#8634: Relax functional dependency coherence check ("liberal coverage condition") -------------------------------------+------------------------------------- Reporter: danilo2 | Owner: Type: feature | Status: new request | Milestone: 7.10.1 Priority: high | Version: 7.7 Component: Compiler | Keywords: Resolution: | Operating System: Unknown/Multiple Differential Revisions: Phab:D69 | Type of failure: None/Unknown Architecture: | Test Case: Unknown/Multiple | Blocking: Difficulty: Unknown | Blocked By: | Related Tickets: #1241, | #2247, #8356, #9103, #9227 | -------------------------------------+------------------------------------- Comment (by simonpj): Incidentally, on the Phab comment stream, danilo2 says: I'm very attracted to the idea to be able to throw away liberage coverage condition - in some places it could give interesting effects (like IncoherentInstances). But in opposite to IncoherentInstances, I've got a real-life code, which is right now working using DysfunctionalDependencies and is working great. I and some people from the company I'm working in were thinking for a long time if we can replace a very special type class instance with other mechanisms and we came to a conclusion, that using this extension would be life saver for us - and this is the reason I started looking into ghc and implementing it. I would be very happy If you agree with me and would allow this extension to exist within GHC. I'm adding the comment in here by way of further motivation. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8634#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler