#12239: Dependent type family does not reduce -------------------------------------+------------------------------------- Reporter: int-index | Owner: goldfire Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler (Type | Version: 8.0.1 checker) | Keywords: TypeInType, Resolution: | TypeFamilies Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: #11348 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * related: => #11348 Comment: Int-index and I have been working through this together this afternoon and it is nothing to do with what Richard initially expected. Instead, the problem is that whilst checking the kind of the argument to `FieldType`, we need knowledge of the instances of `FieldCount` which only get added to the environment *after* all the type family instances have been type checked. So instead this ticket is related to #11348. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12239#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler