diff --git a/include/boost/optional.hpp b/include/boost/optional.hpp
index 69317ad..21d52d8 100644
--- a/include/boost/optional.hpp
+++ b/include/boost/optional.hpp
@@ -426,7 +426,7 @@ class optional : public optional_detail::optional_base<T>
     // No-throw (assuming T::~T() doesn't)
     ~optional() {}
 
-#ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
+#if !defined(BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT) && !defined(BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION)
     // Assigns from an expression. See corresponding constructor.
     // Basic Guarantee: If the resolved T ctor throws, this is left UNINITIALIZED
     template<class Expr>