#8177: Roles for type families -------------------------------------+------------------------------------- Reporter: simonpj | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by dmcclean): Yes. I was badly confused when I wrote that comment, sorry. See 9580 for where I broke this out as requested by goldfire. It turns out that the rule is indeed supposed to be that you can only do this coercion when `Quantity'` is in scope, which makes sense because that is when you could do it longhand, but that 7.8.3 currently implements a more lenient unintentional rule that also lets you do it (at least sometimes?) when you only have the data family in scope. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8177#comment:25 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler