#9968: DeriveAnyClass fails on multi-parameter type classes -------------------------------------+------------------------------------- Reporter: goldfire | Owner: dreixel Type: bug | Status: new Priority: high | Milestone: 7.12.1 Component: Compiler | Version: 7.10.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #9821 | Differential Revisions: -------------------------------------+------------------------------------- Comment (by rwbarton): I think it's best to keep the simple rule: `data X = ... deriving (..., c, ...)` means to derive `c X` (here `c` is an application of a class constructor to zero or more types). After all if you want something else like `C X Bool` then you can express that with a standalone deriving declaration `deriving instance C X Bool`. Or in this case just write an empty instance, it's shorter :) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9968#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler