Annoying assertion when typing code

[cartermp]

In a hive, type something like:

let z = 

Eventually, you'll see something like this:

---------------------------
Assertion Failed: Abort=Quit, Retry=Debug, Ignore=Continue
---------------------------
   at Microsoft.FSharp.Compiler.ErrorLogger.newIsInstalled@450.Invoke(Unit unitVar0)
   at Microsoft.FSharp.Compiler.ErrorLogger.chkErrorLogger@451.DiagnosticSink(PhasedDiagnostic phasedError, Boolean isError)
   at Microsoft.FSharp.Compiler.LexFilter.LexFilterImpl.pushCtxt(TokenTup tokenTup, Context newCtxt)
   at Microsoft.FSharp.Compiler.LexFilter.LexFilterImpl.hwTokenFetch(Boolean useBlockRule)
   at Microsoft.FSharp.Compiler.LexFilter.loop@2262-33.Invoke(Unit unitVar0)
   at Microsoft.FSharp.Compiler.SourceCodeServices.Parser.createLexerFunction@1485.Invoke(a arg00)
   at Microsoft.FSharp.Compiler.SourceCodeServices.Parser.matchBraces@1513-1.Invoke(FSharpList`1 stack)
   at Microsoft.FSharp.Compiler.Lexhelp.reusingLexbufForParsing[a](LexBuffer`1 lexbuf, FSharpFunc`2 f)
   at Microsoft.FSharp.Compiler.Lexhelp.usingLexbufForParsing[a](LexBuffer`1 lexbuf, String filename, FSharpFunc`2 f)
   at Microsoft.FSharp.Compiler.SourceCodeServices.Parser.matchBraces(String source, String fileName, FSharpParsingOptions options, String userOpName)
   at <StartupCode$FSharp-Compiler-Private>.$Service.MatchBraces@2853.Invoke(Unit unitVar)
   at Microsoft.FSharp.Control.AsyncBuilderImpl.callA@522.Invoke(AsyncParams`1 args)
   at <StartupCode$FSharp-Core>.$Control.loop@125-37.Invoke(FSharpFunc`2 action)
   at Microsoft.FSharp.Control.Trampoline.ExecuteAction(FSharpFunc`2 firstAction)
   at Microsoft.FSharp.Control.TrampolineHolder.Protect(FSharpFunc`2 firstAction)
   at Microsoft.FSharp.Control.TaskHelpers.continuation@1184.Invoke(Task`1 completedTask)
   at Microsoft.FSharp.Control.TaskHelpers.continueWith@1194.Invoke(Task`1 delegateArg0)
   at System.Threading.Tasks.ContinuationTaskFromResultTask`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
   at System.Threading.Tasks.Task.ExecutionContextCallback(Object obj)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot)
   at System.Threading.Tasks.Task.ExecuteEntry(Boolean bPreventDoubleExecution)
   at System.Threading.Tasks.Task.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()
---------------------------
Abort   Retry   Ignore   
---------------------------

I have no idea what could be causing this.

[cartermp]

It also seems to leave the editor in a somewhat broken state. Auto de-indentation doesn't work once this gets hit.

[dsyme]

Looking at this code, something in brace matching is using an error logger after it has been deactivated.

It's likely to be from this

        use unwindBP = PushThreadBuildPhaseUntilUnwind BuildPhase.Parse
        use unwindEL = PushErrorLoggerPhaseUntilUnwind (fun _ -> DiscardErrorsLogger)

It may be harmless in this case because DiscardErrorsLogger carries no state, I'm not sure

@auduchinok I think this may be related to your PR for parsing on non-compiler threads - could you take a look?

[auduchinok]

@dsyme I'll take a look.

[cartermp]

I'm noticing this on a VSIX built on my install from release\net40\bin\VisualFSharpOpenSource.vsix. It's making constructing records intances basically impossible.

[vasily-kirichenko]

It makes typing any code impossible. I've tested in release for a while.

[cartermp]

Yeah, I noticed that it's basically anything where you hit space or enter after a token, or > following a -. Since it seems to be coming from the call stack, is this also present in Rider?