Removing bitSize

[Henning Thielemann]

On Mon, 10 Jul 2017, David Feuer wrote:

> The long-deprecated bitSize method of the Bits class is slated to be
> removed in base-4.11 (GHC 8.4). There is one remaining question:
> should we replace it with a *function* by that name with a FiniteBits
> constraint? I don't feel very strongly either way, but Ryan Scott
> seems in favor and Edward Kmett seems opposed. So it seems best to
> bring it to the libraries list and let the CLC make the call. If the
> function is added, it would look like this:
>
> bitSize :: FiniteBits a => a -> Int
> bitSize = finiteBitSize

I'd like to have a solution that allows me to make my code compilable by 
many GHC versions. The top-level function with an almost identical 
signature seems to fit that requirement best. The solutions using Proxy, 
Tagged, and TypeApplication are nice, too, but since there are many 
sensible choices there might also be many functions like bitSizeProxy, 
bitSizeTagged, bitSizeTypeApp.