From dda5e5f8a5d680328ca1bb287b82b5410e45e575 Mon Sep 17 00:00:00 2001
From: Voltrex <62040526+VoltrexMaster@users.noreply.github.com>
Date: Tue, 1 Jun 2021 21:09:38 +0430
Subject: [PATCH 1/4] util: use missing validators

The `inherits()` method in the `util` lib module is not using validators which others do use.
---
 lib/util.js | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/lib/util.js b/lib/util.js
index a8d9a356480a35..b9e73a466bc368 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -63,6 +63,7 @@ const { debuglog } = require('internal/util/debuglog');
 const {
   validateFunction,
   validateNumber,
+  validateObject,
 } = require('internal/validators');
 const { TextDecoder, TextEncoder } = require('internal/encoding');
 const { isBuffer } = require('buffer').Buffer;
@@ -229,17 +230,10 @@ function log(...args) {
  *     the super constructor lacks a prototype.
  */
 function inherits(ctor, superCtor) {
+  validateFunction(ctor, 'ctor');
+  validateFunction(superCtor, 'superCtor');
+  validateObject(superCtor.prototype, 'superCtor.prototype');
 
-  if (ctor === undefined || ctor === null)
-    throw new ERR_INVALID_ARG_TYPE('ctor', 'Function', ctor);
-
-  if (superCtor === undefined || superCtor === null)
-    throw new ERR_INVALID_ARG_TYPE('superCtor', 'Function', superCtor);
-
-  if (superCtor.prototype === undefined) {
-    throw new ERR_INVALID_ARG_TYPE('superCtor.prototype',
-                                   'Object', superCtor.prototype);
-  }
   ObjectDefineProperty(ctor, 'super_', {
     value: superCtor,
     writable: true,

From 5ed551978b5b6892755d85b19949a542d89eaf8b Mon Sep 17 00:00:00 2001
From: Voltrex <62040526+VoltrexMaster@users.noreply.github.com>
Date: Tue, 1 Jun 2021 21:16:47 +0430
Subject: [PATCH 2/4] fixup! remove unused error constructor

Removed the `ERR_INVALID_ARG_TYPE` constructor which was only used in the `inherits()` method which is replaced now.
---
 lib/util.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/util.js b/lib/util.js
index b9e73a466bc368..7922846fee0426 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -47,7 +47,6 @@ const {
 const {
   codes: {
     ERR_FALSY_VALUE_REJECTION,
-    ERR_INVALID_ARG_TYPE,
     ERR_OUT_OF_RANGE
   },
   errnoException,

From 43c44914c681b0a7c482e2cd2ad7e94096dd33e4 Mon Sep 17 00:00:00 2001
From: Voltrex <62040526+VoltrexMaster@users.noreply.github.com>
Date: Tue, 1 Jun 2021 22:54:48 +0430
Subject: [PATCH 3/4] fixup! pass valid test value

The value must be a function to test the type of the prototype since validators first check if the value is a function.
---
 test/parallel/test-util-inherits.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/test/parallel/test-util-inherits.js b/test/parallel/test-util-inherits.js
index 1729b1734d03db..6ce2b7da98ce71 100644
--- a/test/parallel/test-util-inherits.js
+++ b/test/parallel/test-util-inherits.js
@@ -82,9 +82,15 @@ assert.strictEqual(e.d(), 'd');
 assert.strictEqual(e.e(), 'e');
 assert.strictEqual(e.constructor, E);
 
+function F() {
+  this.test = 'test';
+}
+
+F.prototype = null;
+
 // Should throw with invalid arguments
 assert.throws(() => {
-  inherits(A, {});
+  inherits(A, F);
 }, {
   code: 'ERR_INVALID_ARG_TYPE',
   name: 'TypeError',

From 80b1d810f51cf8643f403d98c03e9d7b0147c4a2 Mon Sep 17 00:00:00 2001
From: Voltrex <62040526+VoltrexMaster@users.noreply.github.com>
Date: Wed, 2 Jun 2021 00:34:53 +0430
Subject: [PATCH 4/4] fixup! prototype test value

The message expects to fail with the value `undefined`, not `null`.
---
 test/parallel/test-util-inherits.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/parallel/test-util-inherits.js b/test/parallel/test-util-inherits.js
index 6ce2b7da98ce71..ac835852fcb326 100644
--- a/test/parallel/test-util-inherits.js
+++ b/test/parallel/test-util-inherits.js
@@ -86,7 +86,7 @@ function F() {
   this.test = 'test';
 }
 
-F.prototype = null;
+F.prototype = undefined;
 
 // Should throw with invalid arguments
 assert.throws(() => {