#2309: containers: specialize functions that fail in a Monad to Maybe

[Twan van Laarhoven]

apfelmus wrote:
> In any case, I prefer Maybe here as well because it's straightforward 
> and simple. Every other abstraction is just a  lift  away.

Following this line of reasoning: why is  1  syntactic sugar for  fromIntegral 
1? If 1 has type Integer then the generic value is just a fromIntergal away!

If we can make a function more convenient to use by making it more generic, I 
see no reason not to do so, as long as things remain safe.


Twan