Unknown type within template with @param array<T>

[sanmai]

https://psalm.dev/r/508b2bc5aa

/**
 * @template T
 */
interface ItemList
{
    /**
     * @param array<T> $list
     * @return static<T>
     */
    public static function withList(array $list);
}

ERROR: UndefinedDocblockClass - 10:15 - Docblock-defined class or interface T does not exist

All the while other uses of T are not reported. It's either this one use in @param is not an error, or other uses must be errors too.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/508b2bc5aa

<?php
/**
 * @template T
 */
interface ItemList
{
    /**
     * @param array<T> $list
     * @return static<T>
     */
    public static function withList(array $list);
}

Psalm output (using commit 19f88a2):

ERROR: UndefinedDocblockClass - 8:15 - Docblock-defined class or interface T does not exist

[jost125]

From what I was googling, it looks, that psalm does not inherit template T for static methods. There is more (closed) issues like that.

The solution here is to "repeat" template here, like this:

/**
 * @template T
 */
interface ItemList
{
    /**
     * @template T2
     * @param array<T2> $list
     * @return static<T2>
     */
    public static function withList(array $list);
}

But I have another problem with this. Phpstan and psalm are imcompatible with this. Phpstan inherits it.

You can write it this way in phpsan as well, but it behaves diferently.

Result is, that you cannot use both phpstan and psalm in single project with generics used in static functions.

Here is releated issue in phpstan (about incompability) by @muglug
phpstan/phpstan#2738

Here is example of releated (closed) issue in psalm
#2751

It would be great, if both tools would have same behavior for this.

[thunderer]

@jost125 from what I understand @muglug reenabled templates inheritance on static methods in #2751, was it disabled somewhere between February and now as in that linked PHPStan issue? I'm trying to get thunderer/Platenum#24 to work with Psalm templates so that you can restrict the available values on the type level. Enumerations in PHP are implemented through Multiton, so the classes rely on static methods a lot. I would like to "specify" template values in the outermost classes (T of self::*) which would then propagate back to the EnumTrait.

How does your example above work? Is it possible to link these templates like @psalm-template T2 of T?