Skip to main content

immutable

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.

Returns an immutable version of this collection

public function immutable(): this;

Because a Pair is immutable by default, this just returns the current object.

Returns​