With recursive you can easily make (indirectly) recursive functions without worrying about stack overflows by marking them as #[recursive]:

use recursive::recursive;

#[recursive]
fn sum(nums: &[u64]) -> u64 {
    if let Some((head, tail)) = nums.split_first() {
        head + sum(tail)
    } else {
        0
    }
}

Functions marked with #[recursive] will automatically grow the stack size if it is too small when called. See the crate docs for details.

recursive is licensed under the MIT license.