diff --git a/dag/edge.go b/dag/edge.go
index c425d5e5d..f0d99ee3a 100644
--- a/dag/edge.go
+++ b/dag/edge.go
@@ -9,7 +9,7 @@ type Edge interface {
 	Source() Vertex
 	Target() Vertex
 
-	hashable
+	Hashable
 }
 
 // BasicEdge returns an Edge implementation that simply tracks the source
diff --git a/dag/set.go b/dag/set.go
index 8e9f3c410..2b1d7f21b 100644
--- a/dag/set.go
+++ b/dag/set.go
@@ -10,10 +10,10 @@ type Set struct {
 	once sync.Once
 }
 
-// hashable is the interface used by set to get the hash code of a value.
+// Hashable is the interface used by set to get the hash code of a value.
 // If this isn't given, then the value of the item being added to the set
 // itself is used as the comparison value.
-type hashable interface {
+type Hashable interface {
 	Hashcode() interface{}
 }
 
@@ -60,7 +60,7 @@ func (s *Set) List() []interface{} {
 }
 
 func (s *Set) code(v interface{}) interface{} {
-	if h, ok := v.(hashable); ok {
+	if h, ok := v.(Hashable); ok {
 		return h.Hashcode()
 	}