===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/mandoc/eqn_term.c,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- src/usr.bin/mandoc/eqn_term.c	2015/01/01 15:34:43	1.4
+++ src/usr.bin/mandoc/eqn_term.c	2017/02/12 14:13:23	1.5
@@ -1,7 +1,7 @@
-/*	$OpenBSD: eqn_term.c,v 1.4 2015/01/01 15:34:43 schwarze Exp $ */
+/*	$OpenBSD: eqn_term.c,v 1.5 2017/02/12 14:13:23 schwarze Exp $ */
 /*
  * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2014, 2015 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2014, 2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -66,8 +66,10 @@
 
 	if (bp->pos == EQNPOS_SQRT) {
 		term_word(p, "sqrt");
-		p->flags |= TERMP_NOSPACE;
-		eqn_box(p, bp->first);
+		if (bp->first != NULL) {
+			p->flags |= TERMP_NOSPACE;
+			eqn_box(p, bp->first);
+		}
 	} else if (bp->type == EQN_SUBEXPR) {
 		child = bp->first;
 		eqn_box(p, child);
@@ -91,7 +93,8 @@
 		}
 	} else {
 		child = bp->first;
-		if (bp->type == EQN_MATRIX && child->type == EQN_LIST)
+		if (bp->type == EQN_MATRIX &&
+		    child != NULL && child->type == EQN_LIST)
 			child = child->first;
 		while (child != NULL) {
 			eqn_box(p,