#11754: Error in optCoercion -------------------------------------+------------------------------------- Reporter: simonpj | Owner: goldfire Type: bug | Status: closed Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 8.1 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: | typecheck/should_compile/T11754 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed @@ -2,1 +2,1 @@ - {{{ + {{{#!hs New description: This program fails Lint after a run of the simplifier. {{{#!hs {-# LANGUAGE TypeOperators, UndecidableSuperClasses, KindSignatures, TypeFamilies, FlexibleContexts #-} module T11728a where import Data.Kind import Data.Void newtype K a x = K a newtype I x = I x data (f + g) x = L (f x) | R (g x) data (f × g) x = f x :×: g x class Differentiable (D f) => Differentiable f where type D (f :: Type -> Type) :: Type -> Type instance Differentiable (K a) where type D (K a) = K Void instance Differentiable I where type D I = K () instance (Differentiable f₁, Differentiable f₂) => Differentiable (f₁ + f₂) where type D (f₁ + f₂) = D f₁ + D f₂ instance (Differentiable f₁, Differentiable f₂) => Differentiable (f₁ × f₂) where type D (f₁ × f₂) = (D f₁ × f₂) + (f₁ × D f₂) }}} Originally reported in #11728, but it's a totally different problem. Richard has nailed it already... patch coming from him. -- Comment: Merged to `ghc-8.0` as 91a8e92606890ca191ca7227b11a95c9c76cb428. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11754#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler