collector generics loose precision

[staabm]

Bug report

it seems the generic type of a collector is loosing precision..?

Code snippet that reproduces the problem

collector

/**
 * @implements Collector<CallLike, array{string, TaintType::TYPE_*, string, int}>
 */
final class SinkCollector implements Collector
{
    public function getNodeType(): string
    {
        return CallLike::class;
    }

    public function processNode(Node $node, Scope $scope)
    {}
}

/**
 * @psalm-immutable
 */
final class TaintType
{
    public const TYPE_INPUT = 'input';
    public const TYPE_SQL = 'sql';
    public const TYPE_HTML = 'html';

    public const TYPES = [self::TYPE_INPUT, self::TYPE_SQL, self::TYPE_HTML];
}

rule

/**
 * @implements Rule<CollectedDataNode>
 */
final class TaintRule implements Rule
{
    public function getNodeType(): string
    {
        return CollectedDataNode::class;
    }

    public function processNode(Node $node, Scope $scope): array
    {
        $sinkCollectorData = $node->get(SinkCollector::class);
        dumpType($sinkCollectorData);
       // actual: Dumped type: array<string, array<int, array{string, string, string, int}>> 
      // expected Dumped type: array<string, array<int, array{string, TaintType::TYPE_*,, string, int}>> 
    }
}

https://phpstan.org/r/72a1ea44-59e0-41c2-af31-11eeb6723b37

[mergeable]

This bug report is missing a link to reproduction at phpstan.org/try.

It will most likely be closed after manual review.

[ondrejmirtes]

Please reproduce it on the playground by replicating all the involved classes and interfaces.

[staabm]

just updated the description and added a link

[ondrejmirtes]

This is the infamous generics type generalization again.

[devnix]

Is there any known workaround to this issue?

[ondrejmirtes]

Last night I came up with the idea that we mostly shouldn't generalize the generic type variables, except when they're in object generics, like Foo<int>.

Here's the resulting PR: phpstan/phpstan-src#2818

We can't do this for objects, because I want new Collection([1, 2, 3]) to become Collection<int>. This could be improved in the future thanks to this suggestion: #6732 (comment) (but it's pretty complex to implement so for now it has to wait).

The new behaviour now only applies to bleeding edge (https://phpstan.org/blog/what-is-bleeding-edge) so definitely enable it to get the taste of the future 👍

[github-actions]

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