BCE0019 'vertices is not a member of 'Mesh' , 'normals' is not a member of 'Mesh'

Trying to use the Mesh class - running through some demo snippets, straight from that linked document.. But, even a copy and paste gets me errors like:

BCE0019 'vertices is not a member of 'Mesh' , 'normals' is not a member of 'Mesh'

The snippet from the doc is copy and pasted below:

function Update () {
    var mesh : Mesh = GetComponent(MeshFilter).mesh;
    var vertices : Vector3[] = mesh.vertices;
    var normals : Vector3[] = mesh.normals;

    for (var i = 0; i < vertices.Length; i++)
        vertices += normals _* Mathf.Sin(Time.time);_
 _*mesh.vertices = vertices;*_
_*}*_
_*
*_

Your script is called Mesh. Rename it to something else so that Unity doesn't get confused about what you mean when you use "Mesh" in the script.