[only apply type constructor when it has a pi-type
John Meacham <john@repetae.net>**20060310015423] hunk ./E/Inline.hs 93
-app' (ELit (LitCons n xs t)) (a:as)  = do
+app' (ELit (LitCons n xs t@EPi {})) (a:as)  = do