[Haskell] A puzzle and an annoying feature

[Lennart Augustsson]

Keean Schupke wrote:
> Daan Leijen wrote:
> 
>>
>> You are right, I feel like that too: one should expect that the type
>> checker can figure this out, and perhaps it is even really useful.
>> On the other hand, suppose you decide later to export the
>> class, and suddenly your code would no longer type check.
> 
> 
> I must have missed a mail... how could adding an export change the
> code?

If you export the class you can add another instance to it.  And now
my type variable would really be ambiguous.

	-- Lennart