Update changelog and test function for GitHub #81 ("Vector with custom allocator does not support value types with operator&")

doc/container.qbk

@@ -1254,6 +1254,7 @@ use [*Boost.Container]? There are several reasons for that:
 * Fixed bugs:
    * [@https://github.com/boostorg/container/issues/77 GitHub #77: ['"warning: 'sbrk' is deprecated"]].
    * [@https://github.com/boostorg/container/issues/79 GitHub #79: ['"Mark small_vector move operations noexcept"]].
+   * [@https://github.com/boostorg/container/issues/81 GitHub #81: ['"Vector with custom allocator does not support value types with operator&"]].
    * [@https://github.com/boostorg/container/issues/82 GitHub #82: ['"Function definition in header file"]].
    * [@https://github.com/boostorg/container/issues/83 GitHub #83: ['"Iterator zero incrementing leads to assert on empty vector"]].
    * [@https://github.com/boostorg/container/pull/84   GitHub #84: ['"Allow vector to be assigned to itself"]].

test/vector_test.cpp

@@ -56,6 +56,29 @@ int test_expand_bwd()
    return 0;
 }
 
+struct X;
+
+template<typename T>
+struct XRef
+{
+   explicit XRef(T* ptr) noexcept : ptr(ptr) {}
+   operator T*() const noexcept { return ptr; }
+   T* ptr;
+};
+
+struct X
+{
+   XRef<X const> operator&() const noexcept { return XRef<X const>(this); }
+   XRef<X>       operator&()       noexcept { return XRef<X>(this); }
+};
+
+
+bool test_smart_ref_type()
+{
+   boost::container::vector<X> x(5);
+   return x.empty();
+}
+
 class recursive_vector
 {
    public:
@@ -184,6 +207,9 @@ int main()
       v.push_back(Test());
    }
 
+   if (test_smart_ref_type())
+      return 1;
+
    ////////////////////////////////////
    //    Backwards expansion test
    ////////////////////////////////////