Fatal error: Cannot use result of built-in function in write context

[mvorisek]

Description

The following code:

repro: https://3v4l.org/E8CsC

<?php

class Cl {
    public static function createAnd(...$args)
    {
        var_dump($args);
    }
    
    public function bar()
    {
        static::createAnd(func_get_args()[0]);
    }
}

(new Cl())->bar('y');

Resulted in this output:

Fatal error: Cannot use result of built-in function in write context

But I expected this output instead:

array(1) {
  [0]=>
  string(1) "y"
}

the 3v4l repro shows the issue is present only in some cases, when the same code is in non-class AST, it works

(func_get_args()[0] should return the 1st argument, it is simplified repro from more complex usecase)

PHP Version

any

Operating System

any

[mvorisek]

it seems:

createAnd(func_get_args()[0]);

compiles, but:

static::createAnd(func_get_args()[0]);

and

$this->createAnd(func_get_args()[0]);

does not

[KapitanOczywisty]

self::createAnd(func_get_args()[0]); also works. Possibly it's assuming that extending class could have reference there, though i don't think this is technically possible with variadic method.

[mvorisek]

Even with static:: and final class/method :)

Seems like a parser limitation.