add test for [ruby-dev:31153].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12756 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

bootstraptest/test_block.rb

@@ -382,3 +382,12 @@ assert_equal 'nil', %q{
   m {|(v,(*))|}.inspect
 }
 
+
+# [ruby-dev:31153]
+assert_equal 'nil', %q{
+  def m()
+    yield
+  end
+  m {|(*,a,b)|}.inspect
+}
+