[commit: ghc] master: Fix bug in expandTypeSynonyms that could rarely cause problems (4674a23)

[Max Bolingbroke]

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/4674a239687c8ea4a65be89b5d6ca09b78bf918f

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

commit 4674a239687c8ea4a65be89b5d6ca09b78bf918f
Author: Max Bolingbroke <batterseapower at hotmail.com>
Date:   Thu May 10 09:46:04 2012 +0100

    Fix bug in expandTypeSynonyms that could rarely cause problems

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

 compiler/types/Type.lhs |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index f81aebb..62cc7bb 100644
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -285,7 +285,7 @@ expandTypeSynonyms ty
       = TyConApp tc (map go tys)
     go (LitTy l)       = LitTy l
     go (TyVarTy tv)    = TyVarTy tv
-    go (AppTy t1 t2)   = AppTy (go t1) (go t2)
+    go (AppTy t1 t2)   = mkAppTy (go t1) (go t2)
     go (FunTy t1 t2)   = FunTy (go t1) (go t2)
     go (ForAllTy tv t) = ForAllTy tv (go t)
 \end{code}