--- /dev/null
+#!perl -w
+BEGIN{ $^P = 0x10 | 0x200 }
+use Test::More;
+
+sub DB::DB {}
+
+{
+ package Foo;
+ use Mouse;
+
+ __PACKAGE__->meta->add_method(bar => sub{ __LINE__ });
+}
+
+if(Mouse::Util::MOUSE_XS){
+is $DB::sub{'Foo::bar'}, sprintf('%s:%d-%d', __FILE__, Foo->bar, Foo->bar),
+ '%DB::sub updated';
+}
+else{
+ pass 'under Mouse::PurePerl';
+}
+
+done_testing;