On Wed, Nov 22, 2023 at 11:25 AM Barry Revzin via Std-Proposals
<std-proposals_at_[hidden]> wrote:
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> On Wed, Nov 22, 2023, 9:03 AM Tony V E via Std-Proposals <std-proposals_at_[hidden]> wrote:
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>> I have implemented it.
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>> It just isn't used that much. So no real implementation experience either way. It hasn't been a problem, but neither optional<T&> nor assignment come up that much at all, so inconclusive.
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> Disagree. optional<T&> comes up quite a bit. And we use it a lot. I don't understand where the claim comes from - it's clearly used.
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>> If anything, I'd say
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>> Imagine that vector.front() returns an optional<T&>...
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>> As the developer writing vector, I'd like assignment to rebind.
>> As the developer using vector.front(), I'd like assignment to not rebind.
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>> auto f = vector.front();
>> if (f)
>> f = 17; // current optional would not be able to assign from an rvalue
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>> But again, totally inconclusive.
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> Disagree again. If you want to assign through, there's syntax for that: *f = 17. This is the same thing you would write if front() returned a T* instead. It's the most reasonable choice too - if you want to operate in the T&, you pull out the T& and operate on that. Same as you would for any other type. optional<T&> is an optional, so it behaves like an optional - it's not literally a reference.
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> Muddling the semantics of assignment to save a single character of syntax in this case doesn't seem like a great tradeoff.

So what you're saying is that this is fine:

```
T t = value;
t = other_value; //Assign-through to the object named by `t`.

optional<T> t = value;
t = other_value; //Assign-through to the `T` in `t`.

T &t = object;
t = other_value; //Assign through to the object referenced by `t`.

optional<T&> t = object;
t = other_value; //Not assign-through.
```

This is one of the few places in the language where a language
reference is treated as a distinct concept from the object it is
referencing. References to objects are assign-through. Optional
objects are assign-through. Optional references-to-objects are not
assign-through.

And that's supposed to make sense.