diff --git a/src/base/flags.hh b/src/base/flags.hh
index 505a1e54fc..8cefd2d339 100644
--- a/src/base/flags.hh
+++ b/src/base/flags.hh
@@ -55,17 +55,6 @@ class Flags
      */
     operator const Type() const { return _flags; }
 
-    /**
-     * @ingroup api_flags
-     */
-    template <typename U>
-    const Flags<T> &
-    operator=(const Flags<U> &flags)
-    {
-        _flags = flags._flags;
-        return *this;
-    }
-
     /**
      * @ingroup api_flags
      */