[Bug c++/102468] New: False acceptance of invalid `using Parent::Grandparent`

[Bug c++/102468] New: False acceptance of invalid `using Parent::Grandparent`

[fchelnokov at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102468

            Bug ID: 102468
           Summary: False acceptance of invalid `using
                    Parent::Grandparent`
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fchelnokov at gmail dot com
  Target Milestone: ---

This code is invalid due-to specific `using` line, but GCC erroneously accepts
it:
```
struct A {};
struct B : A {};
struct C : B { 
    using B::A;  //???
};
```
There shall be an error printed (as MSVC does)

[Bug c++/102468] False acceptance of invalid `using Parent::Grandparent`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102468

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=62240,
                   |                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=11764,
                   |                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=56090

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is not a GCC bug but rather a bug in MSVC. Note both ICC and Clang accept
it.

Parent::Grandparent names the type, not the constructor.  This is unlike
name::name.

See DR 147 also:
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#147

I think MSVC does not inject the base class name correctly.