Syntactic sugar for unwrap()

[npetrangelo]

I propose to use the ! character to represent unwrap() on Result and Option types, similar to ? being used for Err and None propagation.

So this:

fn foo(bar: Option<Bar>) -> Bar {
    bar.unwrap()
}

becomes this:

fn foo(bar: Option<Bar>) -> Bar {
    bar!
}

Please do not respond with some flavor of "but syntax proposals are always bad" or "this is not strictly necessary." That is categorically unhelpful. Keep your judgements to the proposed syntax itself.

One issue with this could be if the Option or Result is of a function type, and unwrapping it to call it makes it resemble a macro.

Any other thoughts?

[programmerjake]

there have been proposals for exactly this syntax before: https://internals.rust-lang.org/t/unwrap-operator/18306/11

some people brought up concerns that we don't want to encourage just calling unwrap everywhere, so it shouldn't have special syntax.

[kennytm]

One issue with this could be if the Option or Result is of a function type, and unwrapping it to call it makes it resemble a macro.

not just function type.

let vec = Some(vec ! [1, 2, 3]); // what does `!` mean here?
let item = vec ! [0]; // what does `!` mean here?
// let item = vec.unwrap()[0];
dbg!(item);