[commit: ghc] master: Add fixity declaration for :~~: (ee9232524)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/ee9232524bdba5b268278ec51f30106bb7178ce9/ghc

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

commit ee9232524bdba5b268278ec51f30106bb7178ce9
Author: Ryan Scott <ryan.gl.scott at gmail.com>
Date:   Sun Jun 18 16:49:02 2017 -0400

    Add fixity declaration for :~~:
    
    We have one for `(:~:)`, but not for `(:~~:)`! Let's fix this
    oversight.
    
    Reviewers: bgamari, austin, hvr
    
    Reviewed By: bgamari
    
    Subscribers: rwbarton, thomie
    
    Differential Revision: https://phabricator.haskell.org/D3657


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

ee9232524bdba5b268278ec51f30106bb7178ce9
 libraries/base/Data/Type/Equality.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/base/Data/Type/Equality.hs b/libraries/base/Data/Type/Equality.hs
index 173e3c4..8cc34f6 100644
--- a/libraries/base/Data/Type/Equality.hs
+++ b/libraries/base/Data/Type/Equality.hs
@@ -77,7 +77,7 @@ instance {-# INCOHERENT #-} a ~~ b => a ~ b
   -- INCOHERENT because we want to use this instance eagerly, even when
   -- the tyvars are partially unknown.
 
-infix 4 :~:
+infix 4 :~:, :~~:
 
 -- | Propositional equality. If @a :~: b@ is inhabited by some terminating
 -- value, then the type @a@ is the same as the type @b at . To use this equality