#14160: Type inference breaking change in GHC 8.0.2 -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: | ImpredicativeTypes 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): Agreed that this is an "improvement" (as in, GHC is behaving closer to spec) from previous behavior. Yes to allowing polytypes in visible type arguments. No to accepting `g = undefined`. It's impredicative! :) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14160#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler