Prefer rb_check_arity when 0 or 1 arguments

Especially over checking argc then calling rb_scan_args just to
raise an ArgumentError.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66238 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 1 deletions

diff --git a/thread_sync.c b/thread_sync.c
index e478a96b88..4a3cb2ad6a 100644
--- a/thread_sync.c
+++ b/thread_sync.c
@@ -517,7 +517,7 @@ mutex_sleep(int argc, VALUE *argv, VALUE self)
 {
     VALUE timeout;
 
-    rb_scan_args(argc, argv, "01", &timeout);
+    timeout = rb_check_arity(argc, 0, 1) ? argv[0] : Qnil;
     return rb_mutex_sleep(self, timeout);
 }