Well direct casting is unsafe and is to be avoided especially for generics. If
the program flow allows it's best to just write.
var myVideo = TVideo()
var myVideoList = @[TMedia myVideo] # No need to cast when it's not a video
list
setNewDims(myVideoList)
Run
The best way to write the generic solution is
proc setNewDims[T: Media](arr:seq[T])=
echo arr[0].id
Run
Nim's generics over inheritance are invariant, this means that just cause two
generic parameters are interchangeable the overall type instance is not. It is
not a simple problem given you can have the following typedef:
type MyType[T] = object
when T is Video:
someVal: int
else:
someOtherVal: float
Run
