[commit: ghc] master: Define an Outputable MCoercion instance (6595bee)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/6595bee749ddb49d9058ed47ab7c1b6e7558ae17/ghc

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

commit 6595bee749ddb49d9058ed47ab7c1b6e7558ae17
Author: Ryan Scott <ryan.gl.scott at gmail.com>
Date:   Sun Jul 8 12:20:53 2018 -0400

    Define an Outputable MCoercion instance
    
    Summary: I needed this when debugging #15346.
    
    Test Plan: Does it compile? It does? Cool.
    
    Reviewers: bgamari, mpickering
    
    Reviewed By: mpickering
    
    Subscribers: rwbarton, thomie, carter
    
    GHC Trac Issues: #15311
    
    Differential Revision: https://phabricator.haskell.org/D4944


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6595bee749ddb49d9058ed47ab7c1b6e7558ae17
 compiler/types/TyCoRep.hs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/compiler/types/TyCoRep.hs b/compiler/types/TyCoRep.hs
index 7923369..0ec5888 100644
--- a/compiler/types/TyCoRep.hs
+++ b/compiler/types/TyCoRep.hs
@@ -964,6 +964,10 @@ data MCoercion
     -- Other coercions
 type MCoercionR = MCoercion
 
+instance Outputable MCoercion where
+  ppr MRefl    = text "MRefl"
+  ppr (MCo co) = text "MCo" <+> ppr co
+
 {-
 Note [Refl invariant]
 ~~~~~~~~~~~~~~~~~~~~~