#11450: Associated types at wrong type in instance -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #11449, #11451 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * related: => #11449, #11451 Comment: Oh, I wasn't aware of #11449 and #11451. Those are pretty important context for navigating this. I don't have any objection (in principle) to requiring that the class instance types be the same as the associate types. All I ask is please allow me to write something like this if I want to: {{{#!hs instance C (Either a _) where type T (Either a _) = a }}} I'm quite fond of using wildcard types wherever possible, and I'd hate to lose that due to this issue. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11450#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler