From 595bc2871d41efe68cec968862b89bfc58afbba6 Mon Sep 17 00:00:00 2001
From: Simon Huber <hubsim@gmail.com>
Date: Sat, 18 Apr 2015 13:49:45 +0200
Subject: [PATCH] lookName error msg for debugging

---
 Eval.hs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Eval.hs b/Eval.hs
index 9675865..7869b92 100644
--- a/Eval.hs
+++ b/Eval.hs
@@ -27,6 +27,7 @@ lookType x r@(Def rho r1) = case lookup x rho of
 lookType x (Sub rho _) = lookType x rho
 
 lookName :: Name -> Env -> Formula
+lookName i Empty       = error $ "lookName: not found " ++ show i
 lookName i (Upd rho _) = lookName i rho
 lookName i (Def _ rho) = lookName i rho
 lookName i (Sub rho (j,phi)) | i == j    = phi
-- 
2.34.1