Bug#506331: g++-4.3: Misleading warning claims to ignore spurious qualifiers on return type

[Edward Welbourne <eddy@opera.com>]

Package: g++-4.3
Version: 4.3.2-1
Severity: minor

Put the following ridiculous code in a .cpp file: <text>

struct Base { virtual const int stupid() = 0; };
struct Derived : public Base { virtual int stupid() { return 1; } };

</text> and run the compiler on it, with warnings.  I get: <quote>

$ g++ -O2 -Wall -Wextra -o spurious.o -c spurious.cpp
spurious.cpp:1: warning: type qualifiers ignored on function return type
spurious.cpp:2: error: conflicting return type specified for 'virtual int Derived::stupid()'
spurious.cpp:1: error:   overriding 'virtual const int Base::stupid()'
make: *** [spurious.o] Error 1

</quote>

Observe that the warning claims to ignore the spurious const.
However, the error reveals that it was not ignored.
Had it been ignored, the over-ride's return would have matched.

The warning should say
warning: spurious type qualifiers on function return type
or something similar: it should not claim to ignore the type qualifier.

The obvious fix is, of course, to fix the base class: however, if that
is in a library not under my control, this isn't a practical option
when I come to sub-class it.  I am consequently obliged to duplicate
the spurious type qualifier and, hence, get even more warnings about
it :-(

Priority is negligible, of course.

-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (500, 'testing'), (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 2.6.26-1-686 (SMP w/2 CPU cores)
Locale: LANG=en_GB.ISO-8859-15, LC_CTYPE=en_GB.ISO-8859-15 (charmap=ISO-8859-15)
Shell: /bin/sh linked to /bin/bash

Versions of packages g++-4.3 depends on:
ii  gcc-4.3                   4.3.2-1        The GNU C compiler
ii  gcc-4.3-base              4.3.2-1        The GNU Compiler Collection (base 
ii  libc6                     2.7-16         GNU C Library: Shared libraries
ii  libgmp3c2                 2:4.2.2+dfsg-3 Multiprecision arithmetic library
ii  libmpfr1ldbl              2.3.1.dfsg.1-2 multiple precision floating-point 
ii  libstdc++6-4.3-dev        4.3.2-1        The GNU Standard C++ Library v3 (d

g++-4.3 recommends no packages.

Versions of packages g++-4.3 suggests:
pn  g++-4.3-multilib             <none>      (no description available)
ii  gcc-4.3-doc                  4.3.2.nf1-1 documentation for the GNU compiler
pn  libstdc++6-4.3-dbg           <none>      (no description available)

-- no debconf information