Can't instantiate generic object with type restriction

[alexeypetrushin]

Code below won't work, but if type restriction `J: Job` removed and just the 
`J` used it works. How to fix that?
    
    
    type
      Job = object of RootObj
        id: string
      
      Container[J: Job] = object
        job: J
      
      GetPriceJob = object of Job
        message: string
    
    discard Container[GetPriceJob]()
    
    
    Run