Object is not destructed while stack-unwinding

[DKay7]

I was solving cpp-quiz and got question with followed code:

#include <iostream>
#include <stdexcept>

struct A {
    A(char c) : c_(c) {}
    ~A() { std::cout << c_; }
    char c_;
};

struct Y { ~Y() noexcept(false) { throw std::runtime_error(""); } };

A f() {
    try {
        A a('a');
        Y y;
        A b('b');
        return {'c'};
    } catch (...) {
    }
    return {'d'};
}

int main()
{
    f();
}

According to standard, program's output should be bcad. But clang-18 produces just bad. I performed some tests and found out that A-object with 'c' value was never destructed. Order of construction and destruction that I get is:

a CONSTRUCTED
b CONSTRUCTED
c CONSTRUCTED
b DESTRUCTED
a DESTRUCTED
d CONSTRUCTED
d DESTRUCTED

[Endilll]

Confirmed: https://godbolt.org/z/Eo9hzjPhe
I feel like that it's not the first filed bug about (lack of) destruction of temporaries during unwinding, but I can't find other issues.

[llvmbot]

@llvm/issue-subscribers-c-1

I was solving cpp-quiz and got [question](https://cppquiz.org/quiz/question/323?result=OK&answer=bcad&did_answer=Answer) with followed code:

#include <iostream>
#include <stdexcept>

struct A {
    A(char c) : c_(c) {}
    ~A() { std::cout << c_; }
    char c_;
};

struct Y { ~Y() noexcept(false) { throw std::runtime_error(""); } };

A f() {
    try {
        A a('a');
        Y y;
        A b('b');
        return {'c'};
    } catch (...) {
    }
    return {'d'};
}

int main()
{
    f();
}

According to standard, program's output should be bcad. But clang-18 produces just bad. I performed some tests and found out that A-object with 'c' value was never destructed. Order of construction and destruction that I get is:

a CONSTRUCTED
b CONSTRUCTED
c CONSTRUCTED
b DESTRUCTED
a DESTRUCTED
d CONSTRUCTED
d DESTRUCTED

[shafik]

Useful to note this example comes from except.ctor p2.

I don't know where we would need to fix this but I am hoping @zygoloid does

NB: I think the last lifetimes issue I saw was: #65282

[zygoloid]

Duplicate of #12658

[llvmbot]

@llvm/issue-subscribers-clang-codegen

I was solving cpp-quiz and got [question](https://cppquiz.org/quiz/question/323?result=OK&answer=bcad&did_answer=Answer) with followed code:

#include <iostream>
#include <stdexcept>

struct A {
    A(char c) : c_(c) {}
    ~A() { std::cout << c_; }
    char c_;
};

struct Y { ~Y() noexcept(false) { throw std::runtime_error(""); } };

A f() {
    try {
        A a('a');
        Y y;
        A b('b');
        return {'c'};
    } catch (...) {
    }
    return {'d'};
}

int main()
{
    f();
}

According to standard, program's output should be bcad. But clang-18 produces just bad. I performed some tests and found out that A-object with 'c' value was never destructed. Order of construction and destruction that I get is:

a CONSTRUCTED
b CONSTRUCTED
c CONSTRUCTED
b DESTRUCTED
a DESTRUCTED
d CONSTRUCTED
d DESTRUCTED