#11062: Type families + hs-boot files = panic -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: patch Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 7.11 Resolution: | Keywords: TypeFamilies | hs-boot Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2215 Wiki Page: | -------------------------------------+------------------------------------- Comment (by ezyang): I attempted to do (2) but actually it is not that easy. The difficulty stems from the fact that some of the functions that query FamInstEnv, e.g., `normaliseType :: FamInstEnvs -> Role -> Type -> (Coercion, Type)` never fail; that is, they assume that there are no conflicting instances. So it would seem all of these functions would need to have their signatures changed that they might fail due to a conflicting instance. Might be worth it, but certainly not a non-invasive change. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11062#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler