Branches give weird error messages

[DasLixou]

fn inner<'src>() -> impl Parser<'src, &'src str, (), extra::Err<Rich<'src, char>>> {
    just("!")
        .then_ignore(choice((
            just("a").contextual().configure(|_cfg, cond| true),
            just("b").contextual().configure(|_cfg, cond| false),
        )))
        .ignored()
}
let p = inner();
let e = p.parse("!");
for e in e.into_errors() {
    println!("ERROR: {e}");
}

results in this:

ERROR: found end of input expected 'a', or something else

The something else doesn't make sense here as the other contextual is disabled.

[zesterer]

Agreed, this shouldn't happen. It happens today because just("b").contextual().configure(|_cfg, cond| false) is a parser in its own right and needs to return some error: and it incorrectly produces SomethingElse right now, when really it should produce a NothingElse, which never gets listed in the output.

I'll try to find time to fix this soon.