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