Closure-level inline constants

[sojuz151]

I propose to add closure-level inline constants. For example the following code

let closeure_uuid = Uuid::new_v4();
let lambda = ||  {
println!("Execution UUID {}",Uuid::new_v4());
println!("Closure UUID {}",closeure_uuid);
};
lambda ();
lambda ();

It could be rewritten as

let lambda = ||  {
println!("Execution UUID {}",Uuid::new_v4());
println!("Closure UUID {}",cc{Uuid::new_v4())});
};
lambda ();
lambda ();

with a new cc keyword similar to constant. This would have similar advantages as inline_const rust-lang/rust#104087. Use cases:

Finer control on what is getting moved inside the lambda. For example

cc{very_larnge_vector.iter().min()}

or

cc{struct.field.other_filed}

More ergonomic dealing with ref counting. Example:

cc{button.clone()}.enable();

Those expressions should be executed when the closure is created and dropped when the closure is dropped.

[workingjubilee]

I don't understand the proposal tbh, is this just an abbreviated syntax for const {}?

[kennytm]

this is like one of the capturing alternatives proposed in #3680 (comment).

as explained in #3680 (comment) it is very hard to grasp the scope/lifetime of the cc {}'ed expression for newcomers.

[workingjubilee]

ah, I see. thank you.