diff --git a/test/helpers/equivalent.hpp b/test/helpers/equivalent.hpp
index f452c807..127a394b 100644
--- a/test/helpers/equivalent.hpp
+++ b/test/helpers/equivalent.hpp
@@ -43,19 +43,15 @@ namespace test
 
     struct equivalent_type {
         template <class T1, class T2>
-        bool operator()(T1 const& x, T2 const& y) {
+        bool operator()(T1 const& x, T2 const& y) const {
             return equivalent_impl(x, y, derived);
         }
     };
 
-    // This won't be a problem as I'm only using a single compile unit
+    // This should't be a problem as I'm only using a single compile unit
     // in each test (this is actually require by the minimal test
     // framework).
-    // 
-    // boostinspect:nounnamed
-    namespace {
-        equivalent_type equivalent;
-    }
+    const equivalent_type equivalent;
 
     template <class Container>
     class unordered_equivalence_tester