[Bug c++/103906] New: Illegal program not detected, ambiguous conversion operator

[Bug c++/103906] New: Illegal program not detected, ambiguous conversion operator

[agulanyan87 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103906

            Bug ID: 103906
           Summary: Illegal program not detected, ambiguous conversion
                    operator
           Product: gcc
           Version: 11.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: agulanyan87 at gmail dot com
  Target Milestone: ---

Created attachment 52121
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52121&action=edit
A complete example of the issue

Please have a look at the file attached.

As you can see the conversion operator to int is ambiguous - both base classes
have the same conversion operator defined. So, I expect any call of this
conversion operator should result in a compilation error.

Unfortunately, gcc does not produce an error on this ambiguous call.

Interestingly, if a named member function is used instead of a conversion
operator, the error is currently detected. This is included in the example file
too.

Tried clang - the error is correctly detected on both member function and
conversion operator calls.

[Bug c++/103906] Illegal program not detected, ambiguous conversion operator

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103906

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-01-04
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
      Known to fail|                            |4.1.2

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, I thought I had saw another bug like this but I can't find it.
Also MSVC accepts the code but uses the base from NewValue rather than what GCC
does which is uses the base from OldValue.