#16139: GHC confused about type synonym kind with QuantifiedConstraints -------------------------------------+------------------------------------- Reporter: Ashley Yakeley | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 Resolution: | Keywords: 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): You can work around this by annotating the result with a kind signature: {{{#!hs {-# LANGUAGE KindSignatures, RankNTypes, ConstraintKinds, QuantifiedConstraints #-} module Bug where import Data.Kind type E = (forall (a :: *). Eq a => Num a :: Constraint) }}} (FWIW, I am also confused as to why GHC doesn't just accept your definition as-is.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16139#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler