[smart_holder]: trampoline_self_life_support -fvisibility question

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Problem description

I'm attempting to use the Progressive mode to solve a lifetime issue with a trampoline class via the following steps:

1. Added -DPYBIND11_USE_SMART_HOLDER_AS_DEFAULT to compilation commands
2. Replaced std::shared_ptr<...> holder with PYBIND11_SH_DEF(Foo)
3. Inherit trampoline class from public py::trampoline_self_life_support

When I compile, I get this warning:

warning: ‘PyFoo’ declared with greater visibility than its base ‘pybind11::trampoline_self_life_support’ [-Wattributes]
  134 | class PyFoo : Foo, py::trampoline_self_life_support {

Reproducible example code

// C++
#include <pybind11/pybind11.h>

class Foo {
public:
	virtual ~Foo()                   = default;
};


// Trampoline class
class PyFoo : Foo, public py::trampoline_self_life_support {
public:
	using Foo::Foo;
};

// Bindings
PYBIND11_MODULE("smart_holder", m) {
	py::class_<Foo, PyFoo, PYBIND11_SH_DEF(Foo)>(m, "Foo")
		.def(py::init<>())
}