[commit: ghc] master: Comments only (9d3bd3d)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/9d3bd3dca889af558737282ad2509b32ded93e6a/ghc

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

commit 9d3bd3dca889af558737282ad2509b32ded93e6a
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Tue Apr 21 13:39:46 2015 +0100

    Comments only


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

9d3bd3dca889af558737282ad2509b32ded93e6a
 compiler/typecheck/TcFlatten.hs | 2 +-
 compiler/typecheck/TcMType.hs   | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/compiler/typecheck/TcFlatten.hs b/compiler/typecheck/TcFlatten.hs
index 89431f8..a5ece16 100644
--- a/compiler/typecheck/TcFlatten.hs
+++ b/compiler/typecheck/TcFlatten.hs
@@ -1744,7 +1744,7 @@ Note [Unflatten using funeqs first]
     [W] F (G a) ~ G a
 
 do not want to end up with
-    [W} F Int ~ Int
+    [W] F Int ~ Int
 because that might actually hold!  Better to end up with the two above
 unsolved constraints.  The flat form will be
 
diff --git a/compiler/typecheck/TcMType.hs b/compiler/typecheck/TcMType.hs
index 2fffcd4..0eaae8f 100644
--- a/compiler/typecheck/TcMType.hs
+++ b/compiler/typecheck/TcMType.hs
@@ -454,11 +454,16 @@ tcInstTyVarX subst tyvar
   = do  { uniq <- newUnique
         ; details <- newMetaDetails (TauTv False)
         ; let name   = mkSystemName uniq (getOccName tyvar)
+                       -- See Note [Name of an instantiated type variable]
               kind   = substTy subst (tyVarKind tyvar)
               new_tv = mkTcTyVar name kind details
         ; return (extendTvSubst subst tyvar (mkTyVarTy new_tv), new_tv) }
 
-{-
+{- Note [Name of an instantiated type variable]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+At the moment we give a unification variable a System Name, which
+influences the way it is tidied; see TypeRep.tidyTyVarBndr.
+
 ************************************************************************
 *                                                                      *
              Quantification