src/PhpToZephir/Converter/Manipulator/ArrayManipulator.php
private function isInvalidInArrayDimFetch($node)
    {
        if (property_exists($node, 'dim') === false) {
            return $this->isInvalidIn($node);
        } elseif ($node->dim instanceof BinaryOp\Concat) {
            return $this->isInvalidInArrayDimFetch($node->dim->left)
            && $this->isInvalidInArrayDimFetch($node->dim->right);
        } else {
            return $this->isInvalidIn($node->dim);
        }
    }
private function isInvalidInArrayDimFetch($node)
    {
        if (property_exists($node, 'dim') === false) {
            return $this->isInvalidIn($node);
        } elseif ($node->dim instanceof BinaryOp\Concat) {
            return $this->isInvalidInArrayDimFetch($node->dim->left)
            && $this->isInvalidInArrayDimFetch($node->dim->right);
        } else {
            return $this->isInvalidIn($node->dim);
        }
    }
@param unknown $node

@return bool