Returning Set for Reactor.errors does not allow getting errors in order and is bad for practical reporting

[mcfriend99]

Hi,

Thanks for the wonderful library. However, I noticed that the Reactor.errors() method return a Set<SemanticError>. This is bad for practical use as the java Set does not make any guarantee for order in sets. Using a List object might be a better idea because for practical usage, it's really bad when a compiler chunks out errors in an unpredictable order.

Take the Java semantic analyzer for example, it prints semantic errors in order. This will be difficult to achieve using Set<SemanticError>.

[norswap]

Hey there Richard, thanks for the kind words! It's been a while so I don't exactly remember why this was a set, and unfortunately I don't really have time to deal with it at the moment, maybe in a month or two.

However, we could use LinkedHashSet from the standard library which guarantees iteration in insertion order. If you want to make a PR to make that change, I'll approve it :)

Are you using or planning to use Uranium for something? If so, eager to hear about it!