Description

Problem

Resolves #7407

Summary

The formatter is pretty complex when it comes to deciding how to format method calls, call chains and lambdas but I think the fix here is the "correct" one. The explanation for this change is a bit on line 642-664 of chunks.rs, then on 674-680.

The code in the issue:

comptime fn generate_compute_note_hash_and_optionally_a_nullifier() -> Quoted {
    let notes = NOTES.entries();
    if notes.len() > 0 {
        for i in 0..notes.len() {
            let (typ, (_, _, _, _)) = notes[i];

            let get_note_type_id = typ.get_trait_impl(NOTE_INTERFACE).unwrap().methods().filter(|m| {
                m.name() == quote { get_note_type_id }
            })[0]
                .as_typed_expr();
        }

        quote {}
    } else {
        quote {}
    }
}

now gets formatted like this:

comptime fn generate_compute_note_hash_and_optionally_a_nullifier() -> Quoted {
    let notes = NOTES.entries();
    if notes.len() > 0 {
        for i in 0..notes.len() {
            let (typ, (_, _, _, _)) = notes[i];

            let get_note_type_id = typ
                .get_trait_impl(NOTE_INTERFACE)
                .unwrap()
                .methods()
                .filter(|m| m.name() == quote { get_note_type_id })[0]
                .as_typed_expr();
        }

        quote {}
    } else {
        quote {}
    }
}

Note how the method call was split into multiple lines. Before this change it would check what's the width of this line:

            let get_note_type_id = typ.get_trait_impl(NOTE_INTERFACE).unwrap().methods().filter(

It's 96, so less than 100, so it would put all of that on one line then proceed to format the lambda. However, there's still "|m| {" in that line... it could be moved to a separate line but it would look strange. So, this PR is changed to take that piece of code into account when determining whether that first part of the call fits into a single line. In this case it doesn't anymore, so the call chain is split into multiple lines.

rustfmt formats the code in the same way (maybe they use a similar logic).

Additional Context

I also added a couple of Display implementations because they are useful when debugging these things.

Documentation

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.