Re: Monads, Functors and typeclasses

[Philip Wadler]

> Maybe we should do it as follows:
> 
> At the moment you make an instance of a class that has default definitions
> for one of its superclasses, and there is no corresponding instance for
> that class, we implicitly insert the specified default instance. If
> there are more instances to choose from at that point, we report an error. 

If I read this properly, the intent is to make the meaning of the
program depend on the order in which it is compiled.  A good design
will make the meaning of a program depend only on the program text.
-- P