That is introducing a new variable binding, and strictly more verbose in all cases for no particular benefit. Destructuring was gone over many times; the problem with using it naively is that it's not clear upon first encountering it whether the destructured object or the fields destructured out of it are disposed. Destructuring is supported via DisposableStack in the proposal. This was already litigated to death and you can see the author's response in your links.
> Destructuring was gone over many times; the problem with using it naively is that it's not clear upon first encountering it whether the destructured object or the fields destructured out of it are disposed.
Yes, and this trivially solves that!
for (const { prop1, prop2 } of iterable)
^ ^
Destructuring Iterable
using (const { prop1, prop2 } of disposable)
^ ^
Destructuring Disposable
No ambiguity. Very clear.
> That is introducing a new variable binding
No. const, let, var are variable bindings with rules about scope and mutability.
using adds to that list. And for the life of me I can't remember what it says about mutability.
using-of would keep that set.
> strictly more verbose in all cases for no particular benefit.
See above.
Additional benefit is that the lifetime of the object is more clear, and it's encouraged to be cleaned up more quickly. Rather than buried in a block with 50 lines before and 50 lines after.
> This was already litigated to death and you can see the author's response in your links.
Absolutely. The owners unfortunately decided to move forward with it.
