# MagentoGroupedProductModelProductTypeGrouped

public function getAssociatedProducts($product)
{
    if (!$product->hasData($this->_keyAssociatedProducts)) {
        $associatedProducts = [];

        $this->setSaleableStatus($product);

        $collection = $this->getAssociatedProductCollection(
            $product
        )->addAttributeToSelect(
            ['name', 'price',  'special_price', 'special_from_date', 'special_to_date']
        )->addFilterByRequiredOptions()->setPositionOrder()->addStoreFilter(
            $this->getStoreFilter($product)
        )->addAttributeToFilter(
            'status',
            ['in' => $this->getStatusFilters($product)]
        );

        foreach ($collection as $item) {
            $associatedProducts[] = $item;
        }

        $product->setData($this->_keyAssociatedProducts, $associatedProducts);
    }
    return $product->getData($this->_keyAssociatedProducts);
}

Uncaught TypeError: Argument 1 passed to Vendor\Swatches\Plugin\GroupedSwatches::afterGetAssociatedProducts() must be an instance of Magento\Catalog\Model\Product, instance of Magento\GroupedProduct\Model\Product\Type\Grouped\Interceptor given

public function afterGetAssociatedProducts(MagentoCatalogModelProduct $product, $result)
{
    $associatedProducts = array();
    $collection = $product->getAssociatedProductCollection(
        $product
    )->addAttributeToSelect(
        ['name', 'price', 'special_price', 'special_from_date', 'special_to_date', 'image', 'small_image', 'thumbnail']
    )->addFilterByRequiredOptions()->setPositionOrder()->addStoreFilter(
        $this->getStoreFilter($product)
    )->addAttributeToFilter(
        'status',
        ['in' => $this->getStatusFilters($product)]
    );

    foreach ($collection as $item) {
        $associatedProducts[] = $item;
    }

    $product->setData($this->_keyAssociatedProducts, $associatedProducts);

    return $result;
}