#12081: TypeInType Compile-time Panic -------------------------------------+------------------------------------- Reporter: MichaelK | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc4 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I've been playing around with GHC 8.0.1-rc4 release and got a panic from the following (stripped down) code: {{{#!hs {-# LANGUAGE TypeInType #-} data Nat = Z | S Nat class C (n :: Nat) where type T n :: Nat f :: (a :: T n) }}} {{{ ghc: panic! (the 'impossible' happened) (GHC version 8.0.0.20160421 for x86_64-apple-darwin): isInjectiveTyCon sees a TcTyCon T }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12081 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler