#11145: Template Haskell quotes of data instance GADTs is totally broken -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.10.2 Resolution: | Keywords: GADTs 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 bollmann): while this problem persists in `7.10.3`, it is not present in `HEAD` (aea1e5db...) anymore. In the latter, the raised error is: {{{ ghc-stage2 Fuggle.hs -XTemplateHaskell -ddump-splices [1 of 1] Compiling Fuggle ( Fuggle.hs, Fuggle.o ) Fuggle.hs:(9,1)-(10,44): Splicing declarations [d| data instance Fuggle Int (Maybe (a_ap6, b_ap7)) where MkFuggle_ap5 :: Fuggle Int (Maybe Bool) |] ======> data instance Fuggle Int (Maybe (a_a4RB, b_a4RC)) where MkFuggle_a4RA :: Fuggle Int (Maybe Bool) Fuggle.hs:9:1: error: • Data constructor ‘MkFuggle’ returns type ‘Fuggle Int (Maybe Bool)’ instead of an instance of its parent type ‘Fuggle Int (Maybe (a_a4RB, b_a4RC))’ • In the definition of data constructor ‘MkFuggle’ In the data instance declaration for ‘Fuggle’ }}} So it seems to have been fixed (I don't know whether it was Phab:D1465 or something else, though) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11145#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler