#9569: Tuple constraints don't work right -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Resolution: fixed | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | polykinds/T9569, | typecheck/should_compile/T9569a | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by basvandijk): Maintainer of `monad-control` here. Do I get the following right (I haven't looked at this in detail yet): To work around not having to use the unstable `ImpredicativeTypes` I should turn the [https://github.com/basvandijk/monad- control/blob/master/Control/Monad/Trans/Control.hs#L143 Run] type synonym into a `newtype`. Then at every call site of [https://github.com/basvandijk/monad- control/blob/master/Control/Monad/Trans/Control.hs#L127 liftWith] I need to unwrap the `newtype` to be able to apply the inner function. ? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9569#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler