reflection on embedded structs

The ‘transparency’ you expected is just syntactic sugar and has nothing to do with the data representation. If you want to have a function that flattens your data structure, you would have to write it by yourself.

For example (On play):

func DeepFields(iface interface{}) []reflect.Value {
    fields := make([]reflect.Value, 0)
    ifv := reflect.ValueOf(iface)
    ift := reflect.TypeOf(iface)

    for i := 0; i < ift.NumField(); i++ {
        v := ifv.Field(i)

        switch v.Kind() {
        case reflect.Struct:
            fields = append(fields, DeepFields(v.Interface())...)
        default:
            fields = append(fields, v)
        }
    }

    return fields
}