#14175: Panic repSplitTyConApp_maybe -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: 8.2.2 Component: Compiler (Type | Version: 8.2.1 checker) | Resolution: fixed | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: indexed- crash or panic | types/should_fail/T14175 Blocked By: | Blocking: Related Tickets: #13910 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): After this patch, GHC HEAD gives this error for the program in comment:2: {{{ Bug.hs:11:3: error: • Expected kind ‘(k -> *) -> (k -> *) -> *’, but ‘CD :: (k -> *) -> (k -> *) -> *’ has kind ‘Maybe a -> Maybe a -> *’ • In the data instance declaration for ‘CD’ In the instance declaration for ‘C (Maybe a)’ | 11 | data CD :: (k -> *) -> (k -> *) -> * | ^^^^^^^ }}} And this error for the program in comment:4: {{{ Bug.hs:13:3: error: • Expected kind ‘(k -> *) -> *’, but ‘CD k (a :: k -> *) :: (k -> *) -> *’ has kind ‘k -> *’ • In the data instance declaration for ‘CD’ In the instance declaration for ‘C (Maybe a)’ | 13 | data CD k (a :: k -> *) :: (k -> *) -> * | ^^^^^^^^^^^^^^^^^^^^^^^ }}} As you observed, these error messages aren't great and could likely be improved. Should I open a separate ticket for this? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14175#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler