py::overload_cast does not work in the presence of a templated function with the same name

[crisluengo]

It seems that py::overload_cast works fine to find bar() in the example below, distinguishing it from bar(int), but cannot find baz(). The only difference is that there is a templated function baz<T>(T).

#include <pybind11/pybind11.h>

class foo {
public:
   void bar();
   void bar( int t );
   void baz();
   template<typename T> void baz( T t );
};

PYBIND11_MODULE( example, m ) {
   auto f = py::class_< foo >( m, "foo" );
   f.def( "bar", py::overload_cast<>( &foo::bar ));  # Finds `void bar()`
   f.def( "baz", py::overload_cast<>( &foo::baz ));  # Fails to find `void baz()`
}

This is the compiler's (Clang) error message:

example.cpp:140:18: error: no matching function for call to object of type 'const detail::overload_cast_impl<>'
   f.def( "baz", py::overload_cast<>( &foo::baz ));
                 ^~~~~~~~~~~~~~~~~~~
/src/pybind11/include/pybind11/detail/common.h:1126:20: note: candidate template ignored: couldn't infer template argument 'Return'
    constexpr auto operator()(Return (*pf)(Args...)) const noexcept -> decltype(pf) {
                   ^
/src/pybind11/include/pybind11/detail/common.h:1131:20: note: candidate template ignored: couldn't infer template argument 'Return'
    constexpr auto operator()(Return (Class::*pmf)(Args...),
                   ^
/src/pybind11/include/pybind11/detail/common.h:1137:20: note: candidate function template not viable: requires 2 arguments, but 1 was provided
    constexpr auto operator()(Return (Class::*pmf)(Args...) const,
                   ^

Using

   f.def( "baz", static_cast< void ( foo::* )() >( &foo::baz ));

does work correctly, so I do have a workaround. But code that calls baz() compiles just fine, I fail to understand why the template resolution fails to infer template argument Return in this case. What am I missing? Or is something that should be fixed in Pybind11?

I think this is related to the question at #4736.