[Bug c++/19968] New: Warning omitted for non-derived classes

[Bug c++/19968] New: Warning omitted for non-derived classes

[reichelt at gcc dot gnu dot org]

Compiling the following code snippet with -Wextra, a sensible warning
is issued:

======================
struct B {};

struct A : B
{
    const int i;
};
======================

warn.cc:5: warning: non-static const member 'const int A::i' in class without a
constructor

However, if A is not a derived class, the warning is not given:

======================
struct A
{
    const int i;
};
======================

This is at least inconsistent. I'd vote for a warning in the second case, too.

-- 
           Summary: Warning omitted for non-derived classes
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: diagnostic, monitored
          Severity: enhancement
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: reichelt at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19968

[Bug c++/19968] [3.3/3.4/4.0 Regression] Warning omitted for non-derived classes

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-02-15 01:32 -------
: Search converges between 2002-10-02-trunk (#92) and 2002-10-03-trunk (#93).

Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|enhancement                 |minor
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-02-15 01:32:08
               date|                            |
            Summary|Warning omitted for non-    |[3.3/3.4/4.0 Regression]
                   |derived classes             |Warning omitted for non-
                   |                            |derived classes
   Target Milestone|---                         |3.4.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19968

[Bug c++/19968] Warning omitted for non-derived classes

[reichelt at gcc dot gnu dot org]

------- Additional Comments From reichelt at gcc dot gnu dot org  2005-02-15 01:29 -------
Btw, the warning in the second case is missing since gcc 3.3.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19968

[Bug c++/19968] [3.3/3.4/4.0/4.1 Regression] Warning omitted for non-derived classes

[aoliva at gcc dot gnu dot org]

------- Additional Comments From aoliva at gcc dot gnu dot org  2005-03-02 21:36 -------
I think this is correct behavior.  Without inheritance, the struct is POD, so
different rules apply.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19968

[Bug c++/19968] [3.3/3.4/4.0/4.1 Regression] Warning omitted for non-derived classes

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2005-03-02 21:54 -------
Correct. The class without inheritance doesn't need a constructor 
since objects of this type can be initialized using a brace-enclosed 
list. The class with inheritance is not POD, so it can't be initialized 
that way and needs a constructor. This should demonstrate this: 
----------------- 
struct B {}; 
 
struct A1 : B { const int i; }; 
struct A2     { const int i; }; 
 
A1 a1 = { 1 }; // not ok 
A2 a2 = { 1 }; // ok 
----------------- 
g/x> /home/bangerth/bin/gcc-3.4.4-pre/bin/c++ -W -Wall -ansi -pedantic -c x.cc 
x.cc:3: warning: non-static const member `const int A1::i' in class without a 
constructor 
x.cc:6: error: `a1' must be initialized by constructor, not by `{...}' 
 
This is therefore not a bug but correct behavior. 
 
W. 

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19968