anchor.diff:                          let entries = cfe.Entries |> List.ofSeq
                           entries, state', varsSet
                       // not implemented (but must precede IReferenceExpression case)
  -                    | :? IInvocationExpression -> 
  +                    | :? IInvocationExpression as invocExpr -> 
                           cfe.Entries |> List.ofSeq, state, varsSet
                       | :? IReferenceExpression as refExpr 
                           when Set.contains cfe.Id state.RefExprsToVisit 
  
positive.code:             else cfgNodes |> List.ofSeq |> List.head
  
          let rec build (cfe: IControlFlowElement) (varsSet: Set<string>) (state: BuildState) =
              let (|AppropNameAssignExpr|_|) (node: ITreeNode) =
                  match node with
                  | :? IAssignmentExpression as assignExpr 
                      when 
  
negative.code:                 | _ ->
                      let astNode = cfe.SourceElement
                      match astNode with
                      | TrackedVarAssignExpr(assignExpr) -> 
                          let assingnType, operands = 
                              if assignExpr.AssignmentType = AssignmentType.EQ
                              then 
  