Address of an overloaded template method as a function call argument

[igor-anferov]

The following piece of code doesn't compile with Clang (21.1.0) while compiling well with GCC (15.2) (see here):

struct S {
    template <class...>
    void f() const& {}
    template <class...>
    void f() & {}
    template <class...>
    void f() && {}
};

template <class R, class Class>
void g(R(Class::*property)() const&) {}

template <class R, class Class>
void g(R(Class::*property)() const) {}

int main() {
    g(&S::f);
}

I think Clang either skips entirely or does poor job at the "template argument deduction" stage of function selection

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Igor Anferov (igor-anferov)

The following piece of code doesn't compile with Clang (21.1.0) while compiling well with GCC (15.2) ([see here](https://compiler-explorer.com/z/qncsqbjdr)): ```c++ struct S { template <class...> void f() const& {} template <class...> void f() & {} template <class...> void f() && {} };

template <class R, class Class>
void g(R(Class::*property)() const&) {}

template <class R, class Class>
void g(R(Class::*property)() const) {}

int main() {
g(&S::f);
}

I think Clang either skips entirely or does poor job at the "template argument deduction" stage of [function selection](https://en.cppreference.com/w/cpp/language/overloaded_address.html#Selecting_functions)
</details>

[keinflue]

I think Clang is correct here. Per [temp.deduct.call]p6.1 the function argument is a non-deduced context because the overload set includes templates.

MSVC and EDG seem to agree: https://compiler-explorer.com/z/WcEd3xGM5