in src/ExpectObj.hack [97:115]
public function toBePHPEqualWithNANEqual(
mixed $expected,
string $msg = '',
mixed ...$args
): void {
$msg = \vsprintf($msg, $args);
$actual = $this->var;
if (
($expected is float) &&
($actual is float) &&
\is_nan($expected) &&
\is_nan($actual)
) {
return;
}
$this->toBePHPEqual($expected, '%s', $msg);
}