[Bug c++/70820] GCC incorrectly accepts code that accesses nested names in an incomplete type

[fdrocha at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70820

Fabio Rocha <fdrocha at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #2 from Fabio Rocha <fdrocha at gmail dot com> ---
(In reply to Jason Merrill from comment #1)
> 14.7.1:  "The implicit instantiation of a class template specialization
> causes the implicit instantiation of the declarations, but not of the
> definitions, default arguments, or exception-specifications of the class
> member functions, member classes, scoped member enumerations, static data
> members and member templates; and it causes the implicit instantiation of
> the definitions of unscoped member enumerations and member anonymous unions."
> 
> So I don't think that the instantiation of Base<Derived> requires the
> instantiation of the definition of Base<Derived>::i.

You may be correct, not sure this is actually bug. 
Still, it feels pretty strange that uncommenting the "First Assert" is what
makes the code incorrect...