#13806: Invalid usage of TypeFamilies cause GHC Internal Error -------------------------------------+------------------------------------- Reporter: utdemir | Owner: (none) Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by utdemir: @@ -1,3 +1,3 @@ - I couldn't be able to reproduce this with a valid program, but seeing "GHC - internal error" was surprising. Only the second error should be enough in - this case. + I couldn't be able to reproduce this with a valid program, but even on an + invalid program seeing "GHC internal error" is unexpected. Only the second + error should be enough in this case. New description: I couldn't be able to reproduce this with a valid program, but even on an invalid program seeing "GHC internal error" is unexpected. Only the second error should be enough in this case. {{{ $ cat test.hs {-# LANGUAGE TypeFamilies #-} data Foo value = Foo (T value) class Cl t where type T mk :: t -> T main :: IO () main = undefined $ runhaskell test.hs test.hs:4:10: error: • GHC internal error: ‘T’ is not in scope during type checking, but it passed the renamer tcl_env of environment: [a10K :-> Type variable ‘value’ = value, r10F :-> ATcTyCon Foo, r10G :-> APromotionErr RecDataConPE] • In the type ‘T value’ In the definition of data constructor ‘Foo’ In the data declaration for ‘Foo’ test.hs:6:1: error: • The associated type ‘T’ mentions none of the type or kind variables of the class ‘Cl t’ • In the class declaration for ‘Cl’ $ runhaskell --version runghc 8.0.2 }}} -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13806#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler