This API is part of the Hack Standard Library, not HHVM itself.
Facebook Engineer?

This function is available as Keyset\equal() in Facebook's www repository.

Returns whether the two given keysets have the same elements, using strict equality


namespace HH\Lib\Keyset;

function equal<Tv as arraykey>(
  keyset<Tv> $keyset1,
  keyset<Tv> $keyset2,
): bool;

To guarantee equality of order as well as contents, use ===.


  • keyset<Tv> $keyset1
  • keyset<Tv> $keyset2