Function evaluate_rust 

pub fn evaluate_rust(
    report: &LlvmCovReport,
    thresholds: RustThresholds,
) -> Outcome

Decide whether report meets both thresholds.

Fails when the run measured no regions at all (an empty denominator — a wrong path, or a crate that compiled nothing — is never a silent pass), otherwise checks regions and lines and fails listing each below its floor.