diff --git a/ChangeLog b/ChangeLog
index f10efa34a6..6f4c652cba 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Dec 12 23:33:53 2006  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/optparse.rb (Switch#parse_arg, Switch#conv_arg): splat failures.
+
 Mon Dec 11 11:51:10 2006  Akinori MUSHA  <knu@iDaemons.org>
 
 	* ext/digest/sha2/lib/sha2.rb: Moved one level up from under
diff --git a/lib/optparse.rb b/lib/optparse.rb
index 4cab6928bb..91520479ef 100644
--- a/lib/optparse.rb
+++ b/lib/optparse.rb
@@ -321,10 +321,10 @@ class OptionParser
     # argument pattern. Yields when the pattern doesn't match substring.
     #
     def parse_arg(arg)
-      pattern or return nil, arg
+      pattern or return nil, [arg]
       unless m = pattern.match(arg)
         yield(InvalidArgument, arg)
-        return arg, nil
+        return arg, []
       end
       if String === m
         m = [s = m]
@@ -345,7 +345,7 @@ class OptionParser
     # conversion. Yields at semi-error condition instead of raising an
     # exception.
     #
-    def conv_arg(arg, val = nil)
+    def conv_arg(arg, val = [])
       if conv
         val = conv.call(*val)
       else