[Bug c++/85554] New: GCC does not instantiate template function when only used as a function type

[me at adhokshajmishraonline dot in]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85554

            Bug ID: 85554
           Summary: GCC does not instantiate template function when only
                    used as a function type
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: me at adhokshajmishraonline dot in
  Target Milestone: ---

Proof of concept:
=================

template<typename T>
auto make_value(){
    return T{};
}

template<typename F>
auto call(F func){
    return func();
}

int main(){
    auto result = call(make_value<double>);
    return 0;
}


Compiling with G++
==================

╭─ adhokshajmishra@andromeda  in /tmp 
╰─➤  g++ --version                                                              
g++ (GCC) 7.3.1 20180406
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

╭─ adhokshajmishra@andromeda  in /tmp 
╰─➤  g++ test.cpp -o test -std=c++17                                            
test.cpp: In function ‘int main()’:
test.cpp:12:42: error: no matching function for call to ‘call(<unresolved
overloaded function type>)’
     auto result = call(make_value<double>);
                                          ^
test.cpp:7:6: note: candidate: template<class F> auto call(F)
 auto call(F func){
      ^~~~
test.cpp:7:6: note:   template argument deduction/substitution failed:
test.cpp:12:42: note:   couldn't deduce template parameter ‘F’
     auto result = call(make_value<double>);
                                          ^

Compiling with Clang: no error

As per [http://eel.is/c++draft/temp#inst-4.sentence-1], GCC seems to be wrong
here.