[commit: packages/ghc-prim] master: Refer to the coercible paper in Coercible' docs (fc7aaf5)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/fc7aaf57a33ab07b70628c75fcf134fdf4e701e5/ghc-prim

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

commit fc7aaf57a33ab07b70628c75fcf134fdf4e701e5
Author: Joachim Breitner <mail at joachim-breitner.de>
Date:   Fri Mar 14 12:41:46 2014 +0100

    Refer to the coercible paper in Coercible' docs
    
    Implements parts of #8888.


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

fc7aaf57a33ab07b70628c75fcf134fdf4e701e5
 GHC/Types.hs |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/GHC/Types.hs b/GHC/Types.hs
index 3023045..a144657 100644
--- a/GHC/Types.hs
+++ b/GHC/Types.hs
@@ -162,6 +162,10 @@ data (~) a b = Eq# ((~#) a b)
 --
 --      @type role Set nominal@
 --
+--      For more details about this feature, please refer to
+--      <http://www.cis.upenn.edu/~eir/papers/2014/coercible/coercible.pdf Safe Coercions>
+--      by Joachim Breitner, Richard A. Eisenberg, Simon Peyton Jones and Stephanie Weirich.
+--
 --      /Since: 4.7.0.0/
 data Coercible a b = MkCoercible ((~#) a b)
 -- Also see Note [Kind-changing of (~) and Coercible]