The sed is needed because try is now a reserved keyword in Rust 2018.
I don't think we can possibly upgrade to 2021 right now.
Also, I have changed from HashSet to BTreeSet for the expected tokens, because hash set is by definition unordered! And most people may get confused on why the expected token position may change all the time for identical input, because Rust hash map also have further hash randomization to prevent HashDoS attack.
The sed is needed because try is now a reserved keyword in Rust 2018.
I don't think we can possibly upgrade to 2021 right now.
Also, I have changed from HashSet to BTreeSet for the expected tokens, because hash set is by definition unordered! And most people may get confused on why the expected token position may change all the time for identical input, because Rust hash map also have further hash randomization to prevent HashDoS attack.