#8888: Document Coercible in user's guide -------------------------------------+------------------------------------ Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.8.1 Component: Documentation | Version: 7.8.1-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by simonpj): You've put a lot of work into this, and you may well be right. I'd welcome opinions from others. For now, though, even if the main documentation stays in the library Haddock stuff, could you * add a link to the paper (which gives far more background) to the Haddock docs * add a user-manual sub-section that summarises in one paragraph and points off to the Haddock docs That way people like me who look at the manual will still end up in the right place. I'm still puzzled about two things though. * `Data.Coerce` has {{{ import GHC.Prim (coerce, Coercible) }}} But `GHC.Prim` does not export `Coercible`.... it's defined in `GHC.Types`. So how does this even compile? * In the [http://www.haskell.org/ghc/docs/7.8.1-rc2/html/libraries/base-4.7.0.0 /Data-Coerce.html Haddock link you sent], `Coercible` shows as a class. But it's defined (in `GHC.Types` as a data type. I believe that happens by way of `TysWiredIn.coercibleTyCon` and `coercibleClass`, but it's quite hard to unravel, and definitely deserves a `Note` in `GHC.Types`, and or `TysWiredIn` (details in one place, a pointer in the other. It may well be that the way that `(~)` is handled needs similar documentation. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8888#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler