Cannot use lifetimes in return types for `aoc{,_generator}`

[ErichDonGubler]

When one uses a return value with a lifetime in it, #[aoc(...)] panicks with an error similar to:

~/…/personal/advent-of-code-2018 lifetime-problems$ cargo build
   Compiling advent-of-code-2018 v0.1.0 (<snip>)
error[E0261]: use of undeclared lifetime name `'a`
  --> src\day6.rs:47:1
   |
47 | #[aoc(day6, part1)]
   | ^^^^^^^^^^^^^^^^^^^ undeclared lifetime

error: aborting due to previous error

For more information about this error, try `rustc --explain E0261`.
error: Could not compile `advent-of-code-2018`.

To learn more, run the command again with --verbose.

You can check out a fully-reproducible example that the above is based on in the lifetime-problems branch of my AoC2018 solutions. The most interesting file is day6.rs, which I'll inline for posterity since I'll be deleting that branch once this issue is resolved:

use {
    aoc_runner_derive::{
        aoc,
        aoc_generator,
    },
    re_parse::{
        Regex,
        ReParse,
    },
    serde_derive::Deserialize,
    std::str::Split,
};

#[derive(Debug, Deserialize, ReParse)]
#[re_parse(regex = r#"(?P<x>\d{1,10}), (?P<y>\d{1,10})"#)]
struct Coordinate {
    x: u32,
    y: u32,
}

#[derive(Debug)]
struct CoordinateParser<'a> {
    input: Split<'a, char>,
}

impl<'a> CoordinateParser<'a> {
    pub fn new(input: Split<'a, char>) -> Self {
        Self {
            input,
        }
    }
}

impl Iterator for CoordinateParser<'_> {
    type Item = Coordinate;

    fn next(&mut self) -> Option<Self::Item> {
        Some(self.input.next()?.parse().unwrap())
    }
}

#[aoc_generator(day6)]
fn day6_generator<'a>(input: &'a str) -> CoordinateParser<'a> {
    CoordinateParser::new(input.trim().split('\n'))
}

#[aoc(day6, part1)]
pub fn day6_part1(input: CoordinateParser<'_>) -> u32 {
    println!("input: {:#?}", input);
    0
}

[aymericbouzy]

I'm a beginner in rust and I don't feel I'd be able to fix this issue. Is there a recommended workaround? Circumventing the need for a lifetime I expect?

[LemmingAvalanche]

I have no idea how to resolve a similar-looking error. main() it is, then.

[ithinuel]

It does not work with impl Trait as return time either. From what I understand it is because the return type of the generator is used to define a field in the RunnerStruct.

[zaneduffield]

I came across this limitation recently and I opted to simply not use a generator in my solution. This meant simply calling my parsing function from within my solution function.