Can't use attributes with interface constants and methods

<?php

#[I1]
interface I {
    #[I2(1)] // syntax error occurs
    public const I_CONST = "interface";
    #[I3] // syntax error occurs
    public function method(#[I4] $param1, #[I5(), I6("test")] $param): void; // syntax error occurs
}
$refI = new \ReflectionClass(I::class);
$sourcesI = [
    $refI,
    $refI->getReflectionConstant('I_CONST'),
    $refI->getMethod('method'),
    $refI->getMethod('method')->getParameters()[0],
    $refI->getMethod('method')->getParameters()[1],
];

foreach ($sourcesI as $r) {
	$attr = $r->getAttributes();
	var_dump(get_class($r), count($attr));

    foreach ($attr as $a) {
        var_dump($a->getName(), $a->getArguments());
    }

    echo "\n";
}