DowngradeVoidCastRector.php

<?php

declare(strict_types=1);

namespace Rector\DowngradePhp85\Rector\Expression;

use PhpParser\Node;
use PhpParser\Node\Expr\Assign;
use PhpParser\Node\Expr\Cast\Void_;
use PhpParser\Node\Expr\Variable;
use PhpParser\Node\Stmt\Expression;
use Rector\Naming\Naming\VariableNaming;
use Rector\PHPStan\ScopeFetcher;
use Rector\Rector\AbstractRector;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;

/**
 * @see https://wiki.php.net/rfc/marking_return_value_as_important
 * @see \Rector\Tests\DowngradePhp85\Rector\Expression\DowngradeVoidCastRector\DowngradeVoidCastRectorTest
 */
final class DowngradeVoidCastRector extends AbstractRector
{
    public function __construct(
        private readonly VariableNaming $variableNaming
    ) {
    }

    public function getNodeTypes(): array
    {
        return [Expression::class];
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition(
            'Replace void casts with proper handling of return values',
            [
                new CodeSample(
                    <<<'CODE_SAMPLE'
#[\NoDiscard]
function getPhpVersion(): string
{
    return 'PHP 8.5';
}

(void) getPhpVersion();
CODE_SAMPLE
                    ,
                    <<<'CODE_SAMPLE'
#[\NoDiscard]
function getPhpVersion(): string
{
    return 'PHP 8.5';
}

$_void = getPhpVersion();
CODE_SAMPLE
                ),
            ]
        );
    }

    /**
     * @param Expression $node
     */
    public function refactor(Node $node): ?Node
    {
        if (! $node->expr instanceof Void_) {
            return null;
        }

        $scope = ScopeFetcher::fetch($node);
        $variable = new Variable($this->variableNaming->createCountedValueName('_void', $scope));

        // the assign is needed to avoid warning
        // see https://3v4l.org/ie68D#v8.5.3 vs https://3v4l.org/nLc5J#v8.5.3
        $node->expr = new Assign(
            $variable,
            $node->expr->expr
        );
        return $node;
    }
}