anchor.diff:                          let handle = d.physicalDevices.[ii]
                           devices |> Array.find (fun dd -> dd.Handle = handle)
                       )
  -                PhysicalDeviceGroup(this, devices, extensions)
  +                PhysicalDeviceGroup(this, devices, extensions, apiVersion)
               )
               |> Array.filter (fun g -> g.Devices.Length > 1)
           else
  
positive.code: 
          )
  
  and PhysicalDevice internal(instance : Instance, handle : VkPhysicalDevice, enabledInstanceExtensions : list<string>) =
      static let allFormats = Enum.GetValues(typeof<VkFormat>) |> unbox<VkFormat[]>
  
      let availableLayers = 
  
negative.code:                 |> check "could not get physical devices"
          )
  
          devices |> Array.map (fun d -> PhysicalDevice(this, d, extensions, apiVersion))
  
      let groups =    
          if apiVersion >= Version(1,1) then
  