anchor.diff:  open System
   open Microsoft.VisualStudio.TestTools.UnitTesting
   open FsControl.Operators
  +
  +type MonadBuilder() =
  +    member inline b.Return(x)    = result x
  +    member inline b.Bind(p,rest) = p >>= rest
  +    member        b.Let (p,rest) = rest p
  +    member    b.ReturnFrom(expr) = expr
   
   module Combinators =
       let inline flip f x y = f y x
  
positive.code:         let s' = sortBy id s
          Assert.AreEqual (l', [4;6;10;89])
          Assert.AreEqual (s', WrappedListB [4;6;10;89])
  
  
  [<TestClass>]
  
negative.code:     let inline (/>) x = flip x
      let inline choice f g = function Choice2Of2 x -> f x | Choice1Of2 y -> g y
      let inline option n f = function None -> n | Some x -> f x
      let monad     = new MonadBuilder()
  open Combinators
  
  
  type WrappedListA<'s> = WrappedListA of 's list with
  