[Bug c++/19808] New: miss a warning about uninitialized members in constructor

[adl at gnu dot org]

I just ran into bogus code similar to the following.  
(The code is bogus, not GCC, but I believe GCC could have helped.)

// main.cc
#include <iostream>

struct A
{
  A(int x) : x(x) {};
  int call_me() { return x; }
  int x;
};

struct B
{
  B(A* a) : i(the_a->call_me()), the_a(a) {}
  int i;
  A* the_a;
};

int
main()
{
  A a(20);
  B b(&a);
  std::cout << b.i << std::endl;
}

% g++ -O2 -Wall main.cc
% ./a.out
1328900

This displays 1328900 (or any other value) instead of 20 because
the_a->call_me() is invoked before the_a is initialized in 
B's constructor.

It would be useful if g++ could diagnose such use of uninitialized
members in constructors, just like it does for local variables.

-- 
           Summary: miss a warning about uninitialized members in
                    constructor
           Product: gcc
           Version: 3.4.4
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: adl at gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19808