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From: "david at doublewise dot net" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/97388] constexpr evaluator incorrectly claims double delete
 with function parameter
Date: Mon, 12 Oct 2020 18:09:39 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97388

--- Comment #2 from David Stone <david at doublewise dot net> ---
That is what seems to be happening here. It looks like by-value function
parameters have all modifications rolled back before the object is destroye=
d.
The following code is also erroneously rejected:

```
struct S {
        int m;

        constexpr S():
                m(1)
        {
        }
        constexpr ~S() noexcept(false) {
                if (m =3D=3D 1) {
                        throw;
                }
        }
};

constexpr bool test(S v) {
        v.m =3D 2;
        return true;
}

static_assert(test(S()));
```

See it live: https://godbolt.org/z/qMjEfo=