RecastingRemovalRector.php

<?php

declare(strict_types=1);

namespace Rector\DeadCode\Rector\Cast;

use PhpParser\Node;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Cast;
use PhpParser\Node\Expr\Cast\Array_;
use PhpParser\Node\Expr\Cast\Bool_;
use PhpParser\Node\Expr\Cast\Double;
use PhpParser\Node\Expr\Cast\Int_;
use PhpParser\Node\Expr\Cast\Object_;
use PhpParser\Node\Expr\Cast\String_;
use PhpParser\Node\Expr\MethodCall;
use PhpParser\Node\Expr\StaticCall;
use PHPStan\Reflection\Php\PhpPropertyReflection;
use PHPStan\Type\ArrayType;
use PHPStan\Type\BooleanType;
use PHPStan\Type\Constant\ConstantArrayType;
use PHPStan\Type\FloatType;
use PHPStan\Type\IntegerType;
use PHPStan\Type\MixedType;
use PHPStan\Type\ObjectType;
use PHPStan\Type\StringType;
use PHPStan\Type\Type;
use PHPStan\Type\UnionType;
use Rector\NodeAnalyzer\ExprAnalyzer;
use Rector\NodeAnalyzer\PropertyFetchAnalyzer;
use Rector\Rector\AbstractRector;
use Rector\Reflection\ReflectionResolver;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;

/**
 * @see \Rector\Tests\DeadCode\Rector\Cast\RecastingRemovalRector\RecastingRemovalRectorTest
 */
final class RecastingRemovalRector extends AbstractRector
{
    /**
     * @var array<class-string<Node>, class-string<Type>>
     */
    private const CAST_CLASS_TO_NODE_TYPE = [
        String_::class => StringType::class,
        Bool_::class => BooleanType::class,
        Array_::class => ArrayType::class,
        Int_::class => IntegerType::class,
        Object_::class => ObjectType::class,
        Double::class => FloatType::class,
    ];

    public function __construct(
        private readonly PropertyFetchAnalyzer $propertyFetchAnalyzer,
        private readonly ReflectionResolver $reflectionResolver,
        private readonly ExprAnalyzer $exprAnalyzer,
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition('Remove recasting of the same type', [
            new CodeSample(
                <<<'CODE_SAMPLE'
$string = '';
$string = (string) $string;

$array = [];
$array = (array) $array;
CODE_SAMPLE
                ,
                <<<'CODE_SAMPLE'
$string = '';
$string = $string;

$array = [];
$array = $array;
CODE_SAMPLE
            ),
        ]);
    }

    /**
     * @return array<class-string<Node>>
     */
    public function getNodeTypes(): array
    {
        return [Cast::class];
    }

    /**
     * @param Cast $node
     */
    public function refactor(Node $node): ?Node
    {
        $nodeClass = $node::class;
        if (! isset(self::CAST_CLASS_TO_NODE_TYPE[$nodeClass])) {
            return null;
        }

        $nodeType = $this->nodeTypeResolver->getNativeType($node->expr);
        if ($nodeType instanceof MixedType) {
            return null;
        }

        if ($nodeType instanceof ConstantArrayType && $nodeClass === Array_::class) {
            if ($this->shouldSkip($node->expr)) {
                return null;
            }

            if ($this->shouldSkipCall($node->expr)) {
                return null;
            }

            return $node->expr;
        }

        $sameNodeType = self::CAST_CLASS_TO_NODE_TYPE[$nodeClass];
        if (! $nodeType instanceof $sameNodeType) {
            return null;
        }

        if ($this->shouldSkip($node->expr)) {
            return null;
        }

        if ($this->shouldSkipCall($node->expr)) {
            return null;
        }

        return $node->expr;
    }

    private function shouldSkipCall(Expr $expr): bool
    {
        if (! $expr instanceof MethodCall && ! $expr instanceof StaticCall) {
            return false;
        }

        $type = $this->nodeTypeResolver->getNativeType($expr);
        return $type instanceof MixedType && ! $type->isExplicitMixed();
    }

    private function shouldSkip(Expr $expr): bool
    {
        $type = $this->getType($expr);

        if ($type instanceof UnionType) {
            foreach ($type->getTypes() as $unionedType) {
                if ($unionedType instanceof MixedType) {
                    return true;
                }
            }
        }

        if (! $this->propertyFetchAnalyzer->isPropertyFetch($expr)) {
            return $this->exprAnalyzer->isNonTypedFromParam($expr);
        }

        $phpPropertyReflection = $this->reflectionResolver->resolvePropertyReflectionFromPropertyFetch($expr);
        if (! $phpPropertyReflection instanceof PhpPropertyReflection) {
            return true;
        }

        $nativeType = $phpPropertyReflection->getNativeType();
        return $nativeType instanceof MixedType;
    }
}