1 files changed, 3 insertions, 0 deletions
diff --git a/regcomp.c b/regcomp.c
index 43b51648eb..50b1080c98 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -471,6 +471,9 @@ I32 *flagp;
 		nextchar();
 		*flagp = TRYAGAIN;
 		return NULL;
+            case 0:
+                croak("Sequence (? incomplete");
+                break;
 	    default:
 		--regparse;
 		while (*regparse && strchr("iogcmsx", *regparse))