Interaction of 'first class spans' with inline array types/Extension methods over inline array types

[InlineArray(40)]
public struct ByteArray40 {
    private byte _b;
}
[InlineArray(20)]
public struct ByteArray20 {
    private byte _b;
}
// many, many others

public static class Extensions {
    public static string decode_name(this Span<byte> name) {
        // ...
    }
}

public struct CHRDATA {
    public ByteArray20 chr_name;
    public ByteArray40 chr_name_extended;

    public void test() {
        string str_chr_name          = chr_name.decode_name();
        string str_chr_name_extended = chr_name_extended.decode_name(); 
    }
}