[Bug c++/65415] New: using, base class static member function template, and decltype

[Bug c++/65415] New: using, base class static member function template, and decltype

[rs2740 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65415

            Bug ID: 65415
           Summary: using, base class static member function template, and
                    decltype
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rs2740 at gmail dot com

>From http://stackoverflow.com/questions/29013260.

Minimized repro:

struct default_check
{ 
  template<typename U> static int check(...);
};

struct is_addable : default_check
{
  using default_check::check; // #1
  using type = decltype(check<void>(0));
};

int main() {}

gcc HEAD 5.0.0 20150312 (experimental) reports

prog.cc:9:31: error: expected primary-expression before 'void'
  using type = decltype(check<void>(0));
                              ^
prog.cc:9:31: error: expected ')' before 'void'
prog.cc:9:16: error: expected type-specifier before 'decltype'
  using type = decltype(check<void>(0));
               ^

i.e., for some reason the `check` brought in by `using` isn't found. Oddly
enough, commenting out line #1 makes the code compile.

(The original code in the linked SO question had a separate check() overload in
is_addable. In that case, lookup for some reason only found the is_addable
overload and not the base class one brought in by `using`)

[Bug c++/65415] using, base class static member function template, and decltype

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65415

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-03-13
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Confirmed. EDG and Clang both accept it.

[Bug c++/65415] using, base class static member function template, and decltype

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65415

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mpolacek at gcc dot gnu.org

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Trunk accepts the code since r221478.

[Bug c++/65415] using, base class static member function template, and decltype

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65415

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Closing as Dup. We may want to add the testcase, though, it's slightly
different.

*** This bug has been marked as a duplicate of bug 65061 ***