[don't erase variables that bind type
John Meacham <john@repetae.net>**20070515005457] hunk ./E/SSimplify.hs 196
-    Nothing -> annb' tvr { tvrIdent = 0 }
-    Just _ -> annb' tvr
+    Nothing | sortTermLike (getType tvr) -> annb' tvr { tvrIdent = 0 }
+    _ -> annb' tvr