InvalidCallbackArgumentException

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Exception thrown when an invalid argument is used as a callback

Interface Synopsis

final class InvalidCallbackArgumentException extends LogicException {...}