#10817: Looping default associated type family without UndecidableInstances -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- When I say {{{ {-# LANGUAGE TypeFamilies #-} module Bug where import Data.Proxy class C a where type F a type F a = F a instance C Bool x :: Proxy (F Bool) x = Proxy }}} GHC just loops. Setting a low `-ftype-function-depth` doesn't help. I actually don't terribly mind the looping (although aborting with an overflow would be better). But I don't like that it's possible without `UndecidableInstances` in sight. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10817 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler