From c28bbb05573dee4d7cbda5f4c654b1fd373c87c4 Mon Sep 17 00:00:00 2001
From: Guy Bedford <guybedford@gmail.com>
Date: Mon, 13 May 2019 03:29:24 +0200
Subject: [PATCH] bootstrap: unfreeze console, document fix cases

---
 doc/api/cli.md                    | 38 +++++++++++++++++++++++++++----
 lib/internal/freeze_intrinsics.js |  2 --
 2 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/doc/api/cli.md b/doc/api/cli.md
index a8a18620fb3152..6a8d9fc2bb5696 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -211,11 +211,41 @@ Support is currently only provided for the root context and no guarantees are
 currently provided that `global.Array` is indeed the default intrinsic
 reference.
 
-**Code breakage is highly likely with this flag**, especially since limited
-support for subclassing builtins is provided currently due to ECMA-262 bug
-https://github.com/tc39/ecma262/pull/1320.
+**Code breakage is highly likely with this flag**, since redefining any
+builtin properties on a subclass will throw in strict mode due to the ECMA-262
+issue https://github.com/tc39/ecma262/pull/1307. This flag may still change
+or be removed in future.
+
+To avoid these cases any builtin function overrides should be defined upfront:
+
+<!-- eslint-disable no-redeclare -->
+```js
+const o = {};
+// THROWS: Cannot assign read only property 'toString' of object
+o.toString = () => 'string';
+
+// OK
+const o = { toString: () => 'string' };
+
+class X {
+  constructor() {
+    this.toString = () => 'string';
+  }
+}
+// THROWS: Cannot assign read only property 'toString' of object
+new X();
+
+class X {
+  toString = undefined;
+  constructor() {
+    this.toString = () => 'string';
+  }
+}
+// OK
+new X();
+```
+
 
-Both of the above may change in future updates, which will be breaking changes.
 
 ### `--heapsnapshot-signal=signal`
 <!-- YAML
diff --git a/lib/internal/freeze_intrinsics.js b/lib/internal/freeze_intrinsics.js
index 753fb00acbccf9..2e6c602706afe4 100644
--- a/lib/internal/freeze_intrinsics.js
+++ b/lib/internal/freeze_intrinsics.js
@@ -32,7 +32,6 @@ module.exports = function() {
     setInterval,
     setTimeout
   } = require('timers');
-  const console = require('internal/console/global');
 
   const intrinsics = [
     // Anonymous Intrinsics
@@ -136,7 +135,6 @@ module.exports = function() {
     setImmediate,
     setInterval,
     setTimeout,
-    console,
 
     // Other APIs
     BigInt,