| // run |
| |
| // Copyright 2020 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 |
| |
| var ch chan int |
| var x int |
| |
| func f() int { |
| close(ch) |
| ch = nil |
| return 0 |
| } |
| |
| func g() int { |
| ch = nil |
| x = 0 |
| return 0 |
| } |
| |
| func main() { |
| var nilch chan int |
| var v int |
| var ok bool |
| _, _ = v, ok |
| |
| ch = make(chan int) |
| select { |
| case <-ch: |
| case nilch <- f(): |
| } |
| |
| ch = make(chan int) |
| select { |
| case v = <-ch: |
| case nilch <- f(): |
| } |
| |
| ch = make(chan int) |
| select { |
| case v := <-ch: _ = v |
| case nilch <- f(): |
| } |
| |
| ch = make(chan int) |
| select { |
| case v, ok = <-ch: |
| case nilch <- f(): |
| } |
| |
| ch = make(chan int) |
| select { |
| case v, ok := <-ch: _, _ = v, ok |
| case nilch <- f(): |
| } |
| |
| ch1 := make(chan int, 1) |
| ch = ch1 |
| x = 42 |
| select { |
| case ch <- x: |
| case nilch <- g(): |
| } |
| if got := <-ch1; got != 42 { |
| panic(got) |
| } |
| } |