https://godbolt.org/z/YMMdaq3MM

See for yourself. Here is the code if the godbolt link does not work:
```cpp

#include <print>

class foo {
int actual_value_;
public:
int const& value_ref = actual_value_;
foo(int i) : actual_value_(i) {}

void set_value(int i) {
    actual_value_ = i;
}
};

int main() {
    auto main_foo = foo(1);
    auto foo_copy = main_foo;
    foo_copy.set_value(2);
    std::print("And foo_copy should have value 2 and has '{}'\n",
foo_copy.value_ref);
}
``` . Spoiler alert, it prints 1.. Even worse if you return a foo from a
function in which you may have a dangling reference (if you ain't "lucky"
and RVO saves you... which just hides the problem for a while). // Robin

On Mon, Dec 16, 2024 at 11:33 AM Oskars Putans <o.putaans_at_[hidden]> wrote:

> I'm fairly certain this copies and moves don't break the reference as it
> always references the local variable, not the other variable. Because both
> the member and the reference have the same lifetime, it shouldn't under any
> circumstances be dangling.
>
> Can you provide an example where this does break?
>
>
> On Mon, 16 Dec 2024, 12:23 Robin Savonen Söderholm, <
> robinsavonensoderholm_at_[hidden]> wrote:
>
>> First I have to apologize, I misunderstood the feature... You mean that
>> you want to have something like the getter/setter decorators used in Python?
>>
>> Secondary, the ref thing is broken because it would be wrong or even
>> dangling reference the moment Foo is copied/moved.
>>
>> // Robin
>>
>> On Mon, Dec 16, 2024, 11:11 Oskars Putans via Std-Proposals <
>> std-proposals_at_[hidden]> wrote:
>>
>>> What if you used
>>>
>>> class Foo {
>>> private:
>>> int value;
>>> public:
>>> const int& readOnlyValue = value;
>>> };
>>>
>>> as a way of exposing a const version?
>>>
>>> It might not work in all use cases as it does remove
>>> std::is_trivially_assignable trait from
>>> the class, but this gets rid of an explicit getter and reduces
>>> boilerplate. If you want to support assignment, you need to write your own
>>> overloads. This method is slightly shady, however, as other developers
>>> might make
>>> the assumption that this value won't change. I would rather use getters
>>> for this, but this is one alternative you can consider. Realistically, as a
>>> proposal to core cpp, there's a very low likelihood that this would make
>>> the cut.
>>> --
>>> Std-Proposals mailing list
>>> Std-Proposals_at_[hidden]
>>> https://lists.isocpp.org/mailman/listinfo.cgi/std-proposals
>>>
>>