Property cannot be declared public because its type uses an internal type

Question

I created two classes Content and Bucket. Bucket contains an array of Content objects and exposes that via a public property

Answer 1

You have to declare the access level of the Content class public as well.

public class Content {
   // some code
}

As stated in the documentation:

A public variable cannot be defined as having an internal or private type, because the type might not be available everywhere that the public variable is used.

Classes are declared as internal by default, so you have to add the public keyword to make them public.

A similar rule exists for functions as well.

A function cannot have a higher access level than its parameter types and return type, because the function could be used in situations where its constituent types are not available to the surrounding code.