Clear Lsb Memoization

:::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. :::

Clear __MemoizeLSB data

• if $func is non-null, clear cache for $cls::$func
• if $func is null, clear all LSB memoization caches for $cls

namespace HH;

function clear_lsb_memoization(
  string $cls,
  ?string $func = NULL,
): bool;

Operates on a single class at a time. Clearing the cache for $cls::$func does not clear the cache for $otherClass::$func, for any other class.

Parameters

• string $cls
• ?string $func = NULL

Returns

• bool