[Bug c++/67767] New: -Wsuggest-attribute=noreturn suggests noreturn for function which already has noreturn and cold.

[zerotype at yahoo dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67767

            Bug ID: 67767
           Summary: -Wsuggest-attribute=noreturn suggests noreturn for
                    function which already has noreturn and cold.
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zerotype at yahoo dot com
  Target Milestone: ---

(Observed in Ubuntu builds of g++ 4.9.2 and 5.1.0)

I have a class containing various function pointers which are initialised
depending on command-line parameters specified by the user. To catch any bugs
which could result in one of the pointers not pointing to a valid function, the
class's constructor normally default-initialises them to point to functions
which throw exceptions - like so:

//header file containing declaration:
> typedef void (*objfunc_entity_specific_assignment_function)	(objective_function_struct& ofs, gmips_entity_specific_information_struct& gesis, const sbox_size_object& sso);
> void entity_specific_assignment_function_not_set		[[gnu::cold, gnu::noreturn]] (objective_function_struct& ofs, gmips_entity_specific_information_struct& gesis, const sbox_size_object& sso);

//cpp file:
> void entity_specific_assignment_function_not_set(objective_function_struct& ofs, gmips_entity_specific_information_struct& gesis, const sbox_size_object& sso)
> {
> 	throw misc_exception(__FILE__" " + std::string(__PRETTY_FUNCTION__) + " called.\n");
> }

Before I added the gnu::cold attribute, compiling with
-Wsuggest-attribute=noreturn did not result in the noreturn attribute being
suggested, because of course the function already had it. After changing from
[[gnu::noreturn]] to [[gnu::cold, gnu::noreturn]] I get:

> warning: function might be candidate for attribute ‘noreturn’ [-Wsuggest-attribute=noreturn]
> void entity_specific_assignment_function_not_set(objective_function_struct& ofs, gmips_entity_specific_information_struct& gesis, const sbox_size_object&
>      ^