Function sum_type_variants 

pub fn sum_type_variants(
    name: &str,
    doc_text: &str,
    files: Option<&HashMap<PathBuf, String>>,
) -> Vec<Completion>

v0.124 (slice 3): the variants of a project (or embedded-surface) sum type named name, as pattern completions — the is/match candidate set once the scrutinee’s type is known (resolved handler-side from expr_types). pub so the completion handler can offer them at an is position.

Finding #62: stops at the first unit declaring name, for the same buffer-vs-stale-disk-copy reason as record_field_names above.