Error "Symbol's project could not be found in the provided solution"

[Dreamescaper]

Version Used:
VS 16.7 Preview 1

Steps to Reproduce:

Cannot find so far, will update once find out.

Expected Behavior:
(no errors)

Actual Behavior:

StreamJsonRpc.RemoteInvocationException : Symbol's project could not be found in the provided solution
   at async StreamJsonRpc.JsonRpc.InvokeCoreAsync[TResult](<Unknown Parameters>)
   at async Microsoft.CodeAnalysis.Remote.RemoteEndPoint.InvokeAsync[T](<Unknown Parameters>)
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
---> (Remote Exception) {
  "type": "System.InvalidOperationException",
  "message": "Symbol's project could not be found in the provided solution",
  "stack": "   at Roslyn.Utilities.Contract.Fail(String message)\r\n   at Microsoft.CodeAnalysis.FindSymbols.SymbolFinder.<FindReferencesAsync>d__30.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.CodeAnalysis.DocumentHighlighting.AbstractDocumentHighlightsService.<GetTagsForReferencedSymbolAsync>d__4.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.CodeAnalysis.DocumentHighlighting.AbstractDocumentHighlightsService.<GetDocumentHighlightsInCurrentProcessAsync>d__1.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)\r\n   at Microsoft.CodeAnalysis.DocumentHighlighting.AbstractDocumentHighlightsService.<GetDocumentHighlightsAsync>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.CodeAnalysis.Remote.CodeAnalysisService.<>c__DisplayClass12_0.<<GetDocumentHighlightsAsync>b__0>d.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.CodeAnalysis.Remote.ServiceBase.<RunServiceAsync>d__13`1.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)",
  "code": -2146233079,
  "inner": null
} <--- 

[Dreamescaper]

Seems to be related to #44399, but I don't have discards in file, where I have this issue.

[CyrusNajmabadi]

This was fixed. I'll find and close out.

[CyrusNajmabadi]

Fixed with #44467, #44265, #44713