[Bug c++/33975] New: [4.1/4.2/4.3 Regression] Incomplete types may be derefenced

[Bug c++/33975] New: [4.1/4.2/4.3 Regression] Incomplete types may be derefenced

[andrew dot stubbs at st dot com]

The following C++ program should not compile:

struct S;
int f(S s);

S *p;
int i = f(*p);

Here an incomplete type is dereferenced as it is passed as a function
argument.

This is forbidden by the C++ standard, clause 3, paragraph 4 (penultimate
bullet). And anyway, how could you compile it to anything sensible without
knowing how big the type is?

Other attempts to dereference incomplete types are diagnosed correctly.

This used to be diagnosed in GCC 4.1.1, but is missing in GCC 4.1.2 onwards.


-- 
           Summary: [4.1/4.2/4.3 Regression] Incomplete types may be
                    derefenced
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: andrew dot stubbs at st dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33975

[Bug c++/33975] [4.1/4.2/4.3 Regression] Incomplete types may be derefenced

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2007-11-02 13:59 -------
Confirmed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |accepts-invalid
   Last reconfirmed|0000-00-00 00:00:00         |2007-11-02 13:59:28
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33975

[Bug c++/33975] [4.1/4.2/4.3 Regression] Incomplete types may be derefenced

[janis at gcc dot gnu dot org]

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------- Comment #2 from janis at gcc dot gnu dot org  2007-11-12 18:01 -------
Mainline now reports an error for this code:

elm3b187% /opt/gcc-nightly/trunk/bin/g++ 33975.cc
33975.cc: In function ‘int main()’:
33975.cc:8: error: invalid use of incomplete type ‘struct S’
33975.cc:1: error: forward declaration of ‘struct S’
33975.cc:8: error:   initializing argument 1 of ‘int f(S)’

The patch that fixed this for mainline:

    http://gcc.gnu.org/viewcvs?view=rev&rev=129968

    r129968 | jakub | 2007-11-07 19:27:27 +0000 (Wed, 07 Nov 2007)

Here's the source file I used:

struct S;
int f(S s);

int
main ()
{
  S *p;
  int i = f(*p);
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33975

[Bug c++/33975] [4.1/4.2/4.3 Regression] Incomplete types may be derefenced

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2007-11-12 19:50 -------
The issue here is an exact dup of bug 33501.

*** This bug has been marked as a duplicate of 33501 ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33975