#13391: PolyKinds is more permissive in GHC 8 -------------------------------------+------------------------------------- Reporter: crockeea | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: Type of failure: GHC accepts | Unknown/Multiple invalid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * keywords: => newcomer Comment: Good catch. I suspect fixing this wouldn't be too challenging. If you look at the commitdiff for 6746549772c5cc0ac66c0fce562f297f4d4b80a2 (Add kind equalities to GHC), searching for `badGadtKindCon` will give you the check that used to be in place for catching datatypes that are GADT-like in their kind arguments. Fixing this issue should hopefully be a matter of reinstating that check, but guarded behind a check for the presence of `-XTypeInType`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13391#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler