anchor.diff:  open Newtonsoft.Json.Serialization
   
   open WpfMath
  +open WpfMath.Atoms
   
   type private BomlessFileWriter(data: string, ?extensionWithoutDot: string) =
       inherit ApprovalTextWriter(data, defaultArg extensionWithoutDot "txt")
  
positive.code:                             member this.SetValue(_, _) = failwith "Not supported"
                      }
                  )
              )
          upcast properties
  
  [<AbstractClass>]
  type ReadOnlyJsonConverter<'a>() =
  
negative.code:         base.CreateProperty(p, ms, Readable = true)
  
      override this.CreateProperties(``type``, memberSerialization) =
          // All properties including internal ones:
          let properties =
              ``type``.GetProperties(BindingFlags.Public ||| BindingFlags.NonPublic ||| BindingFlags.Instance)
              |> Seq.filter (fun p -> Array.isEmpty <| p.GetIndexParameters()) // no indexers
              |> Seq.map (fun p -> this.DoCreateProperty(p, memberSerialization))
  
          upcast [|
              // For Atoms, type name should be first
              if typeof<Atom>.IsAssignableFrom ``type`` then
                  JsonProperty(
                      PropertyName = "[AtomType]",
                      PropertyType = typeof<string>,
                      Readable = true,
  