Function can_reach 

pub fn can_reach(
    chunk_min_x: i32,
    chunk_min_z: i32,
    x: f64,
    z: f64,
    current_step: i32,
    total_steps: i32,
    thickness: f32,
) -> bool

Vanilla’s WorldCarver.canReach — prunes carver steps that can’t touch any block in the given chunk (used by cave/canyon tunnel loops before carving an ellipsoid).