> */ private const SIDE_EFFECT_NODE_TYPES = [\PhpParser\Node\Scalar\Encapsed::class, \PhpParser\Node\Expr\New_::class, \PhpParser\Node\Expr\BinaryOp\Concat::class, \PhpParser\Node\Expr\PropertyFetch::class]; /** * @var \Rector\NodeTypeResolver\NodeTypeResolver */ private $nodeTypeResolver; /** * @var \Rector\DeadCode\SideEffect\PureFunctionDetector */ private $pureFunctionDetector; public function __construct(\Rector\NodeTypeResolver\NodeTypeResolver $nodeTypeResolver, \Rector\DeadCode\SideEffect\PureFunctionDetector $pureFunctionDetector) { $this->nodeTypeResolver = $nodeTypeResolver; $this->pureFunctionDetector = $pureFunctionDetector; } public function detect(\PhpParser\Node\Expr $expr) : bool { if ($expr instanceof \PhpParser\Node\Expr\Assign) { return \true; } $exprStaticType = $this->nodeTypeResolver->resolve($expr); if ($exprStaticType instanceof \PHPStan\Type\ConstantType) { return \false; } foreach (self::SIDE_EFFECT_NODE_TYPES as $sideEffectNodeType) { if (\is_a($expr, $sideEffectNodeType, \true)) { return \false; } } if ($expr instanceof \PhpParser\Node\Expr\FuncCall) { return !$this->pureFunctionDetector->detect($expr); } if ($expr instanceof \PhpParser\Node\Expr\Variable || $expr instanceof \PhpParser\Node\Expr\ArrayDimFetch) { $variable = $this->resolveVariable($expr); // variables don't have side effects return !$variable instanceof \PhpParser\Node\Expr\Variable; } return \true; } private function resolveVariable(\PhpParser\Node\Expr $expr) : ?\PhpParser\Node\Expr\Variable { while ($expr instanceof \PhpParser\Node\Expr\ArrayDimFetch) { $expr = $expr->var; } if (!$expr instanceof \PhpParser\Node\Expr\Variable) { return null; } return $expr; } }