1 files changed, 10 insertions, 8 deletions
diff --git a/io.c b/io.c
index e4084e7104..de5e6cf136 100644
--- a/io.c
+++ b/io.c
@@ -4461,14 +4461,16 @@ rb_open_file(int argc, VALUE *argv, VALUE io)
     int flags;
     unsigned int fmode;
 
-    opt = rb_check_convert_type(argv[argc-1], T_HASH, "Hash", "to_hash");
-    if (!NIL_P(opt)) {
-	VALUE v;
-	v = rb_hash_aref(opt, sym_mode);
-	if (!NIL_P(v)) vmode = v;
-	v = rb_hash_aref(opt, sym_perm);
-	if (!NIL_P(v)) perm = v;
-	argc -= 1;
+    if (0 < argc) {
+        opt = rb_check_convert_type(argv[argc-1], T_HASH, "Hash", "to_hash");
+        if (!NIL_P(opt)) {
+            VALUE v;
+            v = rb_hash_aref(opt, sym_mode);
+            if (!NIL_P(v)) vmode = v;
+            v = rb_hash_aref(opt, sym_perm);
+            if (!NIL_P(v)) perm = v;
+            argc -= 1;
+        }
     }
 
     rb_scan_args(argc, argv, "12", &fname, &vmode, &perm);