#14332: Deriving clauses can have forall types -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.2.1 checker) | Resolution: | Keywords: deriving Operating System: Unknown/Multiple | Architecture: Type of failure: GHC accepts | Unknown/Multiple invalid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj):
Notice how the k has become * due to kind unification!
I'd say this is an outright bug. You should say {{{ data D = D deriving (C Type) }}} Would you like to open a ticket? I grant that it's odd to quantify over a type former. But it's odd not to have ANY way to explicitly quantify. (Well, I suppose you could use standalone deriving.) I'm not pressing hard for an explicit forall. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14332#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler