class.c: allow nil keyword_hash

* class.c (rb_extract_keywords): treat nil keyword_hash same as 0,
  for the case rb_scan_args returns nil if no keyword hash.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44702 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sat Jan 25 11:16:19 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* class.c (rb_extract_keywords): treat nil keyword_hash same as 0,
+	  for the case rb_scan_args returns nil if no keyword hash.
+
 Fri Jan 24 15:13:20 2014  Zachary Scott  <e@zzak.io>
 
 	* lib/racc/rdoc/grammar.en.rdoc: [DOC] Correct grammar and typos

class.c

@@ -1912,6 +1912,8 @@ rb_get_kwargs(VALUE keyword_hash, const ID *table, int required, int optional, V
      st_delete(rb_hash_tbl_raw(keyword_hash), &key, (val)) : \
      st_lookup(rb_hash_tbl_raw(keyword_hash), key, (val)))
 
+    if (NIL_P(keyword_hash)) keyword_hash = 0;
+
     if (optional < 0) {
 	rest = 1;
 	optional = -1-optional;