replace mapping with serializable in compiler

[kostya]

No description provided.

[RX14]

Most of these are structs - can some of the properties be getters instead?

[kostya]

travis crashed with getters:

in src/compiler/crystal/tools/expand.cr:122: undefined method 'expansions=' for Crystal::ExpandResult
        res.expansions = @found_nodes.map { |node| ExpandResult::Expansion.build(node) }

[straight-shoota]

Just use getters where no setters are needed. You don't have to wait for travis if you run the specs locally.

[kostya]

i don't know how it used and where, with mapping it all was as property.

[straight-shoota]

Well, it's just six ivars and you already know one needs a setter. Just trial and error will get you through very quickly.

[asterite]

But what's the problem? They were properties before. I'd say that can be "fixed" in another PR...

[sdogruyol]

Thank you @kostya 👍

[asterite]

Next we should remove mapping.