We already have ::getReflectionConstant() and ::getReflectionConstants(), which return ReflectionClassConstant. Switching to doc bug.

Thanks, Nikita!

/**
 * @version php 7.1
 * @since 13-05-2017
 * @see http://php.net/manual/en/reflectionclass.getconstants.php
 */
class ReflClass
{
    //different constant visibility's types

    const PUBLIC_CONST = 'implicity public';
    public const PUBLIC_EXP = 'explicity public';
    protected const PROTECTED_CONST = 'protected';
    private const PRIVATE_CONST = 'private';
}

    // use of it
    $oClass = new ReflectionClass('ReflClass');

    foreach ($oClass->getConstants() as $const){

        var_dump($const);
    }
    
    /* this produce */
    // string(16) "implicity public"
    // string(16) "explicity public"
    // string(9) "protected"
    // string(7) "private"

I have the same problem, method is not documented.

PHP 7.1.2-4+deb.sury.org~yakkety+1 (cli) (built: Mar  2 2017 10:40:28) ( NTS )
Ubutnu 17.04