Eloquent update with DB::raw triggers Object of class Illuminate/Database/Query/Expression could not be converted to int

[LiXunGuan]

related question:#28196

Define casts in inventoryBatch model

    protected $casts = [
        'number' => 'integer',
        'price'  => 'integer'
    ];

Project code

$detail->inventoryBatch->update(
    'amount' => DB::raw('amount + 1'),
    'number' => DB::raw('number + 5')
)

I got this notice going:

ErrorException: Object of class Illuminate\Database\Query\Expression could not be converted to int in D:\wwwroot\his\app\Models\InventoryBatchs.php:35

I tried to comment out $casts, the definition of getAmountAttribute and getPriceAttribute still reported the same error