Use bracket_ rather than bracket in withExtendedLinkEnv

compiler/ghci/Linker.lhs

@@ -293,22 +293,22 @@ linkDependencies hsc_env span needed_mods = do
 
 withExtendedLinkEnv :: [(Name,HValue)] -> IO a -> IO a
 withExtendedLinkEnv new_env action
-    = bracket set_new_env
-              reset_old_env
-              (const action)
+    = bracket_ set_new_env
+               reset_old_env
+               action
     where set_new_env = do 
             pls <- readIORef v_PersistentLinkerState
             let new_closure_env = extendClosureEnv (closure_env pls) new_env
                 new_pls = pls { closure_env = new_closure_env }
             writeIORef v_PersistentLinkerState new_pls
-            return (closure_env pls)
+            return ()
 
         -- Remember that the linker state might be side-effected
         -- during the execution of the IO action, and we don't want to
         -- lose those changes (we might have linked a new module or
         -- package), so the reset action only removes the names we
         -- added earlier.
-          reset_old_env env = do
+          reset_old_env = do
             modifyIORef v_PersistentLinkerState $ \pls ->
                 let cur = closure_env pls
                     new = delListFromNameEnv cur (map fst new_env)