Function registry_resolution_matches 

fn registry_resolution_matches<'a>(
    dependency_keys: &[CanonicalResolutionKey],
    candidates: &'a ProjectResolutionRegistry,
    staged_entities: &'a BTreeMap<String, GraphEntity>,
    control: &IndexWorkControl,
) -> Result<ResolutionMatches<'a>, CliError>

Merge sorted candidate streams without materializing their full union.