Function split_selectors_by_label_use 

fn split_selectors_by_label_use(
    matches: &[String],
) -> Result<(Vec<String>, Vec<VectorSelector>)>

Splits match[] selectors by whether they constrain an ordinary label. The first group is answerable from table metadata; the second needs the data read and is returned as parsed selectors.

or matchers stay in the metadata group, which ignores them, rather than being silently dropped from a data scan that cannot express them.