Add ErrorCode enum with error codes

[FroMage]

Insted of using numbers and luck all over the code.

[gavinking]

Definitely not for 1.1.5 since that would be a huge breaking change to the contract b/w typechecker and IDE.

[gavinking]

Plus what would be much better would be to create subclasses of AnalysisError, which would also allow transmission of extra info to the IDE. This would be a misuse of enums, since you're talking about a large, open-ended set of options.

[FroMage]

huge breaking change

What? Turning a bunch of ints into enums? That's a big change? It's annoying because it's manual, since you never defined constants instead of literals, but that's a pretty trivial manual change.

Perhaps subclasses of error would work too, but if we're talking about 100 error codes, you will still need enums (which BTW is what it's made for) because you're not going to create 100 subclasses.

[gavinking]

That's a big change?

Sure, it immediately makes the 1.1.5 IDE incompatible with the 1.1.0 compiler and vice-versa.

[FroMage]

Well, not really because they don't talk to eachother since the IDE ships with its own version of the compiler. And that will be true anyways when we add features in the AST like if expressions. So that's a really weak point. Look, if you truely hate having to learn how to declare an enum (I have nailed it, haven't I?) then define some old-fashion static final int ERROR_CODE_X constats at least ;)

These magic numbers are used in at least three projects now so it really looks ridiculous. When these were 2-3 constants it was OK, but now, it just looks bad.