From b9d5bba5fb8e70c10f25f56ff6e7228739461cfb Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Sun, 30 May 2021 02:00:48 +0100
Subject: [PATCH] fix corner case in `dead_code` (#4983)

fixes #4982
---
 lib/compress.js          |  2 ++
 test/compress/classes.js | 46 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/lib/compress.js b/lib/compress.js
index 4c967074..7ea1e533 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3646,6 +3646,8 @@ merge(Compressor.prototype, {
         var block;
         stat.walk(new TreeWalker(function(node, descend) {
             if (node instanceof AST_DefClass) {
+                node.extends = null;
+                node.properties = [];
                 push(node);
                 return true;
             }
diff --git a/test/compress/classes.js b/test/compress/classes.js
index bbfea753..cbecf669 100644
--- a/test/compress/classes.js
+++ b/test/compress/classes.js
@@ -1679,3 +1679,49 @@ issue_4962_2: {
     expect_stdout: "undefined"
     node_version: ">=12"
 }
+
+issue_4982_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        "use strict";
+        try {} catch (e) {
+            class A extends 42 {}
+        }
+        console.log("PASS");
+    }
+    expect: {
+        "use strict";
+        {
+            class A {}
+        }
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4982_2: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = "PASS";
+        try {} catch (e) {
+            class A {
+                static p = a = "FAIL";
+            }
+        }
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        {
+            class A {}
+        }
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}