Bug#249691: gcc-3.4: false compiler error (templated base, templated child, private member)

[Jay Berkenbilt <ejb@ql.org>]

Package: gcc-3.4
Version: 3.4.0-2
Severity: important
Tags: experimental

Consider this code fragment:

template <class T>
class A
{
  protected:
    int f;
};

template <class T>
class B: public A<T>
{
  public:
    B()
    {
	f = 1;   // line 14
    }
};

gcc-3.3 has no problem with this, but gcc-3.4 complains as follows:

a.cc: In constructor `B<T>::B()':
a.cc:14: error: `f' undeclared (first use this function)
a.cc:14: error: (Each undeclared identifier is reported only once for each function it appears in.)

Changing f on line 14 to any of this->f, B<T>::f, or A<T>::f works
around the problem.  There is also no problem if either B or A is not
templated.

I am unable to find anything in the C++ specification that indicates
that gcc 3.4's behavior is correct, but it's hard to find things in
the C++ spec!  As far as I know, there are no circumstances under
which fully qualifying a name is required when there is only one
candidate in the scope.  The fact that A and B are both templated does
not change the fact that "f" is a protected member variable of the
parent class.

I have NOT reported this upstream as the only version of gcc-3.4 that
I've tried is the one in experimental.

This bug is related to bug 245368.  If the gcc people agree that this
is a bug, I will merge that bug with this one.  (There someone
reported that xerces23 fails to compile with gcc 3.4.  The compiler
errors were of this nature.)

Gratuitous comment: it's great to see g++ 3.4 in experimental.  It
will be easier for me to test my complex C++ software against it than
ever before.  Thanks. :-)

-- 
Jay Berkenbilt <ejb@ql.org>
http://www.ql.org/q/



-- System Information:
Debian Release: testing/unstable
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)
Kernel: Linux 2.4.26-1-686-smp
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8

Versions of packages gcc-3.4 depends on:
ii  binutils                   2.14.90.0.7-6 The GNU assembler, linker and bina
ii  cpp-3.4                    3.4.0-2       The GNU C preprocessor
ii  gcc-3.4-base               3.4.0-2       The GNU Compiler Collection (base 
ii  libc6                      2.3.2.ds1-12  GNU C Library: Shared libraries an
ii  libgcc1                    1:3.4.0-2     GCC support library

-- no debconf information