Generic function returns generic Closure

[SyuTingSong]

Feature request

I create a function that returns a closure.

/**
 * @template TKey of array-key
 * @template RKey of array-key
 * @template TValue
 *
 * @param callable(TKey):RKey $fn
 *
 * @return Closure(iterable<TKey,TValue>):Generator<RKey,TValue>
 */
function map_keys(callable $fn): Closure
{
    return function(iterable $iterable) use ($fn): Generator {
        foreach($iterable as $key => $value) {
            $mapped_key = $fn($key);
            yield $mapped_key => $value;
        }
    };
}

Currently, the PHPStan reports an error:

Template type TValue of function map_keys() is not referenced in a parameter.

Open in playground.

I hope I can declare the TValue as a template of the returning closure, instead a template of the function map_keys.

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No response

[ondrejmirtes]

Duplicate of #8964

[github-actions]

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