diff --git a/test/bind_placeholder_test.cpp b/test/bind_placeholder_test.cpp
index 90ba2dd..174dd82 100644
--- a/test/bind_placeholder_test.cpp
+++ b/test/bind_placeholder_test.cpp
@@ -43,11 +43,16 @@ template< int I > struct custom_placeholder
 {
 };
 
-template< int I > struct boost::is_placeholder< custom_placeholder< I > >
+namespace boost
+{
+
+template< int I > struct is_placeholder< custom_placeholder< I > >
 {
     enum { value = I };
 };
 
+} // namespace boost
+
 int main()
 {
     int const x1 = 1;