anchor.diff:                  do printfn "No support for interface files"
           | FailedWith error -> 
               do Console.WriteLine error
  -
  
positive.code: 
      let visitPattern pattern = printf "pattern"
      
      let visitExpression expr = printf "expr"
      
      let rec typeToString = function
      | SynType.LongIdent (ident) -> identToString ident  
  
negative.code:                         printf " : %s" (typeToString synType)
                      | None -> ()
                      do printf " = "
                      do visitExpression body |> ignore
                      printfn ""
                  // do printfn "%A" bindings
              | SynModuleDecl.Open(longIdentWithDots, range) ->
                  do printfn "open %s" (identToString longIdentWithDots)
                  
              | SynModuleDecl.DoExpr(sequencePointInfo, expression, range) ->
                  do visitExpression expression |> ignore
                  do printfn "with sequence point info %A" sequencePointInfo
              | _ -> ()
  
  