sr15823-second-reproducer.swift

import _Differentiation

func myFunc(x: Float, y: Float) -> Float { x + y }

let item: @differentiable(reverse) (Float, Float) -> Float = myFunc

class Box<T> {
  var value: T
  init(value: T) {
    self.value = value
  }
}

let box = Box(value: item)
let retrieved = box.value

Linked to: https://gist.github.com/philipturner/260d44f889c58f83bc3c3d7d830cbe1b