#7775: Mark intentionally omitted type class instances --------------------------------------------+------------------------------ Reporter: Lemming | Owner: Type: feature request | Status: closed Priority: normal | Milestone: Component: Compiler (Type checker) | Version: 7.7 Resolution: wontfix | Keywords: instance Operating System: Unknown/Multiple | warning Type of failure: None/Unknown | Architecture: Test Case: | Unknown/Multiple Blocking: | Difficulty: Unknown | Blocked By: | Related Tickets: --------------------------------------------+------------------------------ Changes (by Lemming): * version: 7.6.2 => 7.7 Comment: There is still a difference between intentionally and unintentionally omitted instances. I find it important to document for me and for others why I have omitted an instance. Also without the "possible fix" message people keep asking why an obvious instance is missing. "Why is this parser not Monoid?" - maybe because there are different ways of viewing it as Monoid. "Why is this identifier type not Num?" - maybe because it makes no sense to multiply identifiers. Or even worse, people do not just ask but start writing (conflicting) orphan instances. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7775#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler