libstdc++/7187: virtual keyword parser error in STL templates

[wls at wwco dot com]

>Number:         7187
>Category:       libstdc++
>Synopsis:       Parse error concerning virtual keyword in the STL template
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 02 12:36:05 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Walt Stoneburner
>Release:        3.1
>Organization:
self
>Environment:
Slackware 8.0
System: Linux spiff 2.4.17 #2 Wed Jan 16 17:37:02 EST 2002 i686 unknown
Architecture: i686

	
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ../configure 
>Description:
Including and using the STL <fstream> used to work in 3.0.x.
GCC v3.1 now produces an error message, even if the file is
included and never called.
In file included from /usr/local/include/g++-v3/fstream:48,
                 from t.cc:1:
/usr/local/include/g++-v3/bits/basic_file.h:52: parse error before `{' token
/usr/local/include/g++-v3/bits/basic_file.h:57: virtual outside class
   declaration
...technically, the STL has this inside of a struct, but even if
you change the STL to read class, it does not work.
	
>How-To-Repeat:
1. Make a C++ file with just the include header.  No code will
   call it.

wls@spiff:/tmp$ cat /tmp/t.cc
#include <fstream>

wls@spiff:/tmp$ g++ -v
Reading specs from /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.1/specs
Configured with: ../configure
Thread model: single
gcc version 3.1


2. Compile the file ... which should fail at the link stage.
   We don't get that far.

wls@spiff:/tmp$ g++ /tmp/t.cc
In file included from /usr/local/include/g++-v3/fstream:48,
                 from /tmp/t.cc:1:
/usr/local/include/g++-v3/bits/basic_file.h:52: parse error before `{' token
/usr/local/include/g++-v3/bits/basic_file.h:57: virtual outside class
   declaration
/usr/local/include/g++-v3/bits/basic_file.h:57: function `int std::overflow(int
   = -1)' is initialized like a variable
hen reporting a compiler error, preprocessor output must be included>
>Fix:
Not using <fstream> causes the error to go away in my projects,
however, I'm then left without a file streaming mechanism.
	
>Release-Note:
>Audit-Trail:
>Unformatted: