Missing 'case' statements for 'iota' consts in 'switch'

Reports unhandled values in switch statements when the iota identifier is in the const declaration. To handle these values, consider using case or default clauses.

The iota keyword in Go creates a sequence of integers in a const block. Although the Go compiler does not require handling all iota values, missing some of them could indicate a bug.

For more information about iota, refer to Iota at go.dev.

Examples:

const (
  a = iota
  b
  c = -5
)

func main() {
  v := 5
  switch v {
  case a:
    break;
  case b:
    break;
  }
}

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.

GoSwitchMissingCasesForIotaConsts

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

The IDE triggers an inspection because c is not handled by the switch statement. Note that c is in the same const block even if it does not use iota.

Quick-fix options are Create 'case' clause for values and Create 'default' clause. After the Create 'default' clause quick-fix is applied:

const (
  a = iota
  b
  c
)

func main() {
  v := 5
  switch v {
  case a:
    break;
  default:
  }
}

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