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/error.c b/error.c
index b4ba64b57a..2e2cc25ac2 100644
--- a/error.c
+++ b/error.c
@@ -946,7 +946,7 @@ exc_initialize(int argc, VALUE *argv, VALUE exc)
 {
     VALUE arg;
 
-    rb_scan_args(argc, argv, "01", &arg);
+    arg = (!rb_check_arity(argc, 0, 1) ? Qnil : argv[0]);
     return exc_init(exc, arg);
 }