[Bug c++/84573] missing warning on an uninstantiated function template returning T with no return statement

2021-12-17 Thread msebor at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84573

Martin Sebor  changed:

   What|Removed |Added

 Status|WAITING |NEW

--- Comment #4 from Martin Sebor  ---
I believe the warning would be helpful because as I mentioned in comment #0:

  ...the only valid specialization of such a template is one where T = void
it's likely that the missing return statement is a mistake...

A function template that returns a template argument should be defined that way
even if it's meant to be instantiated on void:

  template 
  T g () { return T (); }   // valid for any default-constructible type, even
void

  void h () { return g(); }   // valid

Warning for a missing return statement would be helpful in template libraries
that rarely instantiate all their code either during a build or in their tests.

[Bug c++/84573] missing warning on an uninstantiated function template returning T with no return statement

2021-12-17 Thread mpolacek at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84573

Marek Polacek  changed:

   What|Removed |Added

 CC||mpolacek at gcc dot gnu.org

--- Comment #3 from Marek Polacek  ---
I personally think we should not add such a warning.

[Bug c++/84573] missing warning on an uninstantiated function template returning T with no return statement

2021-12-16 Thread pinskia at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84573

Andrew Pinski  changed:

   What|Removed |Added

 Status|UNCONFIRMED |WAITING
 Ever confirmed|0   |1
   Last reconfirmed||2021-12-17

--- Comment #2 from Andrew Pinski  ---
Plus this is valid:
template 
T g () { }   // missing warning

template<> void g();


So having a return here would be invalid code and the warning might influence
someone to add it.

What do you think?

[Bug c++/84573] missing warning on an uninstantiated function template returning T with no return statement

2021-12-16 Thread pinskia at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84573

Andrew Pinski  changed:

   What|Removed |Added

   Severity|normal  |enhancement

--- Comment #1 from Andrew Pinski  ---
No compiler (ICC, GCC, MSVC or clang) warns about this and I don't know how
useful it is really.