id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
7114	Destructor not called when using emplace()	Alexandre Hamez <alexandre.hamez@…>	Ion Gaztañaga	"Consider the following source code:
{{{
#include <iostream>
#include <set>

#include <boost/container/flat_set.hpp>

struct foo
{
  int i_;

  foo(int i)
    : i_(i)
  {
    std::cout << ""foo() "" << this << std::endl;
  }

  ~foo()
  {
    std::cout << ""~foo() "" << this << std::endl;
  }

  foo(foo&& other)
    : i_(other.i_)
  {
    std::cout << ""foo(foo&&) "" << this << std::endl;
  }

  foo&
  operator=(foo&& other)
  {
    std::cout << ""foo& operator=(foo&&)"" << this << std::endl;
    i_ = other.i_;
    return *this;
  }

  bool
  operator==(const foo& other)
  const
  {
    return i_ == other.i_;
  }

  bool
  operator<(const foo& other)
  const
  {
    return i_ < other.i_;
  }
};

int
main()
{
  boost::container::flat_set<foo> set;
  // std::set<foo> set;
  std::cout << ""*************"" << std::endl;
  set.emplace(42);
  std::cout << ""*************"" << std::endl;
  set.emplace(42);
  std::cout << ""*************"" << std::endl;
  return 0;
}

}}}

When compiled with clang 3.1 or gcc 4.8 and launched, it displays:

{{{
*************
foo() 0x7fff6bfb29f8
foo(foo&&) 0x10c400900
*************
foo() 0x7fff6bfb29f8
*************
~foo() 0x10c400900
}}}

Three instances are created (two constructors and one move-contructor), but only one destructor is called.
As a side note, when using an {{{std::set}}} (of the libc++) instead of a {{{boost::container::flat_set}}}, it displays:

{{{
*************
foo() 0x10490091c
*************
foo() 0x10490093c
~foo() 0x10490093c
*************
~foo() 0x10490091c
}}}
 "	Bugs	closed	To Be Determined	container	Boost 1.50.0	Problem	fixed