Type checking analysis pass

[nblei]

Dalance,

I would like to add a type checking pass which has a primary goal of evaluating the size (in bits) and packedness of each datatype.

The way I see this working is that a graph whose nodes are types, and whose edges represent dependencies.

For example,

type k = logic<2>;
struct m {
  a: k,
}

Would contain three nodes and two edges: (logic<2>) -> (k) -> (m).

In addition to allowing us to identify the packed size of m, this also allows us to do dependency analysis. The type-graph should be a DAG. If a cycle exists, we have a problem. However, currently

package p {
    struct m {
        a: logic,
        n: n,
    }
    struct n {
        b: logic,
        m: m,
    }
}

passes on this mutually recurssive, but not inductive package p.

Any thoughts on this approach?