Test and document binding protected member functions

tests/test_class.cpp

@@ -229,6 +229,57 @@ TEST_SUBMODULE(class_, m) {
     // This test is actually part of test_local_bindings (test_duplicate_local), but we need a
     // definition in a different compilation unit within the same module:
     bind_local<LocalExternal, 17>(m, "LocalExternal", py::module_local());
+
+    // test_bind_protected_functions
+    class ProtectedA {
+    protected:
+        int foo() const { return value; }
+
+    private:
+        int value = 42;
+    };
+
+    class PublicistA : public ProtectedA {
+    public:
+        using ProtectedA::foo;
+    };
+
+    py::class_<ProtectedA>(m, "ProtectedA")
+        .def(py::init<>())
+#if !defined(_MSC_VER) || _MSC_VER >= 1910
+        .def("foo", &PublicistA::foo);
+#else
+        .def("foo", static_cast<int (ProtectedA::*)() const>(&PublicistA::foo));
+#endif
+
+    class ProtectedB {
+    public:
+        virtual ~ProtectedB() = default;
+
+    protected:
+        virtual int foo() const { return value; }
+
+    private:
+        int value = 42;
+    };
+
+    class TrampolineB : public ProtectedB {
+    public:
+        int foo() const override { PYBIND11_OVERLOAD(int, ProtectedB, foo, ); }
+    };
+
+    class PublicistB : public ProtectedB {
+    public:
+        using ProtectedB::foo;
+    };
+
+    py::class_<ProtectedB, TrampolineB>(m, "ProtectedB")
+        .def(py::init<>())
+#if !defined(_MSC_VER) || _MSC_VER >= 1910
+        .def("foo", &PublicistB::foo);
+#else
+        .def("foo", static_cast<int (ProtectedB::*)() const>(&PublicistB::foo));
+#endif
 }
 
 template <int N> class BreaksBase { public: virtual ~BreaksBase() = default; };