anchor.diff:                          let body = &bodies.[i]
                           body.LinearVelocity <- body.LinearVelocity + gravity
                           i <- inc i
  -                    (Output.empty, bodies)
  +                    Output.empty
                   | Attractor (position, radius, force) ->
                       let mutable i = 0
                       while i < dec bodies.Length do
  
positive.code: 
      /// Transforms a constrained value.
      type 'a Transformer =
          int64 -> Constraint -> 'a SegmentedArray -> (Output * 'a SegmentedArray)
  
      [<RequireQualifiedAccess>]
      module Transformer =
  
negative.code:     [<RequireQualifiedAccess>]
      module Scope =
  
          /// Make a scope with in-place in and out delegates.
          let inline make<'a, 'b when 'a : struct> (getField : In<'a, 'b>) (setField : Out<'a, 'b>) : Scope<'a, 'b> =
              { In =
                  fun (targets : 'a SegmentedArray) ->
                      let fields = SegmentedArray.zeroCreate targets.Length
  