#11452: Typed Template Haskell sneakily allows impredicativity -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): Actually, my original example is OK; that's not impredicative, because the `a` can be bound outside the splice. But the following is accepted and really is impredicative: {{{#!hs {-# LANGUAGE RankNTypes, TemplateHaskell #-} module Bug where impred :: (forall a. a -> a) -> () impred = $$( [|| \_ -> () ||] ) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11452#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler