Function origin_metrics 

pub fn origin_metrics(
    families: &[OriginFamily],
    fields: &[FieldDecl],
    scope: &[Scope<'_>],
    cases: &[Option<OriginCase<'_>>],
) -> Vec<NewMetric>

The origin metrics of the declared families, in declaration order; fields are the adapter’s field declarations (3.4.7). Each entry of cases belongs to the same index of scope: some for a proposal, none for a case outside every new metric. A family listed twice, which the configuration check refuses, is reported once.

Panics

If scope and cases differ in length.