in src/ChildValidation/QuantifierConstraint.hack [18:31]
final public function legacySerialize(
): (LegacyExpressionType, mixed, mixed) {
$inner = $this->child;
$as_leaf = $inner->legacySerializeAsLeaf();
if ($as_leaf is nonnull) {
return tuple(static::LEGACY_EXPRESSION_TYPE, $as_leaf[0], $as_leaf[1]);
}
return tuple(
static::LEGACY_EXPRESSION_TYPE,
LegacyConstraintType::EXPRESSION,
$inner->legacySerialize(),
);
}