| // run | |
| // 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 | |
| import "runtime" | |
| type T [4]int // N.B., [4]int avoids runtime's tiny object allocator | |
| //go:noinline | |
| func g(x []*T) ([]*T, []*T) { return x, x } | |
| func main() { | |
| const Jenny = 8675309 | |
| s := [10]*T{{Jenny}} | |
| done := make(chan struct{}) | |
| runtime.SetFinalizer(s[0], func(p *T) { close(done) }) | |
| var h, _ interface{} = g(s[:]) | |
| if wait(done) { | |
| panic("GC'd early") | |
| } | |
| if h.([]*T)[0][0] != Jenny { | |
| panic("lost Jenny's number") | |
| } | |
| if !wait(done) { | |
| panic("never GC'd") | |
| } | |
| } | |
| func wait(done <-chan struct{}) bool { | |
| for i := 0; i < 10; i++ { | |
| runtime.GC() | |
| select { | |
| case <-done: | |
| return true | |
| default: | |
| } | |
| } | |
| return false | |
| } |