#10896: BadSock triggers failing ASSERT -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler (Type | Version: 7.11 checker) | Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: indexed- | types/should_fail/BadSock Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1260 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones <simonpj@…>): In [changeset:"924f851700ca9ba7e0e7483b7ca4de62a4a74e15/ghc" 924f8517/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="924f851700ca9ba7e0e7483b7ca4de62a4a74e15" Refactor default methods (Trac #11105) This patch does some signficant refactoring to the treatment of default methods in class declarations, and more generally to the type checking of type/class decls. Highlights: * When the class has a generic-default method, such as class C a where op :: a -> a -> Bool default op :: Ord a => a -> a -> a the ClassOpItem records the type of the generic-default, in this case the type (Ord a => a -> a -> a) * I killed off Class.DefMeth in favour of the very-similar BasicTypes.DefMethSpec. However it turned out to be better to use a Maybe, thus Maybe (DefMethSpec Type) with Nothing meaning "no default method". * In TcTyClsDecls.tcTyClGroup, we used to accumulate a [TyThing], but I found a way to make it much simpler, accumulating only a [TyCon]. Much less wrapping and unwrapping. * On the way I also fixed Trac #10896 in a better way. Instead of killing off all ambiguity checks whenever there are any type errors (the fix in commit 8e8b9ed), I instead recover in TcTyClsDecls.checkValidTyCl. There was a lot of associated simplification all round }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10896#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler