anchor.diff:          member this.ReturnFrom (p: Form<_, _ -> _>) = p
   
           [<Inline>]
  -        member this.Yield x = Yield x
  +        member this.Yield init = Yield init
   
           [<Inline>]
           member this.YieldFrom (p: Form<_, _ -> _>) = p
  
positive.code:         MapResult (fun x -> f x; x) p
  
      [<JavaScript>]
      let ManyForm inits create p =
          let m = Many.Collection(p, inits, create)
          {
              id = Fresh.Id()
              view = m.View
  
negative.code:             | Success (Failure mx) -> Failure mx
              | Success (Success x) -> Success (f x)
  
      static member Bind (f: 'T -> Result<'U>) (r: Result<'T>) : Result<'U> =
          match r with
          | Failure m -> Failure m
          | Success x -> f x
  
  