✅ C# 14 extension indexers?

There are extension properties and extension statics, but is it possible to write extension indexers?
I've tried the following, but it says "

this

this

member is not allowed in an extension block".

extension(DataGridViewRow row)
{
    public DataGridViewCell this[int i] => row.Cells[i];
}

extension(DataGridViewRow row)
{
    public DataGridViewCell this[int i] => row.Cells[i];
}