TMI when passing an invalid commandline option to FSI.exe

[abelbraaksma]

We show a full stacktrace whenever you pass a wrong commandline option. That isn't very neat, I think we ought to just print the error instead.

This is current:

error FS0243: Unrecognized option: '--version'

Exception by fsi.exe:
System.Exception: Error creating evaluation session: StopProcessingExn None
   at Microsoft.FSharp.Core.PrintfModule.PrintFormatToStringThenFail@1639.Invoke(String message)
   at FSharp.Compiler.Interactive.Shell.FsiCommandLineOptions..ctor(FsiEvaluationSessionHostConfig fsi, String[] argv, TcConfigBuilder tcConfigB, FsiConsoleOutput fsiConsoleOutput)
   at FSharp.Compiler.Interactive.Shell.FsiEvaluationSession..ctor(FsiEvaluationSessionHostConfig fsi, String[] argv, TextReader inReader, TextWriter outWriter, TextWriter errorWriter, Boolean fsiCollectible, FSharpOption`1 legacyReferenceResolver)
   at FSharp.Compiler.Interactive.Shell.FsiEvaluationSession.Create(FsiEvaluationSessionHostConfig fsiConfig, String[] argv, TextReader inReader, TextWriter outWriter, TextWriter errorWriter, FSharpOption`1 collectible, FSharpOption`1 legacyReferenceResolver)
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.LazyInitValue()
   at System.Lazy`1.get_Value()
   at Sample.FSharp.Compiler.Interactive.Main.evaluateSession(String[] argv)

Expected:

error FS0243: Unrecognized option: '--version'

Or even better, we can dump the --help screen whenever an invalid commandline is passed, or a simple line saying "use --help for help".

[cartermp]

Yep, this can be improved

[KevinRansom]

You know, nearly every time I see the error trace, I think, dang we should fix that. Then get back to work.

[abelbraaksma]

@vzarytovskii, you moved this to Not planned, but it has meanwhile been fixed 🥳 . I'll adjust status accordingly. Screenshot is from current RTM.

[vzarytovskii]

Sure, but please don't add or change any impact labels, those are for internal use only.