diff --git a/entity/expression.go b/entity/expression.go
index 449a419..3c0e7ce 100644
--- a/entity/expression.go
+++ b/entity/expression.go
@@ -477,8 +477,8 @@ var _ Expression = &For { }
 type For struct {
 	// Syntax
 	Pos     errors.Position
-	Index   Expression
-	Element Expression
+	Index   *Declaration
+	Element *Declaration
 	Over    Expression
 	Body    Expression