What is the meaning of the planned “private protected” C# access modifier?

Question

As part of the Roslyn documentation on GitHub, there\'s a page called Language feature implementation status, with planned language features for C# and VB.

One featu

Answer 1

According to "Professional C# 2008" by De Bill Evjen and Jay Glynn, page 1699:

private protected - "only derived types within the current assembly"

C++/CLI has a similar feature - Define and Consume Classes and Structs (C++/CLI) > Member visibility:

private protected -or- protected private - Member is protected inside the assembly but private outside the assembly.