[Bug c++/67851] New: improve "no unique final overrider" error

["manu at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67851

            Bug ID: 67851
           Summary: improve "no unique final overrider" error
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: manu at gcc dot gnu.org
  Target Milestone: ---

Taken from
http://stackoverflow.com/questions/24006199/virtual-inheritance-error-no-unique-final-overrider

cc1plus:

test.cc:29:7: error: no unique final overrider for âvirtual void base::fun()â
in âder3â
 class der3 : public der1,public der2
       ^

clang++:

38 : error: virtual function 'base::fun' has more than one final overrider in
'der3'
14 : note: overridden virtual function is here
23 : note: final overrider of 'base::fun' in 'der1'
32 : note: final overrider of 'base::fun' in 'der2'


It would be useful if GCC also mentioned which ones are the overriders. In a
complex codebase it could be difficult to figure it out.