#8423: contraint solver doesn't reduce reducible closed type family expressions (even with undecidable instances!) --------------------------------------------+------------------------------ Reporter: carter | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler (Type checker) | Version: 7.7 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: #4259 --------------------------------------------+------------------------------ Comment (by carter): thanks! this is great! Would I want to compare the core? (or just use criterion to benchmark?). I'll add that to my infinite todo list. This example seems to work only in ghc 7.8, how would i adapt those ideas to work on 7.6? (can I even?) that said, having more examples like this about how to prove things in haskell is probably a good idea! Also, figuring out how to erase such proofs as much as possible also would likely be worth while. I'm happy to help contribute a few braincells to chewing on that post 7.8 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8423#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler