[Bug c++/82560] [7/8 Regression] Temporary object created as a default argument not destructed

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82560

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
      Known to work|                            |6.4.0
           Keywords|                            |wrong-code
   Last reconfirmed|                            |2017-10-16
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=49372
     Ever confirmed|0                           |1
            Summary|Temporary object created as |[7/8 Regression] Temporary
                   |a default argument not      |object created as a default
                   |destructed                  |argument not destructed
   Target Milestone|---                         |7.3
      Known to fail|                            |7.2.0, 8.0

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Confirmed:

extern "C" int printf(const char*, ...);

struct Foo {
  Foo(const char *) {
    printf("%p\tFoo(const char*)\n", this);
  }
  Foo(const Foo&) {
    printf("%p\tFoo(const Foo&)\n", this);
  }
  ~Foo() {
    printf("%p\t~Foo()\n", this);
  }
};

struct Bar {
  Bar(Foo foo = "implicitly casted to Foo") : foo_(foo) {
    printf("%p\tBar(Foo)\n", this);
  }
  ~Bar() {
    printf("%p\t~Bar()\n", this);
  }

  Foo foo_;
};

template<typename T>
struct unique_ptr
{
  unique_ptr(T* p) : p(p) { }
  ~unique_ptr() { delete p; }
  T* p;
};

int main()
{
  {
    printf("OK:\n");
    unique_ptr<Bar> p1(new Bar);
  }
  {
    printf("Wrong:\n");
    unique_ptr<Bar> p2(new Bar());
  }
}