Exploring csgrs::polygon::Polygon

[winksaville]

I printed out CSG::polygon of a cube using:

fn print_polygons(polygons: &Vec<Polygon<()>>) {
    //println!("polygon: {:?}", polygon);
    for (idx, polygon) in (polygons.iter()).enumerate() {
        println!("polygon {idx}:");
        println!(" vertices count: {}", polygon.vertices.len());
        //println!(" vertices: {:?}", polygon.vertices);
        for (idx, vertex) in (polygon.vertices.iter()).enumerate() {
            println!("  vertex {idx}:");
            println!("     pos: {:?}", vertex.pos);
            println!("     normal: {:?}", vertex.normal);
        }   
        println!(" plane: {:?}", polygon.plane);
    }
}

And I'm surprised to see -0.0 values

polygon 0:
 vertices count: 4
  vertex 0:
     pos: [0.0, 0.0, 0.0]
     normal: [[-0.0, -0.0, -1.0]]
  vertex 1:
     pos: [0.0, 2.397, 0.0]
     normal: [[-0.0, -0.0, -1.0]]
  vertex 2:
     pos: [2.397, 2.397, 0.0]
     normal: [[-0.0, -0.0, -1.0]]
  vertex 3:
     pos: [2.397, 0.0, 0.0]
     normal: [[-0.0, -0.0, -1.0]]
 plane: Plane { normal: [[0.0, 0.0, -1.0]], w: 0.0 }

it turns out on f64 -0.0 == 0.0 so arithmetically it's fine:

    let a = -0.0_f64;
    let b =  0.0_f64;
    println!("{}", a == b); // prints `true`

But it looks weird and I'm wondering why it is happening?