[Haskell-cafe] RE: Typing problems with basic arithmetic - help!

[Scherrer, Chad]

> For some reason the following code is producing an error 
> message from ghci that the the patterns are non-exhaustive. 
> Does anyone have any idea why that could be, given that the 
> patterns are, at least in my meaning, provably exhaustive?
> 

You forgot to match against the empty list. Try adding 
choosenonuniqueset n [] = []

-Chad Scherrer