#11251: isInstance does not work on Typeable with base-4.8 anymore -------------------------------------+------------------------------------- Reporter: songzh | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.10.1 Resolution: | Keywords: Typeable, | isInstance Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): FWIW, there is already a warning for this sort of thing in the form of `-Wderiving-typeable`: {{{ $ ghci Bug.hs -Wderiving-typeable GHCi, version 8.2.1: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Main ( Bug.hs, interpreted ) Bug.hs:6:1: warning: [-Wderiving-typeable] • Deriving ‘Typeable’ has no effect: all types now auto-derive Typeable • In the stand-alone deriving instance for ‘Typeable TT’ | 6 | deriving instance Typeable TT | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Bug.hs:8:1: warning: [-Wderiving-typeable] • Deriving ‘Typeable’ has no effect: all types now auto-derive Typeable • In the stand-alone deriving instance for ‘Typeable TT’ | 8 | deriving instance Typeable TT | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ }}} Why this isn't enabled in `-Wall` is beyond me. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11251#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler