> Ambiguous uses of multi-param type classes are sometimes silently turned
> into Void instances, instead of giving an error message.
Great bug report: brief, precise, and with a short program
demonstrating the problem. Thank you.
The difficulty was with functions like this:
f :: forall a. C a b => a -> a
Here the "b" part is ambiguous, but I was wrongly relying
on ambiguous constraints never getting "caught" by a forall.
But in the multi-param case then can.
This bug will be squashed today.
Simon
