# 恐慌：从已关闭的通道接收（在range中）

- **ID:** `go/goroutine-range-over-closed-channel`
- **领域:** go
- **类别:** runtime_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

在通道关闭后使用range迭代；range会接收零值直到通道耗尽。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 1.0 | active | — | — |
| 1.20 | active | — | — |

## 解决方案

1. **Use for with ok pattern instead of range** (95% 成功率)
   ```
   for {
    val, ok := <-ch
    if !ok {
        break
    }
    // process val
}
   ```
2. **Ensure channel is closed only after all sends are done** (90% 成功率)
   ```
   var wg sync.WaitGroup
for i := 0; i < 5; i++ {
    wg.Add(1)
    go func() {
        defer wg.Done()
        ch <- i
    }()
}
wg.Wait()
close(ch)
for val := range ch {
    // process
}
   ```

## 无效尝试

- **Using recover() to catch panic from zero value** — Range over closed channel doesn't panic; it returns zero values, which may cause logic errors. (90% 失败率)
- **Checking channel length before range** — len(ch) doesn't indicate closed state; closed channel can have buffered data. (80% 失败率)