Generic of Traverable

ging-dev

<?php

class Result implements IteratorAggregate {
    public function getIterator() {
        return new ArrayIterator($this);
    }
}

/** @var Result<int> */
$a = new Result();

foreach ($a as $item) {
	\PHPStan\dumpType($item);
}

phpstan understands $item as int, but LSP return Tvalue.

JakubMisek

ging-dev thank you! You are right, although the code is not exactly according to PHPStan specifications (which we follow). There should be a @template annotation:

/**
  * @template TValue
  * @implements IteratorAggregate<int, TValue>
  */
class Result ...

Anyways; we'll try to implement the functionality even without the @template specified.

JakubMisek

ging-dev Currently, the first case needs two generic arguments, then it works. i.e.:

/** @var Result<mixed, int> */
$a = new Result();

foreach ($a as $item) ...

We'll update the code analysis, to handle the case with one generic argument only.

The second case with iterable has been fixed; the fix will be in the next update.

ging-dev

<?php

/** @var iterable<int,string> */
$a = [];
foreach ($a as $item) {
	// $item is string, but LSP return int|string
}

JakubMisek

ging-dev you are right, it's just not according to PHPStan specification (https://phpstan.org/writing-php-code/phpdoc-types#iterables) so we don't handle that case now.

We'll implement this behavior in a future update.

ging-dev

JakubMisek yes, also /** @var Result&\IteratorAggregate<int,string> */ doesn't seem to work either

JakubMisek

ging-dev just noting, @var supposes to only work above variables.

ging-dev

JakubMisek yes

<?php

interface Test
{
    public function some(): string;
}

class Result {
}

/** @var Result&\IteratorAggregate<Test> */
$a = new Result();

foreach ($a as $item) {
// $item should be Test in this case
}

JakubMisek

ging-dev let me try, that should work

JakubMisek

ging-dev I see, it gets confused by Result (which we don't annotate correctly yet) and results in mixed

The following is a quick workaround before we fix it.

/** @var \IteratorAggregate<Test> */