Function cargo::ops::cargo_compile::resolve_all_features

pub fn resolve_all_features(
    resolve_with_overrides: &Resolve,
    resolved_features: &ResolvedFeatures,
    package_set: &PackageSet<'_>,
    package_id: PackageId
) -> HashSet<String>

Gets all of the features enabled for a package, plus its dependencies’ features.

Dependencies are added as dep_name/feat_name because required-features wants to support that syntax.