#11066: Inacessible branch should be warning - otherwise breaks type soundness? -------------------------------------+------------------------------------- Reporter: rrnewton | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: #8128, #8740 | Differential Rev(s): Phab:D1454 Wiki Page: | -------------------------------------+------------------------------------- Comment (by dfeuer): I wonder if ekmett's problem lies in the somewhat bogus type family definition: {{{#!hs type family Gcd :: Nat -> Nat -> Nat }}} An instance of the family would have to be a ''constructor'' of kind `Nat -> Nat -> Nat`. There is no such thing, so GHC may reject the notion under some circumstances. This is just speculation, though. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11066#comment:22 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler