#7826: GHC internal error: `a' is not in scope during type checking, but it passed the renamer --------------------------------------+------------------------------------- Reporter: guest | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.6.2 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: GHC rejects valid program | Blockedby: Blocking: | Related: --------------------------------------+------------------------------------- In the attached code the following lines give an internal GHC error. At least this should not happen. I also think this is valid code. Removing either type annotation makes this code compile. {{{ bug :: WrappedR Int -> SomeFunction bug (Wrap node) = case node of (Memo' (emptyT :: t a b) memoize (Var m) :: R' a b Int) -> -- also breaks }}} {{{ /Users/alessandro/Documents/Uni/thesis/test/bug-tvar-passed- renamer.hs:14:104: GHC internal error: `a' is not in scope during type checking, but it passed the renamer tcl_env of environment: [(am4, Identifier[node::R' a b Int, <NotTopLevel>, 1]), (rgs, Identifier[bug::WrappedR Int -> SomeFunction, <NotTopLevel>, 1])] In the type `R' a b Int' In a pattern type signature: R' a b Int In the pattern: Memo' (emptyT :: t a b) (memoize :: MVar (t a b) -> (a -> b) -> a -> b) (Var m :: R' a b Int) :: R' a b Int }}} -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7826 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler