Integer ranges not checked correctly

[sebastianbergmann]

I have a method Position::fromFileAndRank() that uses @psalm-param int<1,8> annotations to limit the range of integer parameters to values >= 1 && <= 8:

final class Position
{
    /**
     * @psalm-param int<1,8> $file
     * @psalm-param int<1,8> $rank
     */
    public static function fromFileAndRank(int $file, int $rank): self
    {
        return new self($file, $rank);
    }
}

I have code that calls the method shown above after ensuring that the arguments to be passed are within the range the parameters expect:

$file = $this->position()->file() + $offset['file'];
$rank = $this->position()->rank() + $offset['rank'];

if ($file >= 1 && $file <= 8 && $rank >= 1 && $rank <= 8) {
    $positions[] = Position::fromFileAndRank($file, $rank);
}

But Psalm claims that the arguments are not within the range the parameters expect:

ERROR: [InvalidArgument] ... Argument 1 of Position::fromFileAndRank expects int<1, 8>, but int<min, max> provided

ERROR: [InvalidArgument] ... Argument 2 of Position::fromFileAndRank expects int<1, 8>, but int<min, max> provided

Reproducing example: https://psalm.dev/r/75a668a862

From the documentation of integer ranges it is not clear to me whether Psalm only allows literal integers or whether it should be able to infer that a variable is within range.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/75a668a862

<?php declare(strict_types=1);
abstract class Piece
{
    private readonly Position $position;

    private function __construct(Position $position)
    {
        $this->position = $position;
    }

    /**
     * @psalm-mutation-free
     */
    public function position(): Position
    {
        return $this->position;
    }

    /**
     * @psalm-param list<array{file: int, rank: int}> $offsets
     */
    protected function offsetsToTargetPositionCandidates(array $offsets): void
    {
        $positions = [];

        foreach ($offsets as $offset) {
            $file = $this->position()->file() + $offset['file'];
            $rank = $this->position()->rank() + $offset['rank'];

            if ($file >= 1 && $file <= 8 && $rank >= 1 && $rank <= 8) {
                $positions[] = Position::fromFileAndRank($file, $rank);
            }
        }
    }
}

/**
 * @psalm-immutable
 */
final class Position
{
    /**
     * @psalm-var int<1,8>
     */
    private readonly int $file;

    /**
     * @psalm-var int<1,8>
     */
    private readonly int $rank;

    /**
     * @psalm-param int<1,8> $file
     * @psalm-param int<1,8> $rank
     */
    public static function fromFileAndRank(int $file, int $rank): self
    {
        return new self($file, $rank);
    }

    /**
     * @psalm-param int<1,8> $file
     * @psalm-param int<1,8> $rank
     */
    private function __construct(int $file, int $rank)
    {
        $this->file = $file;
        $this->rank = $rank;
    }

    /**
     * @psalm-return int<1,8>
     */
    public function file(): int
    {
        return $this->file;
    }

    /**
     * @psalm-return int<1,8>
     */
    public function rank(): int
    {
        return $this->rank;
    }
}

Psalm output (using commit d2f7d86):

ERROR: InvalidArgument - 31:58 - Argument 1 of Position::fromFileAndRank expects int<1, 8>, but int<min, max> provided

ERROR: InvalidArgument - 31:65 - Argument 2 of Position::fromFileAndRank expects int<1, 8>, but int<min, max> provided

INFO: UnusedVariable - 24:9 - $positions is never referenced or the value is not used

[still-dreaming-1]

Interestingly, this workaround avoids the issue somehow. Psalm is apparently able to infer the correct types of the ints after comparisons in this case: https://psalm.dev/r/9251fdd044

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/9251fdd044

<?php declare(strict_types=1);
abstract class Piece
{
    private readonly Position $position;

    private function __construct(Position $position)
    {
        $this->position = $position;
    }

    /**
     * @psalm-mutation-free
     */
    public function position(): Position
    {
        return $this->position;
    }

    /**
     * @psalm-param list<array{file: int, rank: int}> $offsets
     */
    protected function offsetsToTargetPositionCandidates(array $offsets): void
    {
        $positions = [];

        foreach ($offsets as $offset) {
            $file = $this->position()->file() + $offset['file'];
            $rank = $this->position()->rank() + $offset['rank'];

            $position = Position::fromFileAndRankIfWithinRange($file, $rank);
            if ($position !== null) {
                $positions[] = $position;
            }
        }
    }
}

/**
 * @psalm-immutable
 */
final class Position
{
    /**
     * @psalm-var int<1,8>
     */
    private readonly int $file;

    /**
     * @psalm-var int<1,8>
     */
    private readonly int $rank;

    /**
     * @psalm-param int<1,8> $file
     * @psalm-param int<1,8> $rank
     */
    public static function fromFileAndRank(int $file, int $rank): self
    {
        return new self($file, $rank);
    }
    
    /**
     * @psalm-param int $file
     * @psalm-param int $rank
     */
    public static function fromFileAndRankIfWithinRange(int $file, int $rank): ?self
    {
        if ($file >= 1 && $file <= 8 && $rank >= 1 && $rank <= 8) {
        	return self::fromFileAndRank($file, $rank);
        }
        return null;
    }

    /**
     * @psalm-param int<1,8> $file
     * @psalm-param int<1,8> $rank
     */
    private function __construct(int $file, int $rank)
    {
        $this->file = $file;
        $this->rank = $rank;
    }

    /**
     * @psalm-return int<1,8>
     */
    public function file(): int
    {
        return $this->file;
    }

    /**
     * @psalm-return int<1,8>
     */
    public function rank(): int
    {
        return $this->rank;
    }
}

Psalm output (using commit 16cdeb9):

INFO: UnusedVariable - 24:9 - $positions is never referenced or the value is not used

[theodorejb]

@orklah It looks like this was also fixed by #8934.