Version Used:
Compiler version: '3.10.0-4.21269.26 (0298477)'. Language version: 8.0.
SDK Version:
$ dotnet --info
.NET SDK (reflecting any global.json):
Version: 6.0.100-preview.3.21202.5
Commit: aee38a6dd4
Steps to Reproduce:
Have a namespace not matching the folder structure. Stack trace:
System.InvalidOperationException : This Workspace does not support changing a document's Folders.
at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioWorkspaceImpl.FailIfDocumentInfoChangesNotSupported(Document document,DocumentInfo updatedInfo)
at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioWorkspaceImpl.ApplyDocumentInfoChanged(DocumentId documentId,DocumentInfo updatedInfo)
at Microsoft.CodeAnalysis.Workspace.ApplyChangedDocument(ProjectChanges projectChanges,DocumentId documentId)
at Microsoft.CodeAnalysis.Workspace.ApplyProjectChanges(ProjectChanges projectChanges)
at Microsoft.CodeAnalysis.Workspace.TryApplyChanges(Solution newSolution,IProgressTracker progressTracker)
at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioWorkspaceImpl.TryApplyChanges(Solution newSolution,IProgressTracker progressTracker)
at Microsoft.CodeAnalysis.CodeActions.ApplyChangesOperation.TryApply(Workspace workspace,IProgressTracker progressTracker,CancellationToken cancellationToken)
at Microsoft.CodeAnalysis.Editor.Implementation.CodeActions.CodeActionEditHandlerService.ProcessOperations(Workspace workspace,ImmutableArray`1 operations,IProgressTracker progressTracker,CancellationToken cancellationToken)
at Microsoft.CodeAnalysis.Editor.Implementation.CodeActions.CodeActionEditHandlerService.Apply(Workspace workspace,Document fromDocument,ImmutableArray`1 operations,String title,IProgressTracker progressTracker,CancellationToken cancellationToken)
at Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction.InvokeWorker(Func`1 getFromDocument,IProgressTracker progressTracker,CancellationToken cancellationToken)
at Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction.<>c__DisplayClass22_0.<InvokeCore>b__0()
at Microsoft.CodeAnalysis.Extensions.IExtensionManagerExtensions.PerformAction(IExtensionManager extensionManager,Object extension,Action action)
at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
Note: the crash happens on applying the change, but the preview shows a change without crash.
Note 2: the change suggested is actually incorrect (note the "expected" part in the diagnostic message, it's correct, but the suggestion isn't the same).

cc @ryzngard
Version Used:
Compiler version: '3.10.0-4.21269.26 (0298477)'. Language version: 8.0.
SDK Version:
Steps to Reproduce:
Have a namespace not matching the folder structure. Stack trace:
Note: the crash happens on applying the change, but the preview shows a change without crash.
Note 2: the change suggested is actually incorrect (note the "expected" part in the diagnostic message, it's correct, but the suggestion isn't the same).
cc @ryzngard