Re: c++/9410: [3.4 regression] inability to access a base classes' member from a templated derived class

Re: c++/9410: [3.4 regression] inability to access a base classes' member from a templated derived class

[bangerth]

Synopsis: [3.4 regression] inability to access a base classes' member from a templated derived class

State-Changed-From-To: open->closed
State-Changed-By: bangerth
State-Changed-When: Thu Jan 23 00:25:35 2003
State-Changed-Why:
    That's indeed a complexity of C++. A lone identifier (like "a"), that is not obviously template dependent, will be looked
    up at the time the compiler sees the class, not at instantiation
    time. However, at that point, no information about base
    classes is available yet, so it will not find members of
    the base class.
    
    Regards
      Wolfgang

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=9410

c++/9410: [3.4 regression] inability to access a base classes' member from a templated derived class

[andrew]

>Number:         9410
>Category:       c++
>Synopsis:       [3.4 regression] inability to access a base classes' member from a templated derived class
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 22 23:06:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Andrew Pollard
>Release:        gcc-3.4-20030122
>Organization:
>Environment:
i686-pc-linux-gnu on RedHat8.0/PIII
>Description:
The following snippet of code no longer compiles.

I'm fairly certain it should compile (but I'm not a language laywer).

Previous versions of gcc compile it (including gcc-3.4-20030116)

hidden.cxx:
-----------
struct A {
    int a;
};

template<typename T>
struct B : public A {
};

template<typename T>
struct C : public B<T> {
    int foo() { return (a); }
    int bar() { return (this->a); }
};
----------

% g++34 hidden.cxx -c
hidden.cxx: In member function `int C<T>::foo()':
hidden.cxx:11: error: `a' has not been declared

Note how the use with (this->a) works. From a language point of view I would have expected both to work or both to fail.

Is this a bug, or just another inability of mine to understand the complexity of templates in C++?
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: