#11431: GHC instantiates levity-polymorphic type variables with foralls -------------------------------------+------------------------------------- Reporter: gridaphobe | Owner: 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): I think the current behavior is fine, if somewhat unexpected. (We should document it if we haven't.) There is no such thing as a levity-polymorphic value. (If there were, how much space would it take up?) Thus, any levity-polymorphic expression must be bottom. So I don't see how a tiny bit of impredicativity just for bottoms can cause trouble. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11431#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler