"no value type specified in iterable type" for interface that extends IteratorAggregate with key and value types set explicitly via @extends

[ezzatron]

Bug report

When implementing a specific configuration of "nestable" iterable types, PHPStan will produce errors that claim "no value type specified in iterable type" for types that have been explicitly "un-genericised" using PHPDoc annotations.

This is a pretty strange use case that has been distilled from a more complex real-world case. The actual versions of the types represented here are:

• Collection is equivalent to EventCollection
• Member is equivalent to Call
• MemberImpl is equivalent to CallData
• CollectionImpl is equivalent to EventSequence

Code snippet that reproduces the problem

From https://phpstan.org/r/2594d7d7-d75e-4916-b924-f2120ab028c2:

<?php

/**
 * A collection that can contain members.
 *
 * @extends IteratorAggregate<int,Member>
 */
interface Collection extends IteratorAggregate
{
}

/**
 * A member of a collection. Also a collection containing only itself.
 *
 * In the real world, this would contain additional methods.
 */
interface Member extends Collection
{
}

class MemberImpl implements Member
{
    /**
     * @return Iterator<int,Member>
     */
    public function getIterator(): Iterator
    {
        return new ArrayIterator([$this]);
    }
}

class CollectionImpl implements Collection
{
    public function __construct(Member ...$members)
    {
        $this->members = $members;
    }

    /**
     * @return Member
     */
    public function getMember(): Member
    {
        return new MemberImpl();
    }

    /**
     * @return Iterator<int,Member>
     */
    public function getIterator(): Iterator
    {
        return new ArrayIterator($this->members);
    }

    /**
     * @var array<int,Member>
     */
    private $members;
}

Expected output

PHPStan should not produce an error. Instead it produces an error like:

Method CollectionImpl::getMember() return type has no value type specified in iterable type Member.

[ondrejmirtes]

Fixed, thank you! phpstan/phpstan-src@65e578c

[ezzatron]

Thank you for the fix!

[lock]

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.