diff --git a/ecmascript/transforms/Cargo.toml b/ecmascript/transforms/Cargo.toml
index 702eeddc198..e76607aec33 100644
--- a/ecmascript/transforms/Cargo.toml
+++ b/ecmascript/transforms/Cargo.toml
@@ -16,6 +16,7 @@ swc_ecma_parser = { path ="../parser" }
 either = "1.5"
 fnv = "1"
 serde = { version = "1", features = ["derive"] }
+objekt = "0.1"
 
 [dev-dependencies]
 testing = { path ="../../testing" }
diff --git a/ecmascript/transforms/src/compat/es2015/arrow/mod.rs b/ecmascript/transforms/src/compat/es2015/arrow/mod.rs
index 703af6810a2..81a0b37708d 100644
--- a/ecmascript/transforms/src/compat/es2015/arrow/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/arrow/mod.rs
@@ -56,7 +56,7 @@ mod tests;
 /// };
 /// console.log(bob.printFriends());
 /// ```
-pub fn arrow() -> impl Pass {
+pub fn arrow() -> impl Pass + Clone + Copy {
     Arrow
 }
 
diff --git a/ecmascript/transforms/src/compat/es2015/block_scoped_fn.rs b/ecmascript/transforms/src/compat/es2015/block_scoped_fn.rs
index 46ecf1590b7..754beaf345e 100644
--- a/ecmascript/transforms/src/compat/es2015/block_scoped_fn.rs
+++ b/ecmascript/transforms/src/compat/es2015/block_scoped_fn.rs
@@ -1,4 +1,3 @@
-use crate::pass::Pass;
 use ast::*;
 use swc_common::{Fold, FoldWith, DUMMY_SP};
 
diff --git a/ecmascript/transforms/src/compat/es2015/classes/mod.rs b/ecmascript/transforms/src/compat/es2015/classes/mod.rs
index 27b6afc49e0..66ee2c30783 100644
--- a/ecmascript/transforms/src/compat/es2015/classes/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/classes/mod.rs
@@ -1,4 +1,4 @@
-use crate::{helpers::Helpers, pass::Pass, util::ExprFactory};
+use crate::{helpers::Helpers, util::ExprFactory};
 use ast::*;
 use std::{
     iter,
diff --git a/ecmascript/transforms/src/compat/es2015/computed_props/mod.rs b/ecmascript/transforms/src/compat/es2015/computed_props/mod.rs
index 56bc43248c0..abfbb0286fe 100644
--- a/ecmascript/transforms/src/compat/es2015/computed_props/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/computed_props/mod.rs
@@ -41,7 +41,7 @@ mod tests;
 ///
 /// TODO(kdy1): cache reference like (_f = f, mutatorMap[_f].get = function(){})
 ///     instead of (mutatorMap[f].get = function(){}
-pub fn computed_properties(helpers: Arc<Helpers>) -> impl Pass {
+pub fn computed_properties(helpers: Arc<Helpers>) -> impl Pass + Clone {
     ComputedProps { helpers }
 }
 
diff --git a/ecmascript/transforms/src/compat/es2015/destructuring/mod.rs b/ecmascript/transforms/src/compat/es2015/destructuring/mod.rs
index bfc3a366c57..1b02ef915c5 100644
--- a/ecmascript/transforms/src/compat/es2015/destructuring/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/destructuring/mod.rs
@@ -35,7 +35,7 @@ mod tests;
 ///     b = _arr2[1],
 ///     rest = _arr2.slice(2);
 /// ```
-pub fn destructuring(helpers: Arc<Helpers>) -> impl Pass {
+pub fn destructuring(helpers: Arc<Helpers>) -> impl Pass + Clone {
     Destructuring { helpers }
 }
 
diff --git a/ecmascript/transforms/src/compat/es2015/duplicate_keys/mod.rs b/ecmascript/transforms/src/compat/es2015/duplicate_keys/mod.rs
index f2d83a5918d..8a97a2ffea4 100644
--- a/ecmascript/transforms/src/compat/es2015/duplicate_keys/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/duplicate_keys/mod.rs
@@ -7,7 +7,7 @@ use swc_common::{Fold, FoldWith, Spanned};
 #[cfg(test)]
 mod tests;
 
-pub fn duplicate_keys() -> impl Pass {
+pub fn duplicate_keys() -> impl Pass + Clone + Copy {
     DuplicateKeys
 }
 
diff --git a/ecmascript/transforms/src/compat/es2015/for_of/mod.rs b/ecmascript/transforms/src/compat/es2015/for_of/mod.rs
index 2cc31ef4822..cba55573bf4 100644
--- a/ecmascript/transforms/src/compat/es2015/for_of/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/for_of/mod.rs
@@ -42,7 +42,7 @@ mod tests;
 ///   }
 /// }
 /// ```
-pub fn for_of() -> impl Pass {
+pub fn for_of() -> impl Pass + Clone + Copy {
     ForOf
 }
 
diff --git a/ecmascript/transforms/src/compat/es2015/function_name/mod.rs b/ecmascript/transforms/src/compat/es2015/function_name/mod.rs
index 1649d6d5927..754038ffdef 100644
--- a/ecmascript/transforms/src/compat/es2015/function_name/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/function_name/mod.rs
@@ -1,4 +1,3 @@
-use crate::pass::Pass;
 use ast::*;
 use swc_common::{Fold, FoldWith};
 
diff --git a/ecmascript/transforms/src/compat/es2015/mod.rs b/ecmascript/transforms/src/compat/es2015/mod.rs
index bab7e6c62d7..557c2f44fd2 100644
--- a/ecmascript/transforms/src/compat/es2015/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/mod.rs
@@ -8,7 +8,6 @@ pub use self::{
 use crate::{helpers::Helpers, pass::Pass};
 use ast::{Expr, Module, Stmt};
 use std::sync::Arc;
-use swc_common::Fold;
 
 mod arrow;
 mod block_scoped_fn;
@@ -28,8 +27,8 @@ mod template_literal;
 mod typeof_symbol;
 
 /// Compiles es2015 to es5.
-pub fn es2015(helpers: &Arc<Helpers>) -> impl Pass {
-    fn exprs(helpers: &Arc<Helpers>) -> impl Pass {
+pub fn es2015(helpers: &Arc<Helpers>) -> impl Pass + Clone {
+    fn exprs(helpers: &Arc<Helpers>) -> impl Pass + Clone {
         chain_at!(
             Expr,
             arrow(),
@@ -51,7 +50,7 @@ pub fn es2015(helpers: &Arc<Helpers>) -> impl Pass {
         )
     }
 
-    fn stmts(helpers: &Arc<Helpers>) -> impl Pass {
+    fn stmts(helpers: &Arc<Helpers>) -> impl Pass + Clone {
         chain_at!(
             Stmt,
             exprs(helpers),
diff --git a/ecmascript/transforms/src/compat/es2015/parameters/mod.rs b/ecmascript/transforms/src/compat/es2015/parameters/mod.rs
index 7e9b3362d6d..1cace77e495 100644
--- a/ecmascript/transforms/src/compat/es2015/parameters/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/parameters/mod.rs
@@ -1,4 +1,4 @@
-use crate::{pass::Pass, util::ExprFactory};
+use crate::util::ExprFactory;
 use ast::*;
 use swc_common::{Fold, FoldWith, Mark, Spanned, DUMMY_SP};
 
diff --git a/ecmascript/transforms/src/compat/es2015/template_literal/mod.rs b/ecmascript/transforms/src/compat/es2015/template_literal/mod.rs
index 8f8d5cdad02..a62185b455d 100644
--- a/ecmascript/transforms/src/compat/es2015/template_literal/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/template_literal/mod.rs
@@ -1,4 +1,4 @@
-use crate::{helpers::Helpers, pass::Pass, util::ExprFactory};
+use crate::{helpers::Helpers, util::ExprFactory};
 use ast::*;
 use std::{
     iter,
diff --git a/ecmascript/transforms/src/compat/es2016/exponentation.rs b/ecmascript/transforms/src/compat/es2016/exponentation.rs
index ee5e25ad4fe..11334e3cb13 100644
--- a/ecmascript/transforms/src/compat/es2016/exponentation.rs
+++ b/ecmascript/transforms/src/compat/es2016/exponentation.rs
@@ -24,7 +24,7 @@ use swc_common::{Fold, FoldWith, Mark, Span, Spanned, Visit, VisitWith, DUMMY_SP
 ///
 /// x = Math.pow(x, 3);
 /// ```
-pub fn exponentation() -> impl Pass {
+pub fn exponentation() -> impl Pass + Clone {
     Exponentation
 }
 #[derive(Clone, Copy)]
diff --git a/ecmascript/transforms/src/compat/es2016/mod.rs b/ecmascript/transforms/src/compat/es2016/mod.rs
index 3ace800028d..78c5f3f857f 100644
--- a/ecmascript/transforms/src/compat/es2016/mod.rs
+++ b/ecmascript/transforms/src/compat/es2016/mod.rs
@@ -1,10 +1,8 @@
 pub use self::exponentation::exponentation;
 use crate::pass::Pass;
-use ast::Module;
-use swc_common::Fold;
 
 mod exponentation;
 
-pub fn es2016() -> impl Pass {
+pub fn es2016() -> impl Pass + Clone {
     exponentation()
 }
diff --git a/ecmascript/transforms/src/compat/es2017/async_to_generator/mod.rs b/ecmascript/transforms/src/compat/es2017/async_to_generator/mod.rs
index 7facc8a8527..800915247b3 100644
--- a/ecmascript/transforms/src/compat/es2017/async_to_generator/mod.rs
+++ b/ecmascript/transforms/src/compat/es2017/async_to_generator/mod.rs
@@ -33,7 +33,7 @@ mod tests;
 ///   yield bar();
 /// });
 /// ```
-pub fn async_to_generator(helpers: Arc<Helpers>) -> impl Pass {
+pub fn async_to_generator(helpers: Arc<Helpers>) -> impl Pass + Clone {
     AsyncToGenerator { helpers }
 }
 
diff --git a/ecmascript/transforms/src/compat/es2017/mod.rs b/ecmascript/transforms/src/compat/es2017/mod.rs
index 70d62b6946d..cc2cd06b8e6 100644
--- a/ecmascript/transforms/src/compat/es2017/mod.rs
+++ b/ecmascript/transforms/src/compat/es2017/mod.rs
@@ -4,6 +4,6 @@ use std::sync::Arc;
 
 mod async_to_generator;
 
-pub fn es2017(helpers: &Arc<Helpers>) -> impl Pass {
+pub fn es2017(helpers: &Arc<Helpers>) -> impl Pass + Clone {
     async_to_generator(helpers.clone())
 }
diff --git a/ecmascript/transforms/src/compat/es2018/object_rest_spread/mod.rs b/ecmascript/transforms/src/compat/es2018/object_rest_spread/mod.rs
index bacca5ba6d5..4d31bf39250 100644
--- a/ecmascript/transforms/src/compat/es2018/object_rest_spread/mod.rs
+++ b/ecmascript/transforms/src/compat/es2018/object_rest_spread/mod.rs
@@ -1,5 +1,6 @@
 use crate::{
     helpers::Helpers,
+    pass::Pass,
     util::{ExprFactory, StmtLike},
 };
 use ast::*;
@@ -15,7 +16,7 @@ use swc_common::{
 mod tests;
 
 /// `@babel/plugin-proposal-object-rest-spread`
-pub fn object_rest_spread(helpers: Arc<Helpers>) -> impl Fold<Module> {
+pub fn object_rest_spread(helpers: Arc<Helpers>) -> impl Pass + Clone {
     chain!(
         ObjectRest {
             helpers: helpers.clone(),
@@ -24,6 +25,7 @@ pub fn object_rest_spread(helpers: Arc<Helpers>) -> impl Fold<Module> {
     )
 }
 
+#[derive(Clone)]
 struct ObjectRest {
     helpers: Arc<Helpers>,
 }
@@ -899,6 +901,7 @@ fn simplify_pat(pat: Pat) -> Pat {
     pat.fold_with(&mut PatSimplifier)
 }
 
+#[derive(Clone)]
 struct ObjectSpread {
     helpers: Arc<Helpers>,
 }
diff --git a/ecmascript/transforms/src/lib.rs b/ecmascript/transforms/src/lib.rs
index a96c259994c..c80506e106f 100644
--- a/ecmascript/transforms/src/lib.rs
+++ b/ecmascript/transforms/src/lib.rs
@@ -31,6 +31,7 @@ extern crate test;
 #[macro_use]
 extern crate testing;
 extern crate either;
+extern crate objekt;
 extern crate serde;
 
 pub use self::{
diff --git a/ecmascript/transforms/src/pass.rs b/ecmascript/transforms/src/pass.rs
index 23ceee1afeb..23a93f7d94c 100644
--- a/ecmascript/transforms/src/pass.rs
+++ b/ecmascript/transforms/src/pass.rs
@@ -15,9 +15,9 @@ macro_rules! mk_impl {
 macro_rules! mk_trait {
     ($($T:ty,)*) => {
         /// Crazy trait to make traversal fast again.
-        pub trait Pass: Clone + $( ::swc_common::Fold<$T> + )* {}
+        pub trait Pass: objekt::Clone + $( ::swc_common::Fold<$T> + )* {}
         impl<P> Pass for P
-            where P: ?Sized + Clone + $( ::swc_common::Fold<$T> +)*{
+            where P: ?Sized + objekt::Clone + $( ::swc_common::Fold<$T> +)*{
 
         }