#10749: Boot file instances should imply superclasses -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Resolution: | Keywords: backpack Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by ezyang): * priority: low => normal Comment: Something that I've noticed is that (1) is not consistent with how superclasses work. For example, if I say: `Ord a => a -> a -> Bool`, I DO get an `Eq` instance in scope (because Eq is a superclass of Ord). So in practice, when I'm writing instances for modules in Backpack, I end up having to list a lot of instances, e.g., `Functor`, `Applicative`, `Monad`, `MonadFix`, etc. when, in the source code I was looking at, there was only `MonadFix`. Food for thought. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10749#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler