X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcUnify.lhs;h=064f19956a58e5ee2c55e8fe3e88238c1d622e27;hb=dc07de316fa7730abe8759b57bd8300e07650f3a;hp=743320554d4da368e15d4ec49c24a77da868eaea;hpb=9d0c8f842e35dde3d570580cf62a32779f66a6de;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcUnify.lhs b/compiler/typecheck/TcUnify.lhs
index 7433205..064f199 100644
--- a/compiler/typecheck/TcUnify.lhs
+++ b/compiler/typecheck/TcUnify.lhs
@@ -578,9 +578,10 @@ boxy_match tmpl_tvs orig_tmpl_ty boxy_tvs orig_boxy_ty subst
 
     go ty1 ty2          -- C.f. the isSigmaTy case for boxySubMatchType
         | isSigmaTy ty1
-        , (tvs1, _, tau1) <- tcSplitSigmaTy ty1
-        , (tvs2, _, tau2) <- tcSplitSigmaTy ty2
+        , (tvs1, ps1, tau1) <- tcSplitSigmaTy ty1
+        , (tvs2, ps2, tau2) <- tcSplitSigmaTy ty2
         , equalLength tvs1 tvs2
+        , equalLength ps1  ps2
         = boxy_match (tmpl_tvs `delVarSetList` tvs1)    tau1
                      (boxy_tvs `extendVarSetList` tvs2) tau2 subst