class.hh

<?hh

class Example {
  private int $numberNine = 9;
}

dd.hh

<?hh

const int NUMBER_NINE = 9;

function.hh

<?hh

function example(TypeOne $typeOne, int $anInteger){}

generics.hh

<?hh

namespace Examples;

class Value<T>
{
  public function __construct(private T $value) {}

  public function get(): T {
    return $this->value;
  }
}

class Constraint
{
    public function isEqual<T>(T $valueOne, T $valueTwo) {
      return ($valueOne == $valueTwo);
    }
}

return.hh

<?hh

function returnsTrue(): bool { return true; }