anchor.diff:  [<JavaScript>]
   [<Require(typeof<Resource>)>]
   let Activate<'T> (json: obj) : 'T =
  -    let types : obj[] = json?("$TYPES")
  +    let types = As<obj[]> ((?) json "$TYPES")
       for i = 0 to types.Length - 1 do
           types.[i] <- lookup (As types.[i])
       let rec decode (x: obj) : obj =
  
positive.code:             r <- rn
              i <- i + 1
          else
              // The class is not present on the client,
              // it could have been pruned by the bundling.
              r <- JS.Undefined
              i <- k
      r
  
  /// Does a shallow generic mapping over an object.
  
negative.code:                 if JS.InstanceOf x JS.Global?Array then
                      shallowMap decode x
                  else
                      let o  = shallowMap decode ((?) x "$V")
                      let ti = (?) x "$T"
                      if JS.TypeOf ti = JS.Kind.Undefined then o else
                          let r = JS.New types.[ti]
                          JS.ForEach o (fun k -> (?<-) r k ((?) o k); false)
                          r
              | _ ->
                  x
      As (decode ((?) json "$DATA"))
  
  