"One of array element" type

[javaDeveloperKid]

class A 
{
  /**
  * @var string[]
  */
  private const MY_CONST_ARRAY = ['foo', 'bar'];

  /**
   * @return ??? // e.g. one-of-value<self::MY_CONST_ARRAY>
   */
   function f(): string
   {
       return array_rand(self::MY_CONST_ARRAY);
   }
}

How can I tell PHPStan that my function will return one of a value from MY_CONST_ARRAY array?
The same question for array keys.

I know I can write type alias or just duplicate foo and bar strings but this is duplication. The array content is known so PHPStan could access it.

[javaDeveloperKid]

Got it.

class A 
{
  private const MY_CONST_ARRAY = ['foo', 'bar'];

  /**
   * @return value-of<self::MY_CONST_ARRAY>
   */
   function f(): string
   {
       return array_rand(self::MY_CONST_ARRAY);
   }
}