#11250: GHC shows core with error -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect Unknown/Multiple | warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following code intentionally does not compile: {{{ {-# LANGUAGE DataKinds, KindSignatures, PolyKinds #-} data Proxy (p :: k) = Proxy data Tagged (t :: k) s = Tagged s proxy :: Tagged t s -> Proxy t -> s proxy = undefined bar :: Tagged (gad :: *) Int bar = undefined foo :: Int foo = proxy bar (Proxy::Proxy 'True) }}} but it produces the following output with GHC and GHCi: {{{ [1 of 1] Compiling Main ( Bug.hs, interpreted ) RAE1 [W] cobox_aLM :: t0_aK4[tau:1] ~ 'True (CNonCanonical) t0_aK4[tau:1] 'True False Bug.hs:13:18: Couldn't match kind ‘Bool’ with ‘*’ Expected type: Proxy t0 Actual type: Proxy 'True In the second argument of ‘proxy’, namely ‘(Proxy :: Proxy True)’ In the expression: proxy bar (Proxy :: Proxy True) In an equation for ‘foo’: foo = proxy bar (Proxy :: Proxy True) Failed, modules loaded: none. }}} This ticket is about the first block printed out. It seems to be a random section of core, and is completely useless to debugging the problem. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11250 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler