From 5f78c1707afe468aed5aa0912254f9c25310bf35 Mon Sep 17 00:00:00 2001
From: r32 <56782055@qq.com>
Date: Mon, 7 Jul 2025 00:57:18 +0800
Subject: [PATCH] Allow overriding the default generation of rest arguments in
 js-es <= 5

---
 src/generators/genjs.ml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/generators/genjs.ml b/src/generators/genjs.ml
index 3ba99abeae3..eb3528652f1 100644
--- a/src/generators/genjs.ml
+++ b/src/generators/genjs.ml
@@ -757,14 +757,16 @@ and gen_function ?(keyword="function") ctx f pos =
 			else begin
 				check_var_declaration v;
 				let non_rest_args = List.rev args_rev in
-				let args_decl = declare_rest_args_legacy ctx.com (List.length non_rest_args) v in
-				let body =
+				let body = if has_var_flag v VUsedByTyper then
+					let args_decl = declare_rest_args_legacy ctx.com (List.length non_rest_args) v in
 					let el =
 						match f.tf_expr.eexpr with
 						| TBlock el -> args_decl @ el
 						| _ -> args_decl @ [f.tf_expr]
 					in
 					mk (TBlock el) f.tf_expr.etype f.tf_expr.epos
+				else
+					f.tf_expr
 				in
 				{ f with tf_args = non_rest_args; tf_expr = body }, mk_non_rest_arg_names non_rest_args
 			end