diff --git a/prototype/Doubt/Cofree.swift b/prototype/Doubt/Cofree.swift
index 1899932a2..6ec780837 100644
--- a/prototype/Doubt/Cofree.swift
+++ b/prototype/Doubt/Cofree.swift
@@ -1,7 +1,7 @@
 //  Copyright © 2015 GitHub. All rights reserved.
 
 public enum Cofree<A, B> {
-	case Unroll(B, Syntax<Cofree, A>)
+	indirect case Unroll(B, Syntax<Cofree, A>)
 }