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

 public protocol HasDefaultFoo {}
 extension HasDefaultFoo {
   internal func foo() {}
 }

 internal class Base {
   func foo() {}
 }
	public protocol HasDefaultFoo {}
	extension HasDefaultFoo {
	internal func foo() {}
	}

	internal class Base {
	func foo() {}
	}