请考虑以下代码。

#include <stdio.h>
using namespace std;

constexpr size_t TOTAL = 2;

class thing
{
private:
    inline static size_t NEXT_ID = 0;
    size_t id;

public:
    thing() : id(NEXT_ID++)
    {
        printf("Thing %zd created.\n", this->id);
    }
    ~thing()
    {
        printf("Thing %zd destroyed.\n", this->id);
    }
};

class container
{
private:
    inline static size_t NEXT_ID = 0;
    size_t id;
    thing* things;

public:
    container() : id(NEXT_ID++)
    {
        this->things = new thing[TOTAL];
        printf("Container %zd created.\n", this->id);
    }
    ~container()
    {
        delete[] this->things;
        printf("Container %zd destroyed.\n", this->id);
    }

    thing& at(size_t idx)    // this is the important method
    {
        return this->things[idx];
    }
};

int main()
{
    container c;
    c.at(0) = thing();   // here is the problem
    return 0;
}

输出是我没想到的。

Thing 0 created.
Thing 1 created.
Container 0 created.
Thing 2 created.
Thing 2 destroyed.
Thing 1 destroyed.
Thing 2 destroyed.
Container 0 destroyed.

我知道东西2是一个临时对象，所以它被破坏了两次。 我有几个问题是关于事物0发生了什么。

• 为什么东西0没有被销毁？
• 是否会发生内存泄漏？
• 我是否必须以某种方式销毁内容0，或者它是否已被成功覆盖？