uncommenting & adjusting additional test; adding back original code with #if #else #endif

rwgk · rwgk · commit 86299e375127 · 2020-11-30T17:23:29.000-08:00
diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
@@ -960,6 +960,11 @@ template <typename type> class type_caster<std::reference_wrapper<type>> {
 private:
     using caster_t = make_caster<type>;
     caster_t subcaster;
+#if 1
+    using subcaster_cast_op_type = typename caster_t::template cast_op_type<type>;
+    static_assert(std::is_same<typename std::remove_const<type>::type &, subcaster_cast_op_type>::value,
+            "std::reference_wrapper<T> caster requires T to have a caster with an `T &` operator");
+#else
     using reference_t = typename std::add_lvalue_reference<type>::type;
     using subcaster_cast_op_type =
         typename caster_t::template cast_op_type<reference_t>;
@@ -969,6 +974,7 @@ template <typename type> class type_caster<std::reference_wrapper<type>> {
                 std::is_same<reference_t, subcaster_cast_op_type>::value),
                "std::reference_wrapper<T> caster requires T to have a caster "
                "with an `T &` operator or `const T&` operator");
+#endif
 public:
     bool load(handle src, bool convert) { return subcaster.load(src, convert); }
     static constexpr auto name = caster_t::name;
diff --git a/tests/test_builtin_casters.py b/tests/test_builtin_casters.py
@@ -327,8 +327,8 @@ def test_reference_wrapper():
 
     assert m.refwrap_lvalue_const().value == 1
     # const-ness is not propagated.
-    # m.refwrap_lvalue_const().value =2
-    # assert m.refwrap_lvalue_const().value == 1
+    m.refwrap_lvalue_const().value = 2
+    assert m.refwrap_lvalue_const().value == 2
 
     assert m.refwrap_lvalue().value == 1
     m.refwrap_lvalue().value = 4
