#11364: Possible type-checker regression in GHC 8.0 -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: bug | Status: closed Priority: highest | Milestone: 8.0.1 Component: Compiler (Type | Version: 7.10.3 checker) | Resolution: invalid | 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 simonpj): You can make it compile by adding a signature to fix `e0` to be `ee`. For example: {{{ unthrow :: forall aa ee proxy. proxy ee -> (Throws ee => aa) -> aa unthrow _ x = unWrap (coerceWrap (Wrap x :: Wrap ee aa)) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11364#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler