#10432: panic with kind polymorphism -------------------------------------+------------------------------------- Reporter: Ashley Yakeley | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.10.1 checker) | Keywords: Resolution: | Architecture: Operating System: Unknown/Multiple | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by simonpj): This works in HEAD, but another variant makes HEAD, too, fail in the same way `No skolem info`: {{{ matchReflK2 :: forall (a :: ka) (b :: kb) (r :: *). ('WrapType a :~: 'WrapType b) -> r matchReflK2 x = let foo :: ('WrapType a ~ 'WrapType b) => r foo = undefined in undefined }}} Reason: the type of `foo` mentions `a`, `b`, `r` as free variables; the ambiguity check doesn't bind them; the error message generator falls over. Need to look into this. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10432#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler