+withSavedSession :: GhcMonad m => m a -> m a
+withSavedSession m = do
+ saved_session <- getSession
+ m `gfinally` setSession saved_session
+
+-- | Call an action with a temporarily modified Session.
+withTempSession :: GhcMonad m => (HscEnv -> HscEnv) -> m a -> m a
+withTempSession f m =
+ withSavedSession $ modifySession f >> m
+