Fix casts to void*

include/pybind11/cast.h

@@ -1179,11 +1179,9 @@ enable_if_t<cast_is_temporary_value_reference<T>::value, T> cast_safe(object &&)
     pybind11_fail("Internal error: cast_safe fallback invoked");
 }
 template <typename T>
-enable_if_t<std::is_same<void, intrinsic_t<T>>::value, void> cast_safe(object &&) {}
+enable_if_t<std::is_same<void, T>::value, void> cast_safe(object &&) {}
 template <typename T>
-enable_if_t<detail::none_of<cast_is_temporary_value_reference<T>,
-                            std::is_same<void, intrinsic_t<T>>>::value,
-            T>
+enable_if_t<detail::none_of<cast_is_temporary_value_reference<T>, std::is_same<void, T>>::value, T>
 cast_safe(object &&o) {
     return pybind11::cast<T>(std::move(o));
 }

tests/test_class.cpp

@@ -384,6 +384,7 @@ TEST_SUBMODULE(class_, m) {
 
     protected:
         virtual int foo() const { return value; }
+        virtual void *void_foo() { return (void *) &value; }
 
     private:
         int value = 42;
@@ -392,6 +393,7 @@ TEST_SUBMODULE(class_, m) {
     class TrampolineB : public ProtectedB {
     public:
         int foo() const override { PYBIND11_OVERRIDE(int, ProtectedB, foo, ); }
+        void *void_foo() override { PYBIND11_OVERRIDE(void *, ProtectedB, void_foo, ); }
     };
 
     class PublicistB : public ProtectedB {
@@ -401,11 +403,18 @@ TEST_SUBMODULE(class_, m) {
         // (in Debug builds only, tested with icpc (ICC) 2021.1 Beta 20200827)
         ~PublicistB() override{}; // NOLINT(modernize-use-equals-default)
         using ProtectedB::foo;
+        using ProtectedB::void_foo;
     };
 
+    m.def("read_foo", [](const void *original) {
+        const int *ptr = reinterpret_cast<const int *>(original);
+        return *ptr;
+    });
+
     py::class_<ProtectedB, TrampolineB>(m, "ProtectedB")
         .def(py::init<>())
-        .def("foo", &PublicistB::foo);
+        .def("foo", &PublicistB::foo)
+        .def("void_foo", &PublicistB::void_foo);
 
     // test_brace_initialization
     struct BraceInitialization {

tests/test_class.py

@@ -1,3 +1,5 @@
+import ctypes
+
 import pytest
 
 import env  # noqa: F401
@@ -313,6 +315,7 @@ def test_bind_protected_functions():
 
     b = m.ProtectedB()
     assert b.foo() == 42
+    assert m.read_foo(b.void_foo()) == 42
 
     class C(m.ProtectedB):
         def __init__(self):