compilation error with Clang 3.4

[wojdyr]

What version (or hash if on master) of pybind11 are you using?

2.13.5

Problem description

I suppose Clang 3.4 is not widely used anymore, but just to let you know.
I tried building my bindings on an old system with Clang 3.4 and I got:

include/pybind11/detail/type_caster_base.h:260:9: error: 
      return type 'pybind11::handle' must match previous return type 'const pybind11::handle' when
      lambda expression has unspecified explicit return type
        return handle();
        ^

It's this lambda:

pybind11/include/pybind11/detail/type_caster_base.h

Lines 251 to 261 in 3fb16ad

	return with_instance_map(src, [&](instance_map &instances) {
	auto it_instances = instances.equal_range(src);
	for (auto it_i = it_instances.first; it_i != it_instances.second; ++it_i) {
	for (auto *instance_type : detail::all_type_info(Py_TYPE(it_i->second))) {
	if (instance_type && same_type(*instance_type->cpptype, *tinfo->cpptype)) {
	return handle((PyObject *) it_i->second).inc_ref();
	}
	}
	}
	return handle();
	});

After adding -> handle as the return type, the compiler was satisfied and I didn't come across any other problems.

Is this a regression? Put the last known working version here if it is.

must be a regression, but I don't know what was the last working version