Hello, On Thu, Oct 11, 2012 at 3:54 PM, MigMit <miguelim...@yandex.ru> wrote: > You have a bigger problem coming. Some extensions make multiple instances OK, > even in Safe Haskell. For example: > > {-# LANGUAGE FlexibleInstances, IncoherentInstances, Safe #-} > [...]
Safe Haskell already disallows OverlappingInstances. If we add a requirement that it must be unambiguous which instance declaration a given type class constraint resolves to (taking into account instances defined in all modules), I think it will be necessary to also disallow IncoherentInstances. -- () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe