#14180: Strange/bad error message binding unboxed type variable -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.2.3 Component: Compiler (Type | Version: 8.3 checker) | Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj):
For some reason, GHC expects the type of all type variables to have kind Type
It's here in `TcMType`: {{{ newMetaKindVar = do { uniq <- newUnique ; details <- newMetaDetails TauTv ; let kv = mkTcTyVar (mkKindName uniq) liftedTypeKind details ; traceTc "newMetaKindVar" (ppr kv) ; return (mkTyVarTy kv) } }}} When we see `forall a. blah`, we give `a` the kind `\kappa : *`. Richard may want to comment on why. It'd be good to add a Note to explain. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14180#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler