1 files changed, 1 insertions, 1 deletions
diff --git a/string.c b/string.c
index 40207e5ba4..ff9e6bd0c2 100644
--- a/string.c
+++ b/string.c
@@ -1797,7 +1797,7 @@ trnext(t)
 	if (!t->gen) {
 	    if (t->p == t->pend) return -1;
 	    t->now = *(USTR)t->p++;
-	    if (t->p < t->pend && *t->p == '-') {
+	    if (t->p < t->pend - 1 && *t->p == '-') {
 		t->p++;
 		if (t->p < t->pend) {
 		    if (t->now > *(USTR)t->p) {