Re: c++/7775: std::string foo = foo + "b" is erroneously compiled

Re: c++/7775: std::string foo = foo + "b" is erroneously compiled

[Gabriel Dos Reis]

The following reply was made to PR c++/7775; it has been noted by GNATS.

From: Gabriel Dos Reis <gdr@integrable-solutions.net>
To: Peter Schlaile <udbz@rz.uni-karlsruhe.de>
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: c++/7775: std::string foo = foo + "b" is erroneously compiled
Date: 30 Aug 2002 21:31:45 +0200

 Peter Schlaile <udbz@rz.uni-karlsruhe.de> writes:
 
 | Hi!
 | 
 | On 30 Aug 2002, Gabriel Dos Reis wrote:
 | 
 | > udbz@rz.uni-karlsruhe.de writes:
 | >
 | > No, this is not a bug.  Just before "=", the name foo is available for
 | > use.  The bevaviour is undefined, but that doesn't mean the compiler
 | > is bogus.  It is a bug in your program.
 | 
 | I don't mind 
 
 Sure, you should, because you filled this PR as a "accept-illegal".
 And the code wasn't invalid and the compiler was right in accepting
 it.
 
 -- Gaby

Re: c++/7775: std::string foo = foo + "b" is erroneously compiled

[Peter Schlaile]

The following reply was made to PR c++/7775; it has been noted by GNATS.

From: Peter Schlaile <udbz@rz.uni-karlsruhe.de>
To: Gabriel Dos Reis <gdr@integrable-solutions.net>
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: c++/7775: std::string foo = foo + "b" is erroneously compiled
Date: Fri, 30 Aug 2002 20:00:44 +0200 (CEST)

 Hi!
 
 On 30 Aug 2002, Gabriel Dos Reis wrote:
 
 > udbz@rz.uni-karlsruhe.de writes:
 >
 > No, this is not a bug.  Just before "=", the name foo is available for
 > use.  The bevaviour is undefined, but that doesn't mean the compiler
 > is bogus.  It is a bug in your program.
 
 I don't mind if eventually this conforms to the C++ standard (which is
 strange enough, since
 
 string foo(foo + "a");
 
 is an error), but most definitely you should throw a warning!
 
 Regards,
 Peter
 
 ---
 Peter Schlaile  ***  eMail udbz@rz.uni-karlsruhe.de
 
 So Linus, what are we doing tonight?
           The same thing we do every night Tux. Try to take over the world!
 

Re: c++/7775: std::string foo = foo + "b" is erroneously compiled

[Gabriel Dos Reis]

The following reply was made to PR c++/7775; it has been noted by GNATS.

From: Gabriel Dos Reis <gdr@integrable-solutions.net>
To: nathan@gcc.gnu.org
Cc: gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org,
   udbz@rz.uni-karlsruhe.de, gcc-gnats@gcc.gnu.org
Subject: Re: c++/7775: std::string foo = foo + "b" is erroneously compiled
Date: 30 Aug 2002 18:40:07 +0200

 nathan@gcc.gnu.org writes:
 
 | Synopsis: std::string foo = foo + "b" is erroneously compiled
 | 
 | State-Changed-From-To: open->closed
 | State-Changed-By: nathan
 | State-Changed-When: Fri Aug 30 09:07:58 2002
 | State-Changed-Why:
 |     The code is ill-formed. No diagnostic is required.
 
 Well, the code invokes an undefined behaviour, but it is not
 ill-formed.
 
 -- Gaby

Re: c++/7775: std::string foo = foo + "b" is erroneously compiled

[Gabriel Dos Reis]

The following reply was made to PR c++/7775; it has been noted by GNATS.

From: Gabriel Dos Reis <gdr@integrable-solutions.net>
To: udbz@rz.uni-karlsruhe.de
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: c++/7775: std::string foo = foo + "b" is erroneously compiled
Date: 30 Aug 2002 18:37:32 +0200

 udbz@rz.uni-karlsruhe.de writes:
 
 | >Number:         7775
 | >Category:       c++
 | >Synopsis:       std::string foo = foo + "b" is erroneously compiled
 | >Confidential:   no
 | >Severity:       serious
 | >Priority:       medium
 | >Responsible:    unassigned
 | >State:          open
 | >Class:          accepts-illegal
 
 No, this is not a bug.  Just before "=", the name foo is available for
 use.  The bevaviour is undefined, but that doesn't mean the compiler
 is bogus.  It is a bug in your program.
 
 -- Gaby

Re: c++/7775: std::string foo = foo + "b" is erroneously compiled

[nathan]

Synopsis: std::string foo = foo + "b" is erroneously compiled

State-Changed-From-To: open->closed
State-Changed-By: nathan
State-Changed-When: Fri Aug 30 09:07:58 2002
State-Changed-Why:
    The code is ill-formed. No diagnostic is required.
    	string foo = foo + "b";
    is equivalent to
    	string foo (string (foo.operator+ ("b"));
    which calls string::operator+ on foo, before it has been
    constructed

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7775

c++/7775: std::string foo = foo + "b" is erroneously compiled

[udbz]

>Number:         7775
>Category:       c++
>Synopsis:       std::string foo = foo + "b" is erroneously compiled
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          accepts-illegal
>Submitter-Id:   net
>Arrival-Date:   Fri Aug 30 08:56:01 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     udbz@rz.uni-karlsruhe.de
>Release:        gcc-3.0.3
>Organization:
>Environment:

>Description:
GCC is too permissive when it comes to initialization 
with operator=(): It will even generate illegal code
on optimization-level -O3:


#include <iostream.h>
#include <string>

int main()
{
	std::string foo = foo + "b"; 
	std::cout << foo << endl;
}
>How-To-Repeat:

>Fix:

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