From d97abb07637c7665413ee38357e257ac04367571 Mon Sep 17 00:00:00 2001
From: ceriel <none@none>
Date: Mon, 6 Mar 1989 18:48:30 +0000
Subject: [PATCH] avoid null-reference if some nonterminal is not defined

---
 util/LLgen/src/reach.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/util/LLgen/src/reach.c b/util/LLgen/src/reach.c
index 3fa5110da..5bc3e7c17 100644
--- a/util/LLgen/src/reach.c
+++ b/util/LLgen/src/reach.c
@@ -35,7 +35,6 @@ STATIC reachwalk();
 co_reach() {
 	/*
 	 * Check for undefined or unreachable nonterminals.
-	 * An undefined nonterminal is a fatal error!
 	 */
 	register p_nont		p;
 	register p_start	st;
@@ -50,6 +49,7 @@ co_reach() {
 				p->n_name);
 		}
 	}
+
 	/*
 	 * Walk the grammar rules, starting with the startsymbols
 	 * Mark the nonterminals that are encountered with the flag
@@ -106,7 +106,7 @@ reachwalk(p) register p_gram p; {
 			register p_nont n = &nonterms[g_getcont(p)];
 
 			reachable(n);
-			if (g_gettype(n->n_rule) == EORULE &&
+			if (p->n_rule && g_gettype(n->n_rule) == EORULE &&
 			    ! g_getnpar(p) && (getntparams(n) == 0)) {
 				register p_gram np = p;
 				do {
-- 
2.34.1