Exclude class-string and string from normalization with Union type

[zonuexe]

Feature request

I've tried extending PSR-11 with a stub to create a conditional return type that returns an instance of a class name.

<?php

declare(strict_types=1);

namespace Psr\Container;

/**
 * Describes the interface of a container that exposes methods to read its entries.
 */
interface ContainerInterface
{
    /**
     * @template T
     * @phpstan-param string|class-string<T> $id
     * @phpstan-return ($id is class-string<T> ? T : mixed)
     */
    public function get(string $id);

    /**
     * @param string $id Identifier of the entry to look for.
     * @return bool
     */
    public function has(string $id);
}

https://phpstan.org/r/0cf57a6a-db47-46fa-838b-0128a1beef6d

Contrary to expectations, this conditional return type does not work because string|class-string<T> is normalized to string.
string is a super type of class-string, but in practice I think it is more convenient to keep it as a union type without normalizing it.

Did PHPStan help you today? Did it make you happy in any way?

We've written some PHPStan extensions for our internal projects, but we're very pleased with the introduction of the conditional return type as we can't keep up with the implementation of the extensions to meet the demand ❤️

[rvanvelzen]

Duplicate of #7141

[ondrejmirtes]

Please read and follow the original issue.

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.