anchor.diff:          (retype trueMap), (retype falseMap)
   
       //
  +    [<CompiledName("OfSeq")>]
  +    let inline ofSeq (sequence : seq<int<'Tag> * 'T>) : TagBimap<'Tag, 'T> =
  +        // Preconditions
  +        checkNonNull "sequence" sequence
  +
  +        IntBimap<_>.OfSeq (retype sequence)
  +        |> retype
  +
  +    //
       [<CompiledName("OfList")>]
       let inline ofList (list : (int<'Tag> * 'T) list) : TagBimap<'Tag, 'T> =
           // Preconditions
  
positive.code:         |> retype
  
      //
      [<CompiledName("OfArray")>]
      let inline ofArray (array : (int<'Tag> * 'T)[]) : TagBimap<'Tag, 'T> =
          // Preconditions
          checkNonNull "array" array
  
          IntBimap<_>.OfArray (retype array)
          |> retype
  
      //
      [<CompiledName("ToArray")>]
      let inline toArray (bimap : TagBimap<'Tag, 'T>) : (int<'Tag> * 'T)[] =
          // Retype as IntBimap.
  
negative.code:         |> retype
  
      //
      [<CompiledName("OfArray")>]
      let inline ofArray (array : (int<'Tag> * 'T)[]) : TagBimap<'Tag, 'T> =
          // Preconditions
          checkNonNull "array" array
  
          IntBimap<_>.OfArray (retype array)
          |> retype
  
      //
      [<CompiledName("ToSeq")>]
      let inline toList (bimap : TagBimap<'Tag, 'T>) : seq<int<'Tag> * 'T> =
          // Retype as IntBimap.
          let bimap : IntBimap<'T> = retype bimap
  
          // Preconditions
          checkNonNull "bimap" bimap
  
          bimap.ToSeq ()
          |> retype
  
      //
      [<CompiledName("ToList")>]
      let inline toList (bimap : TagBimap<'Tag, 'T>) : (int<'Tag> * 'T) list =
          // Retype as IntBimap.
  