#15431: Coercible and Existential types don't play nicely -------------------------------------+------------------------------------- Reporter: NioBium | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Resolution: | Keywords: Roles Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #14333 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones <simonpj@…>): In [changeset:"f0d27f515ffbc476144d1d1dd1a71bf9fa93c94b/ghc" f0d27f5/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="f0d27f515ffbc476144d1d1dd1a71bf9fa93c94b" Stop marking soluble ~R# constraints as insoluble We had a constraint (a b ~R# Int), and were marking it as 'insoluble'. That's bad; it isn't. And it caused Trac #15431. Soultion is simple. I did a tiny refactor on can_eq_app, so that it is used only for nominal equalities. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15431#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler