[17.4] File Local types

[BillWagner]

C# 11 will add "file local types".

Permit a file modifier on top-level type declarations. The type only exists in the file where it is declared.

• Feature issue: File-local types csharplang#6011
• Proposal specification

This will require changes in the language reference to add the new access modifier. Look at the fundamentals section to consider if the file access modifier should be added there.

[BillWagner]

@Youssef1313 Is there an F1 tag for the file keyword?