1// compile
2
3// Copyright 2018 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7// Triggers a bug in writebarrier, which inserts one
8// between (first block) OpAddr x and (second block) a VarDef x,
9// which are then in the wrong order and unable to be
10// properly scheduled.
11
12package q
13
14var S interface{}
15
16func F(n int) {
17	fun := func(x int) int {
18		S = 1
19		return n
20	}
21	i := fun(([]int{})[n])
22
23	var fc [2]chan int
24	S = (([1][2]chan int{fc})[i][i])
25}
26