Loop variables captured by the func literal

Reports references to loop variables from within func literals in defer and go statements. Such variables might have unexpected values because they are not copied to func literals, and the func literals in defer and go are not executed immediately.

For more information about closures and goroutines, refer to What happens with closures running as goroutines? at go.dev.

Example:

for _, v := range []string{"a", "b", "c"} {
  go func() {
    fmt.Println(v) // output will likely be `c c c`, not `a b c`
  }()
}

After the quick-fix is applied:

for _, v := range []string{"a", "b", "c"} {
  v := v // `v` is copied now
  go func() {
    fmt.Println(v)
  }()
}

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

GoLoopClosure

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Go | Probable bugs

Note the analyzer only checks defer and go statements when they are the last statement in the loop body. Otherwise, the analysis might produce false detections.

Availability

By default bundled with: GoLand 2024.1, Qodana for Go 2024.1,
Can be installed with plugin: Go, 241.SNAPSHOT

Last modified: 18 June 2024