Support for nullsafe function call syntax

Description

The following code:

<?php
class Foo {
    public function __invoke(): string {
        return 'foo invoked';
    }
}

$f = new Foo();
var_Dump($f());

results in this expected output:

string(11) "foo invoked"

$g = null;
$g();

results in this expected output

Fatal error: Uncaught Error: Value of type null is not callable

$g = null;
$g?->__invoke();

results in this expected output:

string(11) "foo invoked"

As the call to ->__invoke() can be shortened to () I would have expected to be able to use the nullsafe operator here as well and write

$g = null;
$g?();

But this results in in this output:

Parse error: syntax error, unexpected token ")"

I would have expected

string(11) "foo invoked"

Is this on purpose? I could not find any mention of invoke in the RFC. So was this overseen?

See also https://3v4l.org/n09i2

PHP Version

All currently supported PHP-Versions

Operating System

No response

使用 issue 中的 PHP 代码片段重现所报告的行为，然后阅读链接的 nullsafe operator RFC，以及现有的 nullsafe 调用实现和测试。完成的标准是确定并实现对 $g?() 的预期处理，同时保留普通调用的已记录错误，并符合预期行为。