[Bug c++/81812] [7/8 Regression] Empty virtual function fails to compile

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81812

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-08-11
      Known to work|                            |6.4.0
            Summary|Empty virtual function      |[7/8 Regression] Empty
                   |fails to compile            |virtual function fails to
                   |                            |compile
     Ever confirmed|0                           |1
      Known to fail|                            |7.1.1, 8.0

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Confirmed. Reduced (define FIX to fix the failure):

struct Error {
  virtual void error(... ) const;
};

struct ChildNode : virtual Error {
  void error(... ) const;
};

void ext(const char*, ...);

void ChildNode::error(...) const
{
#ifdef FIX
  ext("");
#endif
}

b.cc:16:1: error: generic thunk code fails for method ‘virtual void
ChildNode::_ZTv0_n24_NK9ChildNode5errorEz(...) const’ which uses ‘...’
 }
 ^