Fix #227

ecmascript/transforms/src/compat/es2015/parameters/mod.rs

@@ -66,7 +66,10 @@ impl Params {
                     let len_ident = quote_ident!(span.apply_mark(mark), "_len");
 
                     let arg = match *arg {
-                        Pat::Ident(ident) => ident,
+                        Pat::Ident(ident) => {
+                            params.push(Pat::Ident(ident.clone()));
+                            ident
+                        }
                         arg => {
                             let tmp_ident = quote_ident!(span.apply_mark(mark), "_tmp");
                             decls_after_unpack.push(VarDeclarator {

ecmascript/transforms/src/compat/es2015/parameters/tests.rs

@@ -10,6 +10,23 @@ fn tr() -> impl Fold<Module> {
     )
 }
 
+test!(
+    ::swc_ecma_parser::Syntax::default(),
+    |_| tr(),
+    issue_227,
+    "export default function fn1(...args) {
+  fn2(...args);
+}",
+    "
+export default function fn1(args) {
+    for(var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++){
+        args[_key] = arguments[_key];
+    }
+    fn2(...args);
+}
+"
+);
+
 test!(
     ::swc_ecma_parser::Syntax::default(),
     |_| tr(),