#15839: DerivingStrategies defaulting warning has no associated enable/suppress flag -------------------------------------+------------------------------------- Reporter: tejon | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Poor/confusing Unknown/Multiple | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- When `DerivingStrategies`, `DeriveAnyClass` and `GeneralizedNewtypeDeriving` are enabled together, an instance that could be derived with either `newtype` or `anyclass` throws a warning when no strategy is specified. It appears to be impossible to suppress this warning. Even `-w` doesn't work! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15839 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler