Is Final

:::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. :::

True iff the given type cannot be inherited

namespace HH\Facts;

function is_final(
  classname<mixed> $type,
): bool;

Parameters

• classname<mixed> $type

Returns

• bool