[Bug c++/69774] New: Corrupted 'this' passed through lambda.

[guille at cal dot berkeley.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69774

            Bug ID: 69774
           Summary: Corrupted 'this' passed through lambda.
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: guille at cal dot berkeley.edu
  Target Milestone: ---

Created attachment 37669
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37669&action=edit
Preprocessed source

The code below compiles+runs fine on gcc 4.7, but fails on gcc version 6.0.0
20151220 (on intel Mac). 
On gcc 4.7 it outputs the same two pointers (say "0x7fff5f896ba0
0x7fff5f896ba0"), while on 6.0.0 it outputs "0x7fff5f896ba0 0x7fff5f896bc0").


#include <thread>
#include <iostream>

struct Thread                                                                  
        : std::thread
{
    Thread() = default;
    template <class F, class... P> Thread(F&& task, P&&... p)
    : std::thread(
         [&task] (P&&... p) { task(std::forward<P> (p)...); }, 
         std::forward<P> (p)...
      )
    {}
    Thread& operator = (Thread&& t)
    {
        (std::thread&)*this = std::move((std::thread&)t);
        return *this;
    }
};

struct A
{
    int a;
    Thread t;

    A()
    {
        t = [this] { std::cerr << &a << " \n"; };
    }
    ~A()
    {
        t.join();
    }
};

int main()
{
    A a;
    std::cerr << &a.a << " \n";
    return 0;
}