diff --git a/ast/map.go b/ast/map.go
index 3f7c0f4197..28872c4ee3 100644
--- a/ast/map.go
+++ b/ast/map.go
@@ -72,7 +72,7 @@ func (vs *ValueMap) Len() int {
 func (vs *ValueMap) Get(k Value) Value {
 	if vs != nil {
 		if v, ok := vs.hashMap.Get(k); ok {
-			return v.(Value)
+			return v
 		}
 	}
 	return nil
diff --git a/topdown/copypropagation/unionfind.go b/topdown/copypropagation/unionfind.go
index 08b30c51e9..7e6639cb4e 100644
--- a/topdown/copypropagation/unionfind.go
+++ b/topdown/copypropagation/unionfind.go
@@ -94,7 +94,7 @@ func (uf *unionFind) String() string {
 	}
 
 	uf.roots.Iter(func(k ast.Value, v *unionFindRoot) bool {
-		o.Roots[k.(ast.Value).String()] = struct {
+		o.Roots[k.String()] = struct {
 			Constant *ast.Term
 			Key      ast.Value
 		}{