anchor.diff:      ctx.FieldExecuteMap.SetExecute("Data", fieldDef)
       next ctx
   
  -// After the schema has been compiled, inject a fake variable "foo" to every input object
  +// After the schema has been compiled, update the input fields to flip every boolean input
   let postCompileMiddleware (schema : ISchema) (next : ISchema -> unit) =
  +    let flipBools execute value vars =
  +        match value with
  +        | BooleanValue b -> execute (BooleanValue (not b)) vars
  +        | _ -> execute value vars
       schema.TypeMap.ToSeq()
       |> Seq.iter(fun (n, def) ->
                       match def with
                       | InputObject iobj ->
                           iobj.Fields
  -                        |> Array.iter(fun f -> f.ExecuteInput <- (fun value vars -> f.ExecuteInput value (Map.add "foo" (upcast 1) vars)))
  +                        |> Array.iter(fun f -> f.ExecuteInput <- (flipBools f.ExecuteInput))
                       | _ -> ())
       next schema
   
  
positive.code:                     upcast NameValueLookup.ofList 
                          [ "a", upcast "Cookie" 
                            "b", upcast "Banana"
                            "hasFoo", upcast true ] ]
      match result with
      | Direct (data, errors) ->
          empty errors
  
negative.code:             a
              b
              c
              d(input : true )
          }
      }"""
  
  