[commit: ghc] master: Comments only (b10a768)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/b10a768786f93d174b1cbc64ae8dae4fe60120bf/ghc

>---------------------------------------------------------------

commit b10a768786f93d174b1cbc64ae8dae4fe60120bf
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Mon Oct 23 09:08:16 2017 +0100

    Comments only


>---------------------------------------------------------------

b10a768786f93d174b1cbc64ae8dae4fe60120bf
 compiler/typecheck/TcType.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/typecheck/TcType.hs b/compiler/typecheck/TcType.hs
index 7b27ce1..75e0215 100644
--- a/compiler/typecheck/TcType.hs
+++ b/compiler/typecheck/TcType.hs
@@ -936,9 +936,9 @@ anyRewritableTyVar ignore_cos role pred ty
     go_tc ReprEq bvs tc tys = foldr ((&&) . go_arg bvs) False $
                               (tyConRolesRepresentational tc `zip` tys)
 
-    go_arg _   (Phantom,          _)  = False  -- ToDo: check
     go_arg bvs (Nominal,          ty) = go NomEq  bvs ty
     go_arg bvs (Representational, ty) = go ReprEq bvs ty
+    go_arg _   (Phantom,          _)  = False  -- We never rewrite with phantoms
 
     go_co rl bvs co
       | ignore_cos = False