# `failure.outcome_wildcard`

Outcome match uses a wildcard.

Area 3, [Logic](../topics/logic.md); not declinable; the next step is usually the agent's.

```jadpo
function wildcard_failure(key: LookupKey) -> LookupResult {
    return match lookup(key) {
        success(value) -> value
        _ -> "fallback"
    }
}
```

```text
error: `_` can't stand for a call's failures
 --> main.jadpo:4:9
  |
4 |         _ -> "fallback"
  |         ^ wildcard
  reason: Every failure a call can give has an arm of its own, so a failure added to the call later is caught at every `match` that has to consider it.
  next: Replace `_` with arms for `LookupMissing` and `LookupRefused` (agent)
  rule: failure.outcome_wildcard
  help: https://jadpo.dev/docs/errors/failure.outcome_wildcard

check failed: 1 error, 2 files
```