diff --git a/lib/ast.js b/lib/ast.js
index 18053895..5af060d7 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -605,7 +605,7 @@ var AST_Seq = DEFNODE("Seq", "car cdr", {
     },
     $from_array: function(array) {
         if (array.length == 0) return null;
-        if (array.length == 1) return array[0];
+        if (array.length == 1) return array[0].clone();
         var i = array.length - 1;
         var list = array[i];
         while (--i >= 0) {