[commit: ghc] master: Don't print roles for data instances (0f7381b)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/0f7381bfb382f9fd7d18ebfc1a436237e6f2e21d/ghc

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

commit 0f7381bfb382f9fd7d18ebfc1a436237e6f2e21d
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Fri Jan 17 14:06:02 2014 +0000

    Don't print roles for data instances
    
    See Trac #8672


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

0f7381bfb382f9fd7d18ebfc1a436237e6f2e21d
 compiler/main/PprTyThing.hs               |    4 +++-
 testsuite/tests/ghci/scripts/T5417.stdout |    1 -
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/compiler/main/PprTyThing.hs b/compiler/main/PprTyThing.hs
index c83552b..38b28e9 100644
--- a/compiler/main/PprTyThing.hs
+++ b/compiler/main/PprTyThing.hs
@@ -209,7 +209,9 @@ pprTyCon ss tyCon
     pp_roles suppress_if
       = sdocWithDynFlags $ \dflags ->
         let roles = suppressKinds dflags (tyConKind tyCon) (tyConRoles tyCon)
-        in ppUnless (all suppress_if roles) $
+        in ppUnless (isFamInstTyCon tyCon || all suppress_if roles) $
+             -- Don't display roles for data family instances (yet)
+             -- See discussion on Trac #8672.
            ptext (sLit "type role") <+> ppr tyCon <+> hsep (map ppr roles)
 
     pp_tc_with_kind = vcat [ pp_roles (const True)
diff --git a/testsuite/tests/ghci/scripts/T5417.stdout b/testsuite/tests/ghci/scripts/T5417.stdout
index 2cf0826..73d1de9 100644
--- a/testsuite/tests/ghci/scripts/T5417.stdout
+++ b/testsuite/tests/ghci/scripts/T5417.stdout
@@ -1,5 +1,4 @@
 data B1 a = B1 a
-type role T5417.R:FB1 nominal
 data instance C.F (B1 a) = B2 a
 type role D nominal
 data family D a