The code below (and in Playground)

    let v = vec![3i32, 2i32].iter();
    println!("{}", v.sum::<i32>());

Errors due to a temporary being dropped.

I expected this would convert to something close to (but the last example contradicts it):

let v = {
       let _tmp =vec![3i32, 2i32];
       <[_]>::iter(&_tmp[..])
  }; // underlying data is dropped after we exit block expression

But if that were the case, should happen the same here?

let f = move |a| a;
let v = f(&6);
println!("{v}")

But this runs fine.

So, what rule is being applied in terms of drop scope, in the first case? And in the second?

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