| // Copyright 2021 The Go Authors. All rights reserved. | |
| // Use of this source code is governed by a BSD-style | |
| // license that can be found in the LICENSE file. | |
| package main | |
| type Box[A any] struct { | |
| value A | |
| } | |
| func Nest[A /* ERROR "instantiation cycle" */ any](b Box[A], n int) interface{} { | |
| if n == 0 { | |
| return b | |
| } | |
| return Nest(Box[Box[A]]{b}, n-1) | |
| } | |
| func main() { | |
| Nest(Box[int]{0}, 10) | |
| } |