@@ -116,7 +116,7 @@ solve constraint =
117 CInstance name term -> do
117 CInstance name term -> do
118 env <- TS.getEnv
118 env <- TS.getEnv
119− freshCopy <- TS.makeInstance ((Map.!) env name)
119+ freshCopy <- TS.makeInstance (Map.findWithDefault (error $ "Could not find " ++ name ++ " in the environment") name env)
120 t <- TS.flatten term
120 t <- TS.flatten term
121 unify freshCopy t
121 unify freshCopy t
122 TS.getEnv
122 TS.getEnv