Re: c++/3024: class inheritance of template arguments fail

["Artem Khodush" <artem@duma.gov.ru>]

The following reply was made to PR c++/3024; it has been noted by GNATS.

From: "Artem Khodush" <artem@duma.gov.ru>
To: <jorgen.sigvardsson@kau.se>
Cc: <gcc-gnats@gcc.gnu.org>, <gcc-bugs@gcc.gnu.org>
Subject: Re: c++/3024: class inheritance of template arguments fail
Date: Fri, 1 Jun 2001 14:15:30 +0400

 > Classes may not inherit from template argument. I use this with 
 > the Microsoft Visual C++ compiler frequently (ATL uses it heavily). 
 > I don't know if this is C++ by the book, or if it is a Microsoft extension.
 > 
 > The code which fail for me looks like:
 > 
 > template <typename T>
 > class Y : public T
 > {
 > // ...
 > };
 > 
 > class X : public Y<X>
 > {
 > };
 > 
 
 Your code does not compile with Visual C++ 6.0.
 The error message is pretty much the same:
 
 c:\m\t\main.cpp(4) : error C2504: 'X' : base class undefined
  
 This has nothing to do with inheriting from template argument.
 You want to have a class which indirectly inherits from itself,
 this is impossible in C++.