From c09f63aefb4609bbdae259213e7fa458d959e20b Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 9 Aug 2021 01:59:33 +0100
Subject: [PATCH] fix corner case in `rests` (#5109)

fixes #5108
---
 lib/compress.js        |  6 ++++--
 test/compress/rests.js | 22 ++++++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index c19091d7..3820a3ad 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -12313,8 +12313,10 @@ merge(Compressor.prototype, {
 
     OPT(AST_DestructuredArray, function(self, compressor) {
         if (compressor.option("rests") && self.rest instanceof AST_DestructuredArray) {
-            self.elements = self.elements.concat(self.rest.elements);
-            self.rest = self.rest.rest;
+            return make_node(AST_DestructuredArray, self, {
+                elements: self.elements.concat(self.rest.elements),
+                rest: self.rest.rest,
+            });
         }
         return self;
     });
diff --git a/test/compress/rests.js b/test/compress/rests.js
index 45d8e222..a62e380a 100644
--- a/test/compress/rests.js
+++ b/test/compress/rests.js
@@ -1069,3 +1069,25 @@ issue_5100_2: {
     expect_stdout: "PASS"
     node_version: ">=10"
 }
+
+issue_5108: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        rests: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        console.log(function([ ...[ a ] ]) {
+            return a;
+        }([ "PASS", "FAIL" ]));
+    }
+    expect: {
+        console.log(function([]) {
+            return "PASS";
+        }([ "PASS", "FAIL" ]));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}