#16140: Cannot create type synonym for quantified constraint without ImpredicativeTypes -------------------------------------+------------------------------------- Reporter: Ashley Yakeley | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 Resolution: | Keywords: | QuantifiedConstraints, | ImpredicativeTypes Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Replying to [comment:15 simonpj]:
* `checkValidType` uses `check_type`, not `check_pred_ty`.
I'm confused—didn't you say (in comment:3) that `checkValidType` should use `check_pred_ty` for `Constraint`-kinded things? (Now that I think about it, this is exactly why these errors are popping up—VTA simply didn't go down the `check_pred_ty` path before.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16140#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler