From 58f1518398346a81ccd8d0b14a14565b8bff5276 Mon Sep 17 00:00:00 2001
From: acondolu <andrea.condoluci@unibo.it>
Date: Thu, 13 Jul 2017 19:05:39 +0200
Subject: [PATCH] Fix: missing check to avoid stepping on vars of non positive
 arity

---
 ocaml/lambda4.ml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ocaml/lambda4.ml b/ocaml/lambda4.ml
index 9ed3394..6ceb9f3 100644
--- a/ocaml/lambda4.ml
+++ b/ocaml/lambda4.ml
@@ -571,7 +571,10 @@ let choose_step (n,p) =
        prerr_endline ("INSTANTIATING AND HOPING " ^ string_of_var x);
        x
   with
-   Not_found -> x in
+   Not_found ->
+    let arity_of_x = max_arity_tms x (all_terms p) in
+    assert (Util.option_get arity_of_x > 0); 
+    x in
 (* Instantiate in decreasing order of compute_special_k
 1:15m14s 2:13m14s 3:4m55s 4:4m43s 5:4m34s 6:6m28s 7:3m31s
 let x =
-- 
2.39.2