in src/CodegenTrait.hack [46:59]
private function buildRequires(HackBuilder $builder): void {
if (
C\is_empty($this->requireClass) && C\is_empty($this->requireInterface)
) {
return;
}
$builder->ensureEmptyLine();
foreach ($this->requireClass as $class) {
$builder->addLinef('require extends %s;', $class);
}
foreach ($this->requireInterface as $interface) {
$builder->addLinef('require implements %s;', $interface);
}
}