#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): Thanks for the advice. I'm now using: {{{ mask :: MonadBaseControl IO m => ((forall a. m a -> m a) -> m b) -> m b mask f = control $ \runInBase -> E.mask $ \g -> runInBase $ f $ liftBaseOp_ g }}} without using `ImpredicativeTypes`. @luite I will make a point release of `lifted-base` with this fix. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9569#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler