[Haskell] type inference & instance extensions

Sittampalam, Ganesh ganesh.sittampalam at credit-suisse.com
Mon Jan 19 10:34:19 EST 2009

Lennart Augustsson wrote:

>> I had hoped that the code below (GHC 6.10+) would work, but it just
>> sends GHC into a loop when you actually try to typecheck (1,1). I
>> don't know if that's a bug in GHC or a misunderstanding on my part of
>> how the typechecking should work.

> A loop without turning on a flag to allow it must be a bug.

Sorry, I didn't mean to say "typecheck (1,1)". I meant to say
"evaluate (1,1)*(1,1)" - I had a suspicion that some kind of 
infinite polymorphic recursion through the Num instance is
happening and accidentally turned that thought into a
completely different statement.


Please access the attached hyperlink for an important electronic communications disclaimer: 


More information about the Haskell mailing list