test/SILGen/Inputs/private_import_module.swift - third_party/swift - Git at Google

 private protocol HasDefaultFoo {}

 extension HasDefaultFoo {
   private func foo() {}
 }

 private class Base {
   func foo() {}
 }
	private protocol HasDefaultFoo {}

	extension HasDefaultFoo {
	private func foo() {}
	}

	private class Base {
	func foo() {}
	}