diff --git a/ChangeLog b/ChangeLog
index 45c58e7b76..f04c44d84b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Nov 18 09:42:11 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/optparse.rb (OptionParser::make_switch): makes default
+	  conversion to splat.  [ruby-list:45645]
+
 Mon Nov 17 18:05:16 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* enc/depend (LIBS): fixed for disable-shared.  [ruby-dev:37103]
diff --git a/lib/optparse.rb b/lib/optparse.rb
index 5a86194b7e..0548a29cac 100644
--- a/lib/optparse.rb
+++ b/lib/optparse.rb
@@ -996,6 +996,7 @@ class OptionParser
   end
   private :notwice
 
+  SPLAT_PROC = proc {|*a| a}
   #
   # Creates an OptionParser::Switch from the parameters. The parsed argument
   # value is passed to the given block, where it can be processed.
@@ -1076,7 +1077,11 @@ class OptionParser
       # directly specified pattern(any object possible to match)
       if (!(String === o || Symbol === o)) and o.respond_to?(:match)
         pattern = notwice(o, pattern, 'pattern')
-        conv = pattern.method(:convert).to_proc if pattern.respond_to?(:convert)
+        if pattern.respond_to?(:convert)
+          conv = pattern.method(:convert).to_proc
+        else
+          conv = SPLAT_PROC
+        end
         next
       end