Compiler bug?

[Alexandre Oliva]

On Apr  8, 2003, Nathan Myers <ncm-nospam@cantrip.org> wrote:

>   bug.cc: In instantiation of `Outer<char>::Inner':
>   bug.cc:14:   instantiated from here
>   bug.cc:12: `sizeof' applied to incomplete type `Outer<char>::Inner'

> Outer<>::Inner doesn't look incomplete to me. 

There's no such thing as flexible array members in C++.  An earlier
draft of the C99 Standard said:

       A structure type containing a flexible array member is an
       incomplete type that cannot be completed.  [6.2.5]/23

but this statement is gone from the final version.  This was probably
done to address the incompatibility that would arise between sizeof
being well-defined for structs with flexible array members
[6.7.2.1]/17, and the requirement that the expression given to sizeof
doesn't have an incomplete type [6.5.3.4]/1 (hmm...  how about to the
incomplete type itself?)

For short: looks like a bug to me.  Compliance with (parts of) the
draft but not the final standard.

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                 aoliva@{redhat.com, gcc.gnu.org}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist                Professional serial bug killer