[Bug c++/12479] New: superfluous colon with -pedantic gives error not present w/o -pedantic (mozilla build failure)

[Bug c++/12479] New: superfluous colon with -pedantic gives error not present w/o -pedantic (mozilla build failure)

[levon at movementarian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479

           Summary: superfluous colon with -pedantic gives error not present
                    w/o -pedantic (mozilla build failure)
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: levon at movementarian dot org
                CC: gcc-bugs at gcc dot gnu dot org

testcase:

[moz@lambent moz]$ cat a.cpp
extern "C" { };
[moz@lambent moz]$ /usr/local/gcc-cvs/bin/g++ -c a.cpp
[moz@lambent moz]$ /usr/local/gcc-cvs/bin/g++ -pedantic -c a.cpp
a.cpp:1: error: extra `;'

This is a regression against earlier gcc versions (gcc-3.2-7 on RH8)

Originally seen building mozilla, where /usr/include/malloc.h has the
superfluous semicolon.

gcc version 3.4 20030925

[Bug c++/12479] superfluous colon with -pedantic gives error not present w/o -pedantic (mozilla build failure)

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-01 17:46 -------
Maybe -pedantic should not warn about system headers but the error message is correct.

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |critical
           Keywords|                            |diagnostic
            Summary|superfluous colon with -    |System header should not
                   |pedantic gives error not    |cause -pedantic to error
                   |present w/o -pedantic       |about "extra `;'"
                   |(mozilla build failure)     |
   Target Milestone|---                         |3.4


------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-01 17:51 -------
I am not the one who is going to make the discussion here but the error message is correct that 
the semicolon is extra (since 3.4 is more compliant this happens).

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[levon at movementarian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From levon at movementarian dot org  2003-10-01 17:58 -------
<movement> um, should -pedantic be causing /errors/ ?
<zwol> no
<zwol> -pedantic is supposed to just enable more warnings

-pedantic is listed as a warning option. What purpose does
-pedantic-errors have if -pedantic introduces new errors ?

Furthermore, if you insist that -pedantic should fail the build,
it seems that there needs to be some fixincludes work, otherwise
GCC 3.4 g++ and -pedantic will be useless on systems as common
as Red Hat Linux 8.0

See also http://bugzilla.mozilla.org/show_bug.cgi?id=218551

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-01 18:01 -------
-pedantic with C++ is different than -pedantic with C, in C++ it adds errors, -pedantic-error is 
really only useful in C.  This has been this way for a long time but will likely stay this way forever.

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[levon at movementarian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From levon at movementarian dot org  2003-10-01 18:06 -------
The manual should clarify this very odd behaviour. Currently :

`-pedantic'
     Issue all the warnings demanded by strict ISO C and ISO C++;
     reject all programs that use forbidden extensions, and some other
     programs that do not follow ISO C and ISO C++.

does not make the behaviour clear; in particular, no such distinction
between C and C++ is made that I could see.

(Please ignore the previous comment about fixincludes - thinko)

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-01 18:09 -------
"reject all programs that use forbidden extensions" see that part, reject means error, in this case it 
is a forbidden extension.

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[levon at movementarian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From levon at movementarian dot org  2003-10-01 18:19 -------
I know what "reject" means. Like I said, this short phrase does not
make clear the surprising behaviour, and no mention is made of difference
between C and C++ that you state.

Additionally, the docs do not make clear if __extension__ is supposed to
work with such warnings-but-actually-errors (it doesn't, unless I'm doing
something wrong).

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[zack at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From zack at gcc dot gnu dot org  2003-10-01 18:31 -------
Both the documentation and the code are in error here.  This has been discussed
at length on the mailing lists. -pedantic is ONLY to enable additional warnings.
Issuing hard errors for extensions is the sole province of -std=c++98 (or =c89,
or anything without "gnu" in the name).

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[gdr at integrable-solutions dot net]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From gdr at integrable-solutions dot net  2003-10-01 18:44 -------
Subject: Re:  System header should not cause -pedantic to error about "extra `;'"

"levon at movementarian dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| The manual should clarify this very odd behaviour. Currently :
| 
| `-pedantic'
|      Issue all the warnings demanded by strict ISO C and ISO C++;
|      reject all programs that use forbidden extensions, and some other
|      programs that do not follow ISO C and ISO C++.
| 
| does not make the behaviour clear; in particular, no such distinction
| between C and C++ is made that I could see.

Probably.  The -pedantic can turn pedwarns into errors.  We've had
that behaviour for ages.

-- Gaby

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[gdr at integrable-solutions dot net]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From gdr at integrable-solutions dot net  2003-10-01 18:46 -------
Subject: Re:  System header should not cause -pedantic to error about "extra `;'"

"zack at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| Both the documentation and the code are in error here.  This has been discussed
| at length on the mailing lists. -pedantic is ONLY to enable
| additional warnings. 

Not in the C++ front-end.  That also has been debated to death.

-- Gaby

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[zack at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From zack at gcc dot gnu dot org  2003-10-01 18:57 -------

| Probably.  The -pedantic can turn pedwarns into errors.  We've had
| that behaviour for ages.

... and it is a (long-standing) bug.  That's only for -pedantic-errors to do.

| Not in the C++ front-end.  That also has been debated to death.

I'm not as familiar with the history there, but surely you agree that options
like -pedantic should do the same thing in all front ends.

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[gdr at integrable-solutions dot net]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From gdr at integrable-solutions dot net  2003-10-01 19:19 -------
Subject: Re:  System header should not cause -pedantic to error about "extra `;'"

"zack at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| | Probably.  The -pedantic can turn pedwarns into errors.  We've had
| | that behaviour for ages.
| 
| ... and it is a (long-standing) bug.  That's only for -pedantic-errors to do.

The last time this has been discussed, my recollection is that the
intended (and actual) behaviour is that -pedantic can turn some
warnings into errors. 

The reason is that by default we may be lenient about some constructs
and/or just warn.  But if -pedantic then we may reject such codes because
of them violating some standard text requirements.  

The latent bug is that the documentation does not reflect that
intended and actual behaviour. 

| | Not in the C++ front-end.  That also has been debated to death.
| 
| I'm not as familiar with the history there, but surely you agree
| that options like -pedantic should do the same thing in all front ends.

I think -pedantic is front-end dependent just like -ansi.

-- Gaby

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[levon at movementarian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From levon at movementarian dot org  2003-10-01 19:46 -------
> by default we may be lenient about some constructs and/or just warn.

I suppose it's "or" here. As far as I know, there is no way to get an
actual warning about this problem in current GCC. That surely can't be
a good thing ?

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[gdr at integrable-solutions dot net]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From gdr at integrable-solutions dot net  2003-10-01 19:53 -------
Subject: Re:  System header should not cause -pedantic to error about "extra `;'"

"levon at movementarian dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| > by default we may be lenient about some constructs and/or just warn.
| 
| I suppose it's "or" here. As far as I know, there is no way to get an
| actual warning about this problem in current GCC. That surely can't be
| a good thing ?

We should probably do something about system headers.

-- Gaby

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[gdr at integrable-solutions dot net]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From gdr at integrable-solutions dot net  2003-10-01 19:55 -------
Subject: Re:  System header should not cause -pedantic to error about "extra `;'"

"levon at movementarian dot org" <gcc-bugzilla@gcc.gnu.org> writes:
| > by default we may be lenient about some constructs and/or just warn.
| 
| I suppose it's "or" here. As far as I know, there is no way to get an
| actual warning about this problem in current GCC. That surely can't be
| a good thing ?

In the testcase you provided, nothing indicates to GCC that it is
processing a system header.  

-- Gaby

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[levon at movementarian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From levon at movementarian dot org  2003-10-02 01:27 -------
The problem was originally with /usr/include/malloc.h. Is that not a system header ?

Anyway, you didn't really answer my question in comment 13, namely whether
you consider it sensible to only allow these two states :

1) no mention at all of the problem
2) error + rejection

which is the current state of CVS HEAD.

[Bug c++/12479] System header should not cause -pedantic to error about "extra `;'"

[gdr at integrable-solutions dot net]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479



------- Additional Comments From gdr at integrable-solutions dot net  2003-10-02 01:59 -------
Subject: Re:  System header should not cause -pedantic to error about "extra `;'"

"levon at movementarian dot org" <gcc-bugzilla@gcc.gnu.org> writes:
| The problem was originally with /usr/include/malloc.h. Is that not a system header ?

I can't tell.  

| Anyway, you didn't really answer my question in comment 13, namely whether
| you consider it sensible to only allow these two states :
| 
| 1) no mention at all of the problem
| 2) error + rejection
| 
| which is the current state of CVS HEAD.

I think that particular construct is harmless enough so that the error
should probably be warning in regular contexts, ignored if
-Wno-sys-headers (or whatever that option is spelled), and an error if
-pedantic (except in system headers unless -Wsys-headers). 

-- Gaby

[Bug c++/12479] [3.4 only] System header should not cause -pedantic to error about "extra `;'"

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2003-11-30 08:36 -------
I am going to agree and maybe send a patch (do not quote me though).

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2003-11-30 08:36:16
               date|                            |
            Summary|System header should not    |[3.4 only] System header
                   |cause -pedantic to error    |should not cause -pedantic
                   |about "extra `;'"           |to error about "extra `;'"


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479

[Bug c++/12479] [3.4 only] System header should not cause -pedantic to error about "extra `;'"

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|critical                    |normal


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479

[Bug c++/12479] [3.4 only] System header should not cause -pedantic to error about "extra `;'"

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2003-12-22 08:18 -------
Zack is correct that G++ mishandles -pedantic.  It's current behavior (with the
additional complication of -fpermissive) is neither necessary nor concistent
with the C front end.  

The current situation is a way of avoiding having to go through and analyze
every "pedwarn" in G++ to decide whether to make it into:

  if (pedantic) pedwarn (...)

or:

  error (...)

At this point, it would probably just make sense to deprecate -fpermissive, and
make all uses of "pedwarn" in the C++ front end that are not guarded by "if
(pedantic)" into "error" calls.

Meanwhile, I will make the particular pedwarn in question conditional on
!in_system_header, which makes sense anyhow.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |mark at codesourcery dot com
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479

[Bug c++/12479] [3.4 only] System header should not cause -pedantic to error about "extra `;'"

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-12-22 19:00 -------
Subject: Bug 12479

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	mmitchel@gcc.gnu.org	2003-12-22 19:00:13

Modified files:
	gcc/cp         : ChangeLog parser.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g++.dg/parse: semicolon1.C semicolon1.h 

Log message:
	PR c++/12479
	* parser.c (cp_parser_declaration_seq_opt): Only issue "extra ;"
	pedwarn when not in a system header.
	
	PR c++/12479
	* g++.dg/parse/semicolon1.C: New test.
	* g++.dg/parse/semicolon1.h: Likewise.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&r1=1.3828&r2=1.3829
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/parser.c.diff?cvsroot=gcc&r1=1.139&r2=1.140
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.3297&r2=1.3298
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/parse/semicolon1.C.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/parse/semicolon1.h.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479

[Bug c++/12479] [3.4 only] System header should not cause -pedantic to error about "extra `;'"

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2003-12-22 19:01 -------
Fixed in GCC 3.4.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12479