fix corner case in `rests` (#4576)

fixes #4575

1 files changed, 5 insertions, 5 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 4710b69f..fc1bc118 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -7845,11 +7845,11 @@ merge(Compressor.prototype, {
         if (fn.rest) {
             if (!(is_iife && compressor.option("rests"))) return;
             var insert = fn.argnames.length;
-            for (var i = args.length; i < insert; i++) {
-                args[i] = make_node(AST_Undefined, call).optimize(compressor);
-            }
-            args[insert] = make_node(AST_Array, call, { elements: args.splice(insert) });
-            fn.argnames.push(fn.rest);
+            args = args.slice(0, insert);
+            while (args.length < insert) args.push(make_node(AST_Undefined, call).optimize(compressor));
+            args.push(make_node(AST_Array, call, { elements: call.args.slice(insert) }));
+            call.args = args;
+            fn.argnames = fn.argnames.concat(fn.rest);
             fn.rest = null;
         }
         var pos = 0, last = 0;