysis.CSharp.CSharpCompilation.CommonGetSemanticModel(SyntaxTree syntaxTree, Boolean ignoreAccessibility) at Microsoft.CodeAnalysis.Diagnostics.SuppressMessageAttributeState.IsDiagnosticSuppressed(Diagnostic diagnostic, SuppressMessageInfo& info) at Microsoft.CodeAnalysis.Diagnostics.SuppressMessageAttributeState.ApplySourceSuppressions(Diagnostic diagnostic) at Microsoft.CodeAnalysis.GeneratorDriver.FilterDiagnostics(Compilation compilation, ImmutableArray1 generatorDiagnostics, DiagnosticBag driverDiagnostics, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.GeneratorDriver.RunGeneratorsCore(Compilation compilation, DiagnosticBag diagnosticsBag, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.GeneratorDriver.RunGenerators(Compilation compilation, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.FinalizeCompilationAsync(SolutionState solution, Compilation compilationWithoutGenerators, CompilationTrackerGeneratorInfo generatorInfo, Compilation compilationWithStaleGeneratedTrees, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.BuildCompilationInfoFromScratchAsync(SolutionState solution, CompilationTrackerGeneratorInfo generatorInfo, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.BuildCompilationInfoAsync(SolutionState solution, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.GetOrBuildCompilationInfoAsync(SolutionState solution, Boolean lockGate, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.GetCompilationSlowAsync(SolutionState solution, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.GetMetadataReferenceAsync(ICompilationTracker tracker, ProjectState fromProject, ProjectReference projectReference, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.FinalizeCompilationAsync(SolutionState solution, Compilation compilationWithoutGenerators, CompilationTrackerGeneratorInfo generatorInfo, Compilation compilationWithStaleGeneratedTrees, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.BuildCompilationInfoFromScratchAsync(SolutionState solution, CompilationTrackerGeneratorInfo generatorInfo, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.BuildCompilationInfoAsync(SolutionState solution, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.GetOrBuildCompilationInfoAsync(SolutionState solution, Boolean lockGate, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.SolutionState.CompilationTracker.GetCompilationSlowAsync(SolutionState solution, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.Razor.TagHelperResolver.GetTagHelpersAsync(Project workspaceProject, RazorProjectEngine engine, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.Remote.Razor.RemoteTagHelperProviderService.GetTagHelpersCoreAsync(RazorPinnedSolutionInfoWrapper solutionInfo, ProjectSnapshotHandle projectHandle, String factoryTypeName, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.Remote.Razor.RemoteTagHelperProviderService.GetTagHelpersDeltaCoreAsync(RazorPinnedSolutionInfoWrapper solutionInfo, ProjectSnapshotHandle projectHandle, String factoryTypeName, Int32 lastResultId, CancellationToken cancellationToken) at Microsoft.CodeAnalysis.Remote.BrokeredServiceBase.RunServiceImplAsync[T](Func2 implementation, CancellationToken cancellationToken)

[martinothamar]

Great, I’m publishing the bugfix in version 2.1.2 as well: https://www.nuget.org/packages/Mediator.SourceGenerator/2.1.2 I’ll revisit the “correct” location in a future refarctoring, as there are some big changes to the source generation process coming up

[panoukos41]

Hey thanks for the investigation, I wanted to dig too but didnt have as much time and restarting VS doesn’t help 😛, I am happy the requests I left for later actually helped!!

It works as expected now, thanks again 😄 !!