[Bug c/14710] New: Warning about useless casts

[Bug c/14710] New: Warning about useless casts

[debian-gcc at lists dot debian dot org]

[forwarded from http://bugs.debian.org/237207]

It would be nice if there was an option to add a warning about
"useless" casts. Although they are not really incorrect, they
might become incorrect/inefficient as the program evolves. Ie;

struct A { int a; };
struct B : A { int b; };
void func(A *a) { ++a; } 

int main(int ac, char **av)
{
    A a;
    B b;

    func((A*)&a); // Useless cast since a already is an A.
    func(static_cast<A*>(&a)); // Just as useless.
    func((A*)&b); // Useless cast since b is a kind of A.
    func(static_cast<A*>(&b)); // Just as useless.

    return 0;
}

-- 
           Summary: Warning about useless casts
           Product: gcc
           Version: 3.3.4
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: debian-gcc at lists dot debian dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14710

[Bug c++/14710] Warning about useless casts

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-24 06:40 -------
Confirmed, but I do not know how useful this is.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |c++
           Keywords|                            |diagnostic


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14710

[Bug c++/14710] Warning about useless casts

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-03-24 16:50 -------
Subject: Re:  Warning about useless casts

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

| Confirmed, but I do not know how useful this is.

Please can you make it an enhancement with low priority?

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14710

[Bug c++/14710] Warning about useless casts

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-24 16:56 -------
Should have confirmed it.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Priority|P2                          |P3
   Last reconfirmed|0000-00-00 00:00:00         |2004-03-24 16:56:18
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14710

[Bug c++/14710] Warning about useless casts

[stl at caltech dot edu]

------- Additional Comments From stl at caltech dot edu  2004-04-02 07:49 -------
I am in favor of this warning, though I don't expect that it would occur often 
(except in C, where programmers incessantly cast the return values of malloc() 
and friends).

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14710