#15989: Adding extra quantified constraints leads to resolution failure -------------------------------------+------------------------------------- Reporter: eror | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.3 Component: Compiler (Type | Version: 8.6.2 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by eror): (Why do I want to use a constraint like this in the first place? I discovered this while trying to write something like {{{ ( forall x x'. x ~ x' => MonadReader (Env x) (m x') , forall x. MonadWriter Log (m x) ) }}} where the two type variables and equality constraint are there to work around #15351.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15989#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler