\begin{code}
module TcUnify where
-import TcType ( TcTauType )
+import TcType ( TcTauType, BoxyType )
import TcRnTypes( TcM )
-- This boot file exists only to tie the knot between
-- TcUnify and TcSimplify
-unifyTauTy :: TcTauType -> TcTauType -> TcM ()
+unifyType :: TcTauType -> TcTauType -> TcM ()
+zapToMonotype :: BoxyType -> TcM TcTauType
\end{code}