#9939: Warn for duplicate superclass constraints -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by goldfire): Another example I hit recently. `Language.Haskell.TH.Syntax` used to have {{{ class (Applicative m, Monad m) => Quasi m where ... }}} When I saw this recently, I realized the `Applicative m` constraint is now redundant and so I removed it. However, it would have been helpful if GHC had issued a warning. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9939#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler