# ErrorReason
<span class="source-link">[[Source]](src/options/options.md#L85)</span>
```pony
type ErrorReason is
  (UnrecognisedOption val | MissingArgument val | InvalidArgument val | AmbiguousMatch val)
```

#### Type Alias For

* ([UnrecognisedOption](options-UnrecognisedOption) val | [MissingArgument](options-MissingArgument) val | [InvalidArgument](options-InvalidArgument) val | [AmbiguousMatch](options-AmbiguousMatch) val)

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