Refactor Type::Aggregate

[YerinAlexey]

Description

Aggregate types weren't implemented quite right and caused various problems like Type.size() being broken. Now Type::Aggregate takes a reference to a TypeDef object, which it can use to calculate the size and assert correctness of the generated code because it would be a violation of Rust's rules to have an aggregate without a corresponding definition.

ToDo

• Proposed feature/fix is sufficiently tested
• Proposed feature/fix is sufficiently documented
• The "Unreleased" section in the changelog has been updated, if applicable

[garritfra]

Works like a charm! While trying this out I also wrote one more test, just to get a hang of it:

#[test]
fn type_size_nested_aggregate() {
    let inner = TypeDef {
        name: "dog".into(),
        align: None,
        items: vec![(Type::Long, 2)],
    };
    let inner_aggregate = Type::Aggregate(&inner);

    assert!(inner_aggregate.size() == 16);

    let typedef = TypeDef {
        name: "person".into(),
        align: None,
        items: vec![(Type::Long, 1), (Type::Word, 2), (Type::Byte, 1), (Type::Aggregate(&inner), 1)],
    };
    let aggregate = Type::Aggregate(&typedef);

    assert!(aggregate.size() == 33);
}

I don't think I can push to this branch, as it lives in your fork. Do you mind adding this, alongside the Changelog entry?

[garritfra]

Nevermind, I think I am able to push to your fork. I'll finish this up. Thanks!

[YerinAlexey]

we forgot about alignment

[garritfra]

How would that affect the size? Probably just has to be added to the sum of the size, right?

[YerinAlexey]

How would that affect the size? Probably just has to be added to the sum of the size, right?

Yes, every item in a typedef has to be extended so that it's dividable by the alignment (or by default, non-aligned size of largest item).
And this obviously follows a change to Antimony to emit padding in structs and take alignment into account when doing field access.