anchor.diff:  
       static let oneColAfter (lp: LinePosition) = LinePosition(lp.Line,lp.Character+1)
       static let oneColBefore (lp: LinePosition) = LinePosition(lp.Line,max 0 (lp.Character-1))
  +
  +    let mutable possibleCurrentSignatureHelpSessionKind = None
   
       static member internal ProvideMethodsAsyncAux
           (
  
positive.code:       Parameters: SignatureHelpParameterInfo[]
        MainDescription: ResizeArray<RoslynTaggedText> }
  
  type SignatureHelpData =
      { SignatureHelpItems: SignatureHelpItem[]
        ApplicableSpan: TextSpan
        ArgumentIndex: int
        ArgumentCount: int
        ArgumentName: string option }
  
  [<Shared>]
  [<Export(typeof<IFSharpSignatureHelpProvider>)>]
  
negative.code:             options: FSharpProjectOptions,
              filePath: string,
              textVersionHash: int,
              triggerTypedChar: char option,
              possibleCurrentSignatureHelpSessionKind: CurrentSignatureHelpSessionKind option
          ) =
          asyncMaybe {
              let textLines = sourceText.Lines
  