diff --git a/pmap.go b/pmap.go
index e318f45..9f7183d 100644
--- a/pmap.go
+++ b/pmap.go
@@ -67,7 +67,7 @@ func (p pmap) Len() int {
 func (p pmap) Get(k Key) (Value, bool) {
 	var zero Value
 	h := p.hash(k)
-	return lookup(p.root, 0, h, k, zero)
+	return lookup(p.root, h, k, zero)
 }
 
 func (p pmap) Set(k Key, v Value) Map {
@@ -112,7 +112,8 @@ func (n collision) getNode(hash uint32, key Key) interface{} {
 	return nil
 }
 
-func lookup(root interface{}, shift, hash uint32, key Key, zero Value) (Value, bool) {
+func lookup(root interface{}, hash uint32, key Key, zero Value) (Value, bool) {
+	shift := 0
 	cur := root
 	for {
 		switch n := cur.(type) {