X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcMType.lhs;h=f01d69db55cdbcf129ee6e18ac21ea54b60d2de5;hb=0d2346b4f52de431e6274795307759cad47f0ea8;hp=23c3381581a2dd4a62b1b1e9597bf8e335e7f161;hpb=44ba24dc84d271ca9bd5ab5060cb63ed87f585e3;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcMType.lhs b/compiler/typecheck/TcMType.lhs
index 23c3381..f01d69d 100644
--- a/compiler/typecheck/TcMType.lhs
+++ b/compiler/typecheck/TcMType.lhs
@@ -368,7 +368,8 @@ data LookupTyVarResult	-- The result of a lookupTcTyVar call
 
 lookupTcTyVar :: TcTyVar -> TcM LookupTyVarResult
 lookupTcTyVar tyvar 
-  = case details of
+  = ASSERT( isTcTyVar tyvar )
+    case details of
       SkolemTv _   -> return (DoneTv details)
       MetaTv _ ref -> do { meta_details <- readMutVar ref
 			 ; case meta_details of