Statements: Return

A return statement can only occur inside a function, in which case, it causes that function to terminate normally. The function can optionally return a single value (but one which could contain other values, as in a tuple, a shape, or an object of some user-defined type), whose type must be compatible with the function's declared return type. If the return statement contains no value, or there is no return statement (in which case, execution drops into the function's closing brace), no value is returned. For example:

<?hh // strict

namespace Hack\UserDocumentation\Statements\Return\Examples\Various;

function average_float(float $p1, float $p2): float {
  return ($p1 + $p2) / 2.0;
}

type IdSet = shape('id' => ?string, 'url' => ?string, 'count' => int);
function get_IdSet(): IdSet {
  return shape('id' => null, 'url' => null, 'count' => 0);
}

class Point {
  private float $x;
  private float $y;
  public function __construct(num $x = 0, num $y = 0) {
    $this->x = (float)$x; // sets private property $x
    $this->y = (float)$y; // sets private property $y
  } // no return statement
  public function move(num $x = 0, num $y = 0): void {
    $this->x = (float)$x; // sets private property $x
    $this->y = (float)$y; // sets private property $y
    return; // return nothing
  }
  // ...
}

However, for an async function having a void return type, an object of type Awaitable<void> is returned. For an async function, the value having a non-void return type, the return value is wrapped in an object of type Awaitable<T> (where T is the type of the return value), which is returned.

Returning from a constructor behaves just like returning from a function having a return type of void.

The value returned by a generator function must be the literal null. A return statement inside a generator function causes the generator to terminate.

A return statement must not occur in a finally block or in a function declared noreturn.