diff --git a/prototype/Doubt/Tree.swift b/prototype/Doubt/Tree.swift
index b13ad5b4d..878bee0ac 100644
--- a/prototype/Doubt/Tree.swift
+++ b/prototype/Doubt/Tree.swift
@@ -1,6 +1,6 @@
 //  Copyright © 2015 GitHub. All rights reserved.
 
-enum Tree<A> {
+public enum Tree<A> {
 	case Leaf(A)
 	case Branch([Tree])
 }