#12966: GHC panics with forall and constraint -------------------------------------+------------------------------------- Reporter: xcmw | Owner: Type: bug | Status: closed Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Resolution: wontfix | 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: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => closed * resolution: => wontfix * milestone: => 8.2.1 Comment: Thanks for the report, xcmw! On `master` this expectedly fails with, {{{ λ> :set -XRankNTypes λ> type Maybeify c = forall d. (c d) => ((~) (Maybe d)) <interactive>:3:39: error: • Expecting one more argument to ‘(~) (Maybe d)’ Expected a type, but ‘(~) (Maybe d)’ has kind ‘* -> Constraint’ • In the type ‘forall d. (c d) => ((~) (Maybe d))’ In the type declaration for ‘Maybeify’ }}} This was likely fixed by #11660, which won't be backported to 8.0. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12966#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler