# `failure.outcome_success_missing`

Outcome match has no success arm.

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

```jadpo
function missing_success(key: LookupKey) -> LookupResult {
    return match lookup(key) {
        LookupMissing -> "missing"
        LookupRefused -> "refused"
    }
}
```

```text
error: This `match` doesn't handle `lookup(...)` succeeding
 --> main.jadpo:2:12
  |
2 |     return match lookup(key) {
  |            ^^^^^^^^^^^^^^^^^ no `success(...)` arm
  reason: A `match` on a call's outcome handles its value too, in a `success(name)` arm, as well as each failure.
  next: Add `success(value) -> ...` as the first arm (agent)
  rule: failure.outcome_success_missing
  help: https://jadpo.dev/docs/errors/failure.outcome_success_missing

check failed: 1 error, 2 files
```