* I ''really'' don't think `Enum` belongs in 2(b), which is why I put a question mark on it in the first place. I think it should also be moved to
#10598: DeriveAnyClass and GND don't work well together -------------------------------------+------------------------------------- Reporter: osa1 | Owner: RyanGlScott Type: bug | Status: patch Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.11 Resolution: | Keywords: Generics Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2280 Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Replying to [comment:46 oerjan]: the bottom left cell in the table. I don't follow. Why should it be in the "never" category? As noted above, there are scenarios when GHC will derive `Enum` for newtypes, and they are perfectly captured in 2(b).
* Even though it's explained below, I have a hunch the phrase "bespoke typeclass instance" could be misinterpreted as referring to the selected strategy. It's a little longer, but "instance for a bespoke typeclass" feels less ambiguous.
* The paragraph starting "Step 2.(b) deserves some explanation." doesn't make sense with the new algorithm, since the issue no longer applies with
This is why I hate choosing syntax :) I'm going strictly by the dictionary definition of "bespoke" here, which means "tailor-made" or "custom-fit". That means the phrase "bespoke typeclass" doesn't make sense, since "bespoke" is a property of the instance, not the typeclass. the new control flow. (After all, one of the things simplifying it is that step 2 doesn't need to consider anyclass any more, and step 3 doesn't need to consider bespoke.) I've reworded it to make it a little clearer, hopefully. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10598#comment:47 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler