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From: "xmh970252187 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/98424] New: The point of destroying temporary objects when
 initializing an array
Date: Wed, 23 Dec 2020 03:01:13 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98424

            Bug ID: 98424
           Summary: The point of destroying temporary objects when
                    initializing an array
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: xmh970252187 at gmail dot com
  Target Milestone: ---

#include <iostream>
struct A{
    A(int id):id_(id){}
    ~A(){
      std::cout<<"destroy A with id: "<<id_<<"\n";
    }
    int id_;
};
struct B{
    B(A const&){
       std::cout<<"construct from A\n";
    }
};
int main(){
    B arr[2] =3D {{0},{1}};
}

GCC destroy each temporary object that was bound to the parameter of `B(A
const&)` before initializing the next element.=20=20

The print is https://godbolt.org/z/j9MMqE:=20=20
````
construct from A
destroy A with id: 0
construct from A
destroy A with id: 1
````=20=20
According to
[class.temporary#6.1](https://timsong-cpp.github.io/cppwp/n4659/class.tempo=
rary#6.1).=20

>A temporary object bound to a reference parameter in a function call persi=
sts until the completion of the full-expression containing the call.=20=20

That means all temporary objects should be destroyed after the initializati=
on
for `arr` has completed. Presumably, it is a bug of GCC that when to destroy
these temporary objects=