diff --git a/benchmark/module/load-native.js b/benchmark/module/load-native.js
new file mode 100644
index 00000000000000..b5859a189705f1
--- /dev/null
+++ b/benchmark/module/load-native.js
@@ -0,0 +1,32 @@
+'use strict';
+const path = require('path');
+// Use an absolute path as the old loader was faster using an absolute path.
+const commonPath = path.resolve(__dirname, '../common.js');
+const common = require(commonPath);
+
+const bench = common.createBenchmark(main, {
+  n: [1000],
+  useCache: ['true', 'false']
+});
+
+function main({ n, useCache }) {
+  const natives = [
+    'vm', 'util', 'child_process', 'dns', 'querystring', 'http', 'process',
+    'http2', 'net', 'os', 'buffer', 'crypto', 'url', 'path', 'string_decoder'
+  ];
+  if (useCache) {
+    for (const name of natives)
+      require(name);
+    require(commonPath);
+  }
+
+  bench.start();
+  for (var i = 0; i < n; i++) {
+    for (var j = 0; j < natives.length; j++)
+      require(natives[j]);
+    // Pretend mixed input (otherwise the results are less representative due to
+    // highly specialized code).
+    require(commonPath);
+  }
+  bench.end(n * (natives.length + 1));
+}
diff --git a/benchmark/module/module-loader-deep.js b/benchmark/module/module-loader-deep.js
new file mode 100644
index 00000000000000..f686b8df47dfba
--- /dev/null
+++ b/benchmark/module/module-loader-deep.js
@@ -0,0 +1,51 @@
+'use strict';
+const fs = require('fs');
+const path = require('path');
+const common = require('../common.js');
+
+const tmpdir = require('../../test/common/tmpdir');
+const benchmarkDirectory = path.join(tmpdir.path, 'nodejs-benchmark-module');
+
+const bench = common.createBenchmark(main, {
+  ext: ['', '.js'],
+  files: [1e3],
+  cache: ['true', 'false']
+});
+
+function main({ ext, cache, files }) {
+  tmpdir.refresh();
+  fs.mkdirSync(benchmarkDirectory);
+  fs.writeFileSync(
+    `${benchmarkDirectory}/a.js`,
+    'module.exports = {};'
+  );
+  for (var i = 0; i <= files; i++) {
+    fs.mkdirSync(`${benchmarkDirectory}/${i}`);
+    fs.writeFileSync(
+      `${benchmarkDirectory}/${i}/package.json`,
+      '{"main": "index.js"}'
+    );
+    fs.writeFileSync(
+      `${benchmarkDirectory}/${i}/index.js`,
+      `require('../a${ext}');`
+    );
+  }
+
+  measureDir(cache === 'true', files);
+
+  tmpdir.refresh();
+}
+
+function measureDir(cache, files) {
+  var i;
+  if (cache) {
+    for (i = 0; i <= files; i++) {
+      require(`${benchmarkDirectory}/${i}`);
+    }
+  }
+  bench.start();
+  for (i = 0; i <= files; i++) {
+    require(`${benchmarkDirectory}/${i}`);
+  }
+  bench.end(files);
+}
diff --git a/benchmark/module/module-loader.js b/benchmark/module/module-loader.js
index e780d6376b5e8d..3b8e9be2d60636 100644
--- a/benchmark/module/module-loader.js
+++ b/benchmark/module/module-loader.js
@@ -1,21 +1,27 @@
 'use strict';
 const fs = require('fs');
 const path = require('path');
+const { builtinModules } = require('module');
 const common = require('../common.js');
 
 const tmpdir = require('../../test/common/tmpdir');
-const benchmarkDirectory = path.join(tmpdir.path, 'nodejs-benchmark-module');
+let benchmarkDirectory = path.join(tmpdir.path, 'nodejs-benchmark-module');
+
+// Filter all irregular modules.
+const otherModules = builtinModules.filter((name) => !/\/|^_|^sys/.test(name));
 
 const bench = common.createBenchmark(main, {
-  n: [5e4],
-  fullPath: ['true', 'false'],
-  useCache: ['true', 'false']
+  name: ['', '/', '/index.js'],
+  dir: ['rel', 'abs'],
+  files: [5e2],
+  n: [1, 1e3],
+  cache: ['true', 'false']
 });
 
-function main({ n, fullPath, useCache }) {
+function main({ n, name, cache, files, dir }) {
   tmpdir.refresh();
-  try { fs.mkdirSync(benchmarkDirectory); } catch {}
-  for (var i = 0; i <= n; i++) {
+  fs.mkdirSync(benchmarkDirectory);
+  for (var i = 0; i <= files; i++) {
     fs.mkdirSync(`${benchmarkDirectory}${i}`);
     fs.writeFileSync(
       `${benchmarkDirectory}${i}/package.json`,
@@ -27,38 +33,28 @@ function main({ n, fullPath, useCache }) {
     );
   }
 
-  if (fullPath === 'true')
-    measureFull(n, useCache === 'true');
-  else
-    measureDir(n, useCache === 'true');
+  if (dir === 'rel')
+    benchmarkDirectory = path.relative(__dirname, benchmarkDirectory);
 
-  tmpdir.refresh();
-}
+  measureDir(n, cache === 'true', files, name);
 
-function measureFull(n, useCache) {
-  var i;
-  if (useCache) {
-    for (i = 0; i <= n; i++) {
-      require(`${benchmarkDirectory}${i}/index.js`);
-    }
-  }
-  bench.start();
-  for (i = 0; i <= n; i++) {
-    require(`${benchmarkDirectory}${i}/index.js`);
-  }
-  bench.end(n);
+  tmpdir.refresh();
 }
 
-function measureDir(n, useCache) {
+function measureDir(n, cache, files, name) {
   var i;
-  if (useCache) {
-    for (i = 0; i <= n; i++) {
-      require(`${benchmarkDirectory}${i}`);
+  if (cache) {
+    for (i = 0; i <= files; i++) {
+      require(`${benchmarkDirectory}${i}${name}`);
     }
   }
   bench.start();
-  for (i = 0; i <= n; i++) {
-    require(`${benchmarkDirectory}${i}`);
+  for (i = 0; i <= files; i++) {
+    for (var j = 0; j < n; j++)
+      require(`${benchmarkDirectory}${i}${name}`);
+    // Pretend mixed input (otherwise the results are less representative due to
+    // highly specialized code).
+    require(otherModules[i % otherModules.length]);
   }
-  bench.end(n);
+  bench.end(n * files);
 }
diff --git a/doc/api/deprecations.md b/doc/api/deprecations.md
index c4fbacc0e0ae46..61a0c11699aa19 100644
--- a/doc/api/deprecations.md
+++ b/doc/api/deprecations.md
@@ -442,6 +442,9 @@ code.
 ### DEP0019: require('.') resolved outside directory
 <!-- YAML
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/REPLACEME
+    description: Removed functionality.
   - version:
     - v4.8.6
     - v6.12.0
@@ -452,11 +455,10 @@ changes:
     description: Runtime deprecation.
 -->
 
-Type: Runtime
+Type: End-of-Life
 
-In certain cases, `require('.')` may resolve outside the package directory.
-This behavior is deprecated and will be removed in a future major Node.js
-release.
+In certain cases, `require('.')` could resolve outside the package directory.
+This behavior has been removed.
 
 <a id="DEP0020"></a>
 ### DEP0020: Server.connections
diff --git a/doc/api/modules.md b/doc/api/modules.md
index 5292d2389760bd..810b887c86c615 100644
--- a/doc/api/modules.md
+++ b/doc/api/modules.md
@@ -196,28 +196,26 @@ NODE_MODULES_PATHS(START)
 
 <!--type=misc-->
 
-Modules are cached after the first time they are loaded. This means
-(among other things) that every call to `require('foo')` will get
-exactly the same object returned, if it would resolve to the same file.
+Modules are cached after the first time they are loaded. This means (among other
+things) that every call to `require('foo')` will get exactly the same object
+returned, if it would resolve to the same file.
 
-Provided `require.cache` is not modified, multiple calls to
-`require('foo')` will not cause the module code to be executed multiple times.
-This is an important feature. With it, "partially done" objects can be returned,
-thus allowing transitive dependencies to be loaded even when they would cause
-cycles.
+Provided `require.cache` is not modified, multiple calls to `require('foo')`
+will not cause the module code to be executed multiple times. This is an
+important feature. With it, "partially done" objects can be returned, thus
+allowing transitive dependencies to be loaded even when they would cause cycles.
 
-To have a module execute code multiple times, export a function, and call
-that function.
+To have a module execute code multiple times, export a function, and call that
+function.
 
 ### Module Caching Caveats
 
 <!--type=misc-->
 
-Modules are cached based on their resolved filename. Since modules may
-resolve to a different filename based on the location of the calling
-module (loading from `node_modules` folders), it is not a *guarantee*
-that `require('foo')` will always return the exact same object, if it
-would resolve to different files.
+Modules are cached based on their resolved filename. Since modules may resolve
+to a different filename based on the location of the calling module (loading
+from `node_modules` folders), it is not a *guarantee* that `require('foo')` will
+always return the exact same object, if it would resolve to different files.
 
 Additionally, on case-insensitive file systems or operating systems, different
 resolved filenames can point to the same file, but the cache will still treat
@@ -412,7 +410,7 @@ are not found elsewhere.
 On Windows, `NODE_PATH` is delimited by semicolons (`;`) instead of colons.
 
 `NODE_PATH` was originally created to support loading modules from
-varying paths before the current [module resolution][] algorithm was frozen.
+varying paths before the current [module resolution][] algorithm was defined.
 
 `NODE_PATH` is still supported, but is less necessary now that the Node.js
 ecosystem has settled on a convention for locating dependent modules.
@@ -582,6 +580,10 @@ value from this object, the next `require` will reload the module. Note that
 this does not apply to [native addons][], for which reloading will result in an
 error.
 
+Adding or replacing entries is also possible. This cache is checked before
+native modules and if such a name is added to the cache, no require call is
+going to receive the native module anymore. Use with care!
+
 #### require.extensions
 <!-- YAML
 added: v0.3.0
@@ -600,22 +602,13 @@ Process files with the extension `.sjs` as `.js`:
 require.extensions['.sjs'] = require.extensions['.js'];
 ```
 
-**Deprecated** In the past, this list has been used to load
-non-JavaScript modules into Node.js by compiling them on-demand.
-However, in practice, there are much better ways to do this, such as
-loading modules via some other Node.js program, or compiling them to
-JavaScript ahead of time.
-
-Since the module system is locked, this feature will probably never go
-away. However, it may have subtle bugs and complexities that are best
-left untouched.
-
-Note that the number of file system operations that the module system
-has to perform in order to resolve a `require(...)` statement to a
-filename scales linearly with the number of registered extensions.
+**Deprecated** In the past, this list has been used to load non-JavaScript
+modules into Node.js by compiling them on-demand. However, in practice, there
+are much better ways to do this, such as loading modules via some other Node.js
+program, or compiling them to JavaScript ahead of time.
 
-In other words, adding extensions slows down the module loader and
-should be discouraged.
+Avoid using `require.extensions`. Use could cause subtle bugs and resolving the
+extensions is becoming slower the more extensions you add.
 
 #### require.main
 <!-- YAML
diff --git a/lib/internal/bootstrap/loaders.js b/lib/internal/bootstrap/loaders.js
index 93fb186574165c..2759bcb65e04a2 100644
--- a/lib/internal/bootstrap/loaders.js
+++ b/lib/internal/bootstrap/loaders.js
@@ -179,21 +179,33 @@ NativeModule._cache = {};
 
 const config = internalBinding('config');
 
+// Do not expose this to user land even with --expose-internals.
+const loaderId = 'internal/bootstrap/loaders';
+
+// Create a native module map to tell if a module is internal or not.
+const moduleState = {};
+const moduleNames = Object.keys(source);
+for (const name of moduleNames) {
+  moduleState[name] = name === loaderId ||
+    !config.exposeInternals &&
+    (name.startsWith('internal/') ||
+      (name === 'worker_threads' && !config.experimentalWorker));
+}
+
 // Think of this as module.exports in this file even though it is not
 // written in CommonJS style.
 const loaderExports = { internalBinding, NativeModule };
-const loaderId = 'internal/bootstrap/loaders';
 
 NativeModule.require = function(id) {
-  if (id === loaderId) {
-    return loaderExports;
-  }
-
   const cached = NativeModule.getCached(id);
-  if (cached && (cached.loaded || cached.loading)) {
+  if (cached !== undefined && (cached.loaded || cached.loading)) {
     return cached.exports;
   }
 
+  if (id === loaderId) {
+    return loaderExports;
+  }
+
   if (!NativeModule.exists(id)) {
     // Model the error off the internal/errors.js model, but
     // do not use that module given that it could actually be
@@ -231,32 +243,16 @@ NativeModule.getCached = function(id) {
 };
 
 NativeModule.exists = function(id) {
-  return NativeModule._source.hasOwnProperty(id);
+  return NativeModule._source[id] !== undefined;
 };
 
-if (config.exposeInternals) {
-  NativeModule.nonInternalExists = function(id) {
-    // Do not expose this to user land even with --expose-internals.
-    if (id === loaderId) {
-      return false;
-    }
-    return NativeModule.exists(id);
-  };
-
-  NativeModule.isInternal = function(id) {
-    // Do not expose this to user land even with --expose-internals.
-    return id === loaderId;
-  };
-} else {
-  NativeModule.nonInternalExists = function(id) {
-    return NativeModule.exists(id) && !NativeModule.isInternal(id);
-  };
+NativeModule.nonInternalExists = function(id) {
+  return moduleState[id] === false;
+};
 
-  NativeModule.isInternal = function(id) {
-    return id.startsWith('internal/') ||
-        (id === 'worker_threads' && !config.experimentalWorker);
-  };
-}
+NativeModule.isInternal = function(id) {
+  return moduleState[id] === true;
+};
 
 NativeModule.getSource = function(id) {
   return NativeModule._source[id];
diff --git a/lib/internal/modules/cjs/helpers.js b/lib/internal/modules/cjs/helpers.js
index fcb536c3df3738..daec2744c7e6d8 100644
--- a/lib/internal/modules/cjs/helpers.js
+++ b/lib/internal/modules/cjs/helpers.js
@@ -1,15 +1,13 @@
 'use strict';
 
 const { validateString } = require('internal/validators');
-
-const {
-  CHAR_LINE_FEED,
-  CHAR_CARRIAGE_RETURN,
-  CHAR_EXCLAMATION_MARK,
-  CHAR_HASH,
-} = require('internal/constants');
-
 const { getOptionValue } = require('internal/options');
+const {
+  ERR_INVALID_ARG_TYPE,
+  ERR_OUT_OF_RANGE
+} = require('internal/errors').codes;
+const { NativeModule } = require('internal/bootstrap/loaders');
+const { isAbsolute } = require('path');
 
 // Invoke with makeRequireFunction(module) where |module| is the Module object
 // to use as the context for the require() function.
@@ -17,17 +15,37 @@ function makeRequireFunction(mod) {
   const Module = mod.constructor;
 
   function require(path) {
-    try {
-      exports.requireDepth += 1;
-      return mod.require(path);
-    } finally {
-      exports.requireDepth -= 1;
-    }
+    return mod.require(path);
   }
 
   function resolve(request, options) {
     validateString(request, 'request');
-    return Module._resolveFilename(request, mod, false, options);
+    let paths;
+    if (options !== undefined && options.paths !== undefined) {
+      if (!Array.isArray(options.paths)) {
+        throw new ERR_INVALID_ARG_TYPE('options.paths', 'Array', options.paths);
+      }
+      if (options.paths.length === 0) {
+        throw new ERR_OUT_OF_RANGE('options.paths.length', '> 0',
+                                   options.paths.length);
+      }
+      if (!isAbsolute(request) &&
+          (request.charAt(0) !== '.' ||
+           (request.length > 1 &&
+            request.charAt(1) !== '.' &&
+            request.charAt(1) !== '/' &&
+            (process.platform !== 'win32' || request.charAt(1) !== '\\')))) {
+        const tmpPaths = new Set();
+        options.paths.forEach((path) =>
+          Module._nodeModulePaths(path).forEach((modPath) =>
+            tmpPaths.add(modPath)));
+        paths = [...tmpPaths];
+      }
+    }
+    if (NativeModule.nonInternalExists(request)) {
+      return request;
+    }
+    return Module._resolveFilename(request, mod, false, paths);
   }
 
   require.resolve = resolve;
@@ -66,31 +84,17 @@ function stripBOM(content) {
  */
 function stripShebang(content) {
   // Remove shebang
-  var contLen = content.length;
-  if (contLen >= 2) {
-    if (content.charCodeAt(0) === CHAR_HASH &&
-        content.charCodeAt(1) === CHAR_EXCLAMATION_MARK) {
-      if (contLen === 2) {
-        // Exact match
-        content = '';
-      } else {
-        // Find end of shebang line and slice it off
-        var i = 2;
-        for (; i < contLen; ++i) {
-          var code = content.charCodeAt(i);
-          if (code === CHAR_LINE_FEED || code === CHAR_CARRIAGE_RETURN)
-            break;
-        }
-        if (i === contLen)
-          content = '';
-        else {
-          // Note that this actually includes the newline character(s) in the
-          // new output. This duplicates the behavior of the regular expression
-          // that was previously used to replace the shebang line
-          content = content.slice(i);
-        }
-      }
-    }
+  if (content.charAt(0) === '#' && content.charAt(1) === '!') {
+    // Find end of shebang line and slice it off
+    let index = content.indexOf('\n', 2);
+    if (index === -1)
+      return '';
+    if (content.charAt(index - 1) === '\r')
+      index--;
+    // Note that this actually includes the newline character(s) in the
+    // new output. This duplicates the behavior of the regular expression
+    // that was previously used to replace the shebang line
+    content = content.slice(index);
   }
   return content;
 }
diff --git a/lib/internal/modules/cjs/loader.js b/lib/internal/modules/cjs/loader.js
index bf6a9d4029c2a5..94411c1269747c 100644
--- a/lib/internal/modules/cjs/loader.js
+++ b/lib/internal/modules/cjs/loader.js
@@ -37,10 +37,12 @@ const {
 const { safeGetenv } = internalBinding('credentials');
 const {
   makeRequireFunction,
-  requireDepth,
   stripBOM,
   stripShebang
 } = require('internal/modules/cjs/helpers');
+const {
+  decorateErrorStack
+} = require('internal/util');
 const { getOptionValue } = require('internal/options');
 const preserveSymlinks = getOptionValue('--preserve-symlinks');
 const preserveSymlinksMain = getOptionValue('--preserve-symlinks-main');
@@ -52,64 +54,51 @@ const {
 } = require('internal/errors').codes;
 const { validateString } = require('internal/validators');
 
-module.exports = Module;
-
 let asyncESM;
 let ModuleJob;
 let createDynamicModule;
-let decorateErrorStack;
-
-function lazyLoadESM() {
-  asyncESM = require('internal/process/esm_loader');
-  ModuleJob = require('internal/modules/esm/module_job');
-  createDynamicModule = require(
-    'internal/modules/esm/create_dynamic_module');
-  decorateErrorStack = require('internal/util').decorateErrorStack;
-}
+let extensionNames;
+let extensionCopy;
+let getNodeModulePaths;
 
 const {
-  CHAR_UPPERCASE_A,
-  CHAR_LOWERCASE_A,
-  CHAR_UPPERCASE_Z,
-  CHAR_LOWERCASE_Z,
   CHAR_FORWARD_SLASH,
   CHAR_BACKWARD_SLASH,
   CHAR_COLON,
   CHAR_DOT,
-  CHAR_UNDERSCORE,
-  CHAR_0,
-  CHAR_9,
 } = require('internal/constants');
 
 const isWindows = process.platform === 'win32';
 
+const statCache = new Map();
 function stat(filename) {
   filename = path.toNamespacedPath(filename);
-  const cache = stat.cache;
-  if (cache !== null) {
-    const result = cache.get(filename);
-    if (result !== undefined) return result;
-  }
-  const result = internalModuleStat(filename);
-  if (cache !== null) cache.set(filename, result);
+  let result = statCache.get(filename);
+  if (result !== undefined)
+    return result;
+  result = internalModuleStat(filename);
+  if (statCache.size < 1e4)
+    statCache.set(filename, result);
   return result;
 }
-stat.cache = null;
 
-function updateChildren(parent, child, scan) {
-  var children = parent && parent.children;
-  if (children && !(scan && children.includes(child)))
+function updateChildren(parent, child) {
+  const children = parent.children;
+  if (children.indexOf(child) === -1)
     children.push(child);
 }
 
-function Module(id, parent) {
+function Module(id = '', parent) {
   this.id = id;
+  this.path = path.dirname(id);
   this.exports = {};
   this.parent = parent;
-  updateChildren(parent, this, false);
   this.filename = null;
   this.loaded = false;
   this.children = [];
+  this.paths = undefined;
+  if (parent !== undefined)
+    parent.children.push(this);
 }
 
 const builtinModules = Object.keys(NativeModule._source)
@@ -120,8 +109,7 @@ Module.builtinModules = builtinModules;
 
 Module._cache = Object.create(null);
 Module._pathCache = Object.create(null);
-Module._extensions = Object.create(null);
-var modulePaths = [];
+let modulePaths = [];
 Module.globalPaths = [];
 
 Module.wrap = function(script) {
@@ -149,39 +137,33 @@ Module._debug = util.deprecate(debug, 'Module._debug is deprecated.',
 //   -> a.<ext>
 //   -> a/index.<ext>
 
-// check if the directory is a package.json dir
-const packageMainCache = Object.create(null);
-
+// Check if the directory is a package.json dir
 function readPackage(requestPath) {
-  const entry = packageMainCache[requestPath];
-  if (entry)
-    return entry;
-
-  const jsonPath = path.resolve(requestPath, 'package.json');
+  const jsonPath = `${requestPath}${path.sep}package.json`;
   const json = internalModuleReadJSON(path.toNamespacedPath(jsonPath));
 
   if (json === undefined) {
-    return false;
+    return '';
   }
 
   try {
-    return packageMainCache[requestPath] = JSON.parse(json).main;
+    return JSON.parse(json).main;
   } catch (e) {
     e.path = jsonPath;
-    e.message = 'Error parsing ' + jsonPath + ': ' + e.message;
+    e.message = `Error parsing ${jsonPath}: ${e.message}`;
     throw e;
   }
 }
 
-function tryPackage(requestPath, exts, isMain) {
-  var pkg = readPackage(requestPath);
+function tryPackage(requestPath, isMain) {
+  const pkg = readPackage(requestPath);
 
-  if (!pkg) return false;
+  if (!pkg) return '';
 
-  var filename = path.resolve(requestPath, pkg);
+  const filename = path.resolve(requestPath, pkg);
   return tryFile(filename, isMain) ||
-         tryExtensions(filename, exts, isMain) ||
-         tryExtensions(path.resolve(filename, 'index'), exts, isMain);
+         tryExtensions(filename, isMain) ||
+         tryExtensions(`${filename}${path.sep}index`, isMain);
 }
 
 // In order to minimize unnecessary lstat() calls,
@@ -189,16 +171,19 @@ function tryPackage(requestPath, exts, isMain) {
 // Set to an empty Map to reset.
 const realpathCache = new Map();
 
-// check if the file exists and is not a directory
+// Check if the file exists and is not a directory
 // if using --preserve-symlinks and isMain is false,
 // keep symlinks intact, otherwise resolve to the
 // absolute realpath.
 function tryFile(requestPath, isMain) {
   const rc = stat(requestPath);
+  if (rc !== 0) {
+    return '';
+  }
   if (preserveSymlinks && !isMain) {
-    return rc === 0 && path.resolve(requestPath);
+    return requestPath;
   }
-  return rc === 0 && toRealPath(requestPath);
+  return toRealPath(requestPath);
 }
 
 function toRealPath(requestPath) {
@@ -207,16 +192,16 @@ function toRealPath(requestPath) {
   });
 }
 
-// Given a path, check if the file exists with any of the set extensions
-function tryExtensions(p, exts, isMain) {
-  for (var i = 0; i < exts.length; i++) {
-    const filename = tryFile(p + exts[i], isMain);
+// Given a path, check if the file exists with any of the set extensions.
+function tryExtensions(p, isMain) {
+  for (var i = 0; i < extensionNames.length; i++) {
+    const filename = tryFile(`${p}${extensionNames[i]}`, isMain);
 
-    if (filename) {
+    if (filename !== '') {
       return filename;
     }
   }
-  return false;
+  return '';
 }
 
 // Find the longest (possibly multi-dot) extension registered in
@@ -224,56 +209,65 @@ function tryExtensions(p, exts, isMain) {
 function findLongestRegisteredExtension(filename) {
   const name = path.basename(filename);
   let currentExtension;
-  let index;
-  let startIndex = 0;
-  while ((index = name.indexOf('.', startIndex)) !== -1) {
-    startIndex = index + 1;
-    if (index === 0) continue; // Skip dotfiles like .gitignore
+  let index = 0;
+  do {
+    index = name.indexOf('.', index);
     currentExtension = name.slice(index);
-    if (Module._extensions[currentExtension]) return currentExtension;
-  }
+    if (extensionCopy[currentExtension]) {
+      if (index === 0)
+        continue; // Skip dotfiles like .gitignore
+      return currentExtension;
+    }
+  } while (index++ !== -1);
   return '.js';
 }
 
-var warned = false;
-Module._findPath = function(request, paths, isMain) {
-  if (path.isAbsolute(request)) {
-    paths = [''];
-  } else if (!paths || paths.length === 0) {
+function hasTrailingSlash(request) {
+  let char = request.charCodeAt(request.length - 1);
+  if (char === CHAR_FORWARD_SLASH) {
+    return true;
+  }
+  if (char !== CHAR_DOT) {
     return false;
   }
-
-  var cacheKey = request + '\x00' +
-                (paths.length === 1 ? paths[0] : paths.join('\x00'));
-  var entry = Module._pathCache[cacheKey];
-  if (entry)
-    return entry;
-
-  var exts;
-  var trailingSlash = request.length > 0 &&
-    request.charCodeAt(request.length - 1) === CHAR_FORWARD_SLASH;
-  if (!trailingSlash) {
-    trailingSlash = /(?:^|\/)\.?\.$/.test(request);
+  if (request.length === 1) {
+    return true;
+  }
+  char = request.charCodeAt(request.length - 2);
+  if (char === CHAR_DOT) {
+    return request.length === 2 ||
+      request.charCodeAt(request.length - 3) === CHAR_FORWARD_SLASH;
   }
+  return char === CHAR_FORWARD_SLASH;
+}
+
+Module._findPath = function(request, paths, isMain) {
+  let trailingSlash = false;
 
   // For each path
   for (var i = 0; i < paths.length; i++) {
     // Don't search further if path doesn't exist
     const curPath = paths[i];
-    if (curPath && stat(curPath) < 1) continue;
-    var basePath = path.resolve(curPath, request);
-    var filename;
+    const cacheKey = `${request}\x00${curPath}`;
+    const cache = Module._pathCache[cacheKey];
+    if (cache !== undefined) {
+      if (cache === '') // Path does not contain anything.
+        continue;
+      return cache;
+    }
+    if (i === 0)
+      trailingSlash = hasTrailingSlash(request);
+
+    const basePath = curPath !== '' ?
+      path.resolve(curPath, request) :
+      path.resolve(request);
 
-    var rc = stat(basePath);
-    if (!trailingSlash) {
+    let filename = '';
+
+    const rc = stat(basePath);
+    if (rc !== -1 && !trailingSlash) {
       if (rc === 0) {  // File.
-        if (!isMain) {
-          if (preserveSymlinks) {
-            filename = path.resolve(basePath);
-          } else {
-            filename = toRealPath(basePath);
-          }
-        } else if (preserveSymlinksMain) {
+        if (!isMain && preserveSymlinks || preserveSymlinksMain) {
           // For the main module, we use the preserveSymlinksMain flag instead
           // mainly for backward compatibility, as the preserveSymlinks flag
           // historically has not applied to the main module.  Most likely this
@@ -282,72 +276,63 @@ Module._findPath = function(request, paths, isMain) {
           // files to resolve; that said, in some use cases following symlinks
           // causes bigger problems which is why the preserveSymlinksMain option
           // is needed.
-          filename = path.resolve(basePath);
+          filename = basePath;
         } else {
           filename = toRealPath(basePath);
         }
-      }
-
-      if (!filename) {
-        // try it with each of the extensions
-        if (exts === undefined)
-          exts = Object.keys(Module._extensions);
-        filename = tryExtensions(basePath, exts, isMain);
+      } else {
+        // Try it with each of the extensions
+        filename = tryExtensions(basePath, isMain);
       }
     }
 
-    if (!filename && rc === 1) {  // Directory.
-      // try it with each of the extensions at "index"
-      if (exts === undefined)
-        exts = Object.keys(Module._extensions);
-      filename = tryPackage(basePath, exts, isMain);
-      if (!filename) {
-        filename = tryExtensions(path.resolve(basePath, 'index'), exts, isMain);
+    if (rc === 1 && filename === '') {  // Directory.
+      // Try it with each of the extensions at "index"
+      filename = tryPackage(basePath, isMain);
+      if (filename === '') {
+        filename = tryExtensions(`${basePath}${path.sep}index`, isMain);
       }
     }
 
-    if (filename) {
-      // Warn once if '.' resolved outside the module dir
-      if (request === '.' && i > 0) {
-        if (!warned) {
-          warned = true;
-          process.emitWarning(
-            'warning: require(\'.\') resolved outside the package ' +
-            'directory. This functionality is deprecated and will be removed ' +
-            'soon.',
-            'DeprecationWarning', 'DEP0019');
-        }
-      }
-
+    if (filename !== '') {
       Module._pathCache[cacheKey] = filename;
       return filename;
     }
-  }
-  return false;
+    // Signal that we already checked this path and that it did not contain
+    // a file.
+    Module._pathCache[cacheKey] = '';
+  }
+  // eslint-disable-next-line no-restricted-syntax
+  const err = new Error(`Cannot find module '${request}'`);
+  err.code = 'MODULE_NOT_FOUND';
+  throw err;
+};
+
+// This wrapper exists for backwards compatibility. It just guarantees that
+// `from` is absolute.
+Module._nodeModulePaths = function(from) {
+  return getNodeModulePaths(path.resolve(from));
 };
 
 // 'node_modules' character codes reversed
-var nmChars = [ 115, 101, 108, 117, 100, 111, 109, 95, 101, 100, 111, 110 ];
-var nmLen = nmChars.length;
+const nmChars = [115, 101, 108, 117, 100, 111, 109, 95, 101, 100, 111, 110];
 if (isWindows) {
   // 'from' is the __dirname of the module.
-  Module._nodeModulePaths = function(from) {
-    // guarantee that 'from' is absolute.
-    from = path.resolve(from);
-
-    // note: this approach *only* works when the path is guaranteed
+  getNodeModulePaths = (from) => {
+    // Note: this approach *only* works when the path is guaranteed
     // to be absolute.  Doing a fully-edge-case-correct path.split
     // that works on both Windows and Posix is non-trivial.
 
-    // return root node_modules when path is 'D:\\'.
+    // Return root node_modules when path is 'D:\\'.
     // path.resolve will make sure from.length >=3 in Windows.
     if (from.charCodeAt(from.length - 1) === CHAR_BACKWARD_SLASH &&
-        from.charCodeAt(from.length - 2) === CHAR_COLON)
-      return [from + 'node_modules'];
+        from.charCodeAt(from.length - 2) === CHAR_COLON) {
+      return [`${from}node_modules`];
+    }
 
     const paths = [];
-    var p = 0;
-    var last = from.length;
+    let p = 0;
+    let last = from.length;
     for (var i = from.length - 1; i >= 0; --i) {
       const code = from.charCodeAt(i);
       // The path segment separator check ('\' and '/') was used to get
@@ -358,8 +343,8 @@ if (isWindows) {
       if (code === CHAR_BACKWARD_SLASH ||
           code === CHAR_FORWARD_SLASH ||
           code === CHAR_COLON) {
-        if (p !== nmLen)
-          paths.push(from.slice(0, last) + '\\node_modules');
+        if (p !== nmChars.length)
+          paths.push(`${from.slice(0, last)}\\node_modules`);
         last = i;
         p = 0;
       } else if (p !== -1) {
@@ -370,30 +355,31 @@ if (isWindows) {
         }
       }
     }
-
     return paths;
   };
-} else { // posix
-  // 'from' is the __dirname of the module.
-  Module._nodeModulePaths = function(from) {
-    // guarantee that 'from' is absolute.
-    from = path.resolve(from);
+} else { // Posix
+  getNodeModulePaths = (from) => {
+    // TODO(BridgeAR): Consider checking for the directory existence and to only
+    // return existing ones + adding a local cache to prevent calculating the
+    // path again for the same directory. This would slow down this function
+    // while decreasing the amount of `_pathCache` entries.
+
     // Return early not only to avoid unnecessary work, but to *avoid* returning
     // an array of two items for a root: [ '//node_modules', '/node_modules' ]
-    if (from === '/')
+    if (from.length === 1)
       return ['/node_modules'];
 
-    // note: this approach *only* works when the path is guaranteed
+    // Note: this approach *only* works when the path is guaranteed
     // to be absolute.  Doing a fully-edge-case-correct path.split
     // that works on both Windows and Posix is non-trivial.
     const paths = [];
-    var p = 0;
-    var last = from.length;
+    let p = 0;
+    let last = from.length;
     for (var i = from.length - 1; i >= 0; --i) {
       const code = from.charCodeAt(i);
       if (code === CHAR_FORWARD_SLASH) {
-        if (p !== nmLen)
-          paths.push(from.slice(0, last) + '/node_modules');
+        if (p !== nmChars.length)
+          paths.push(`${from.slice(0, last)}/node_modules`);
         last = i;
         p = 0;
       } else if (p !== -1) {
@@ -407,140 +393,112 @@ if (isWindows) {
 
     // Append /node_modules to handle root paths.
     paths.push('/node_modules');
-
     return paths;
   };
 }
 
-
-// 'index.' character codes
-var indexChars = [ 105, 110, 100, 101, 120, 46 ];
-var indexLen = indexChars.length;
-Module._resolveLookupPaths = function(request, parent, newReturn) {
-  if (NativeModule.nonInternalExists(request)) {
-    debug('looking for %j in []', request);
-    return (newReturn ? null : [request, []]);
-  }
-
-  // Check for non-relative path
-  if (request.length < 2 ||
-      request.charCodeAt(0) !== CHAR_DOT ||
-      (request.charCodeAt(1) !== CHAR_DOT &&
-       request.charCodeAt(1) !== CHAR_FORWARD_SLASH &&
-       (!isWindows || request.charCodeAt(1) !== CHAR_BACKWARD_SLASH))) {
-    var paths = modulePaths;
-    if (parent) {
-      if (!parent.paths)
-        paths = parent.paths = [];
-      else
-        paths = parent.paths.concat(paths);
+// Keep backwards compatible return value.
+// TODO: Deprecate the direct access and recommend to use the public
+// require.paths() function instead.
+Module._resolveLookupPaths =
+  function _resolveLookupPaths(request, parent, newReturn) {
+    if (NativeModule.nonInternalExists(request)) {
+      return newReturn ? null : [request, []];
     }
+    const paths = resolveLookupPaths(request, parent);
+    return newReturn ? paths : [request, paths];
+  };
 
-    // Maintain backwards compat with certain broken uses of require('.')
-    // by putting the module's directory in front of the lookup paths.
-    if (request === '.') {
-      if (parent && parent.filename) {
-        paths.unshift(path.dirname(parent.filename));
-      } else {
-        paths.unshift(path.resolve(request));
-      }
+function resolveLookupPaths(request, parent) {
+  if (path.isAbsolute(request)) {
+    debug('looking for absolute path "%s"', request);
+    return [''];
+  }
+
+  // Check for node modules paths.
+  if (request.charAt(0) !== '.' ||
+      (request.length > 1 &&
+       request.charAt(1) !== '.' &&
+       request.charAt(1) !== '/' &&
+       (!isWindows || request.charAt(1) !== '\\'))) {
+    let paths = modulePaths;
+    if (parent != null && parent.paths.length) {
+      paths = parent.paths.concat(paths);
     }
 
-    debug('looking for %j in %j', request, paths);
-    return (newReturn ? (paths.length > 0 ? paths : null) : [request, paths]);
+    debug('looking for "%s" in %j', request, paths);
+    return paths;
   }
 
-  // with --eval, parent.id is not set and parent.filename is null
+  // With --eval, parent.id is not set and parent.filename is null.
   if (!parent || !parent.id || !parent.filename) {
     // Make require('./path/to/foo') work - normally the path is taken
     // from realpath(__filename) but with eval there is no filename
-    var mainPaths = ['.'].concat(Module._nodeModulePaths('.'), modulePaths);
-
-    debug('looking for %j in %j', request, mainPaths);
-    return (newReturn ? mainPaths : [request, mainPaths]);
-  }
-
-  // Is the parent an index module?
-  // We can assume the parent has a valid extension,
-  // as it already has been accepted as a module.
-  const base = path.basename(parent.filename);
-  var parentIdPath;
-  if (base.length > indexLen) {
-    var i = 0;
-    for (; i < indexLen; ++i) {
-      if (indexChars[i] !== base.charCodeAt(i))
-        break;
-    }
-    if (i === indexLen) {
-      // We matched 'index.', let's validate the rest
-      for (; i < base.length; ++i) {
-        const code = base.charCodeAt(i);
-        if (code !== CHAR_UNDERSCORE &&
-            (code < CHAR_0 || code > CHAR_9) &&
-            (code < CHAR_UPPERCASE_A || code > CHAR_UPPERCASE_Z) &&
-            (code < CHAR_LOWERCASE_A || code > CHAR_LOWERCASE_Z))
-          break;
-      }
-      if (i === base.length) {
-        // Is an index module
-        parentIdPath = parent.id;
-      } else {
-        // Not an index module
-        parentIdPath = path.dirname(parent.id);
-      }
-    } else {
-      // Not an index module
-      parentIdPath = path.dirname(parent.id);
-    }
-  } else {
-    // Not an index module
-    parentIdPath = path.dirname(parent.id);
-  }
-  var id = path.resolve(parentIdPath, request);
+    const mainPaths = ['.'].concat(
+      getNodeModulePaths(process.cwd()),
+      modulePaths
+    );
 
-  // Make sure require('./path') and require('path') get distinct ids, even
-  // when called from the toplevel js file
-  if (parentIdPath === '.' &&
-      id.indexOf('/') === -1 &&
-      (!isWindows || id.indexOf('\\') === -1)) {
-    id = './' + id;
+    debug('looking for "%s" in %j', request, mainPaths);
+    return mainPaths;
   }
 
-  debug('RELATIVE: requested: %s set ID to: %s from %s', request, id,
-        parent.id);
+  // TODO(BridgeAR): This is for backwards compatibility. We should deprecate
+  // passing through own parent objects and recommend the public
+  // `resolve.paths()` API instead. For example
+  // https://github.com/sindresorhus/resolve-from would break without this.
+  if (parent.path === undefined) {
+    return [path.dirname(parent.id)];
+  }
 
-  var parentDir = [path.dirname(parent.filename)];
-  debug('looking for %j in %j', id, parentDir);
-  return (newReturn ? parentDir : [id, parentDir]);
-};
+  return [parent.path];
+}
 
-// Check the cache for the requested file.
-// 1. If a module already exists in the cache: return its exports object.
-// 2. If the module is native: call `NativeModule.require()` with the
-//    filename and return the result.
-// 3. Otherwise, create a new module for the file and save it to the cache.
-//    Then have it load  the file contents before returning its exports
-//    object.
+const filenameCache = Object.create(null);
 Module._load = function(request, parent, isMain) {
-  if (parent) {
+  let identifier;
+  if (parent !== undefined) {
     debug('Module._load REQUEST %s parent: %s', request, parent.id);
+    // Fast path for (lazy loaded) modules in the same directory. The indirect
+    // caching is required to allow cache invalidation without changing the old
+    // cache key names.
+    identifier = `${parent.path}\x00${request}`;
+    const filename = filenameCache[identifier];
+    if (filename !== undefined) {
+      const cachedModule = Module._cache[filename];
+      if (cachedModule !== undefined) {
+        updateChildren(parent, cachedModule, true);
+        return cachedModule.exports;
+      }
+      delete filenameCache[identifier];
+    }
   }
 
-  var filename = Module._resolveFilename(request, parent, isMain);
-
-  var cachedModule = Module._cache[filename];
-  if (cachedModule) {
-    updateChildren(parent, cachedModule, true);
-    return cachedModule.exports;
+  if (NativeModule.nonInternalExists(request)) {
+    // Check for native modules first. If we find such name in the user module
+    // cache, bail out. This keeps the behavior backwards compatible. It was
+    // originally meant to allow mocking of whole modules by placing a native
+    // module name in there.
+    if (Module._cache[request] !== undefined) {
+      if (parent !== undefined)
+        updateChildren(parent, Module._cache[request], true);
+      return Module._cache[request].exports;
+    }
+    debug('load native module %s', request);
+    return NativeModule.require(request);
   }
 
-  if (NativeModule.nonInternalExists(filename)) {
-    debug('load native module %s', request);
-    return NativeModule.require(filename);
+  const filename = Module._resolveFilename(request, parent, isMain);
+
+  const cachedModule = Module._cache[filename];
+  if (cachedModule !== undefined) {
+    if (parent !== undefined)
+      updateChildren(parent, cachedModule, true);
+    return cachedModule.exports;
   }
 
   // Don't call updateChildren(), Module constructor already does.
-  var module = new Module(filename, parent);
+  const module = new Module(filename, parent);
 
   if (isMain) {
     process.mainModule = module;
@@ -548,87 +506,54 @@ Module._load = function(request, parent, isMain) {
   }
 
   Module._cache[filename] = module;
+  if (parent !== undefined)
+    filenameCache[identifier] = filename;
 
-  tryModuleLoad(module, filename);
-
-  return module.exports;
-};
-
-function tryModuleLoad(module, filename) {
-  var threw = true;
+  let threw = true;
   try {
     module.load(filename);
     threw = false;
   } finally {
     if (threw) {
       delete Module._cache[filename];
+      if (parent !== undefined)
+        delete filenameCache[identifier];
     }
   }
-}
-
-Module._resolveFilename = function(request, parent, isMain, options) {
-  if (NativeModule.nonInternalExists(request)) {
-    return request;
-  }
-
-  var paths;
-
-  if (typeof options === 'object' && options !== null &&
-      Array.isArray(options.paths)) {
-    const fakeParent = new Module('', null);
 
-    paths = [];
+  return module.exports;
+};
 
-    for (var i = 0; i < options.paths.length; i++) {
-      const path = options.paths[i];
-      fakeParent.paths = Module._nodeModulePaths(path);
-      const lookupPaths = Module._resolveLookupPaths(request, fakeParent, true);
+Module._resolveFilename = function(request, parent, isMain, paths) {
+  if (paths === undefined)
+    paths = resolveLookupPaths(request, parent);
 
-      for (var j = 0; j < lookupPaths.length; j++) {
-        if (!paths.includes(lookupPaths[j]))
-          paths.push(lookupPaths[j]);
-      }
-    }
-  } else {
-    paths = Module._resolveLookupPaths(request, parent, true);
-  }
-
-  // Look up the filename first, since that's the cache key.
-  var filename = Module._findPath(request, paths, isMain);
-  if (!filename) {
-    // eslint-disable-next-line no-restricted-syntax
-    var err = new Error(`Cannot find module '${request}'`);
-    err.code = 'MODULE_NOT_FOUND';
-    throw err;
-  }
-  return filename;
+  return Module._findPath(request, paths, isMain);
 };
 
-
 // Given a file name, pass it to the proper extension handler.
 Module.prototype.load = function(filename) {
-  debug('load %j for module %j', filename, this.id);
+  debug('load "%s" for module "%s"', filename, this.id);
 
   assert(!this.loaded);
   this.filename = filename;
-  this.paths = Module._nodeModulePaths(path.dirname(filename));
+  this.paths = getNodeModulePaths(this.path);
 
-  var extension = findLongestRegisteredExtension(filename);
+  const extension = findLongestRegisteredExtension(filename);
   Module._extensions[extension](this, filename);
   this.loaded = true;
 
   if (experimentalModules) {
-    if (asyncESM === undefined) lazyLoadESM();
     const ESMLoader = asyncESM.ESMLoader;
     const url = `${pathToFileURL(filename)}`;
     const module = ESMLoader.moduleMap.get(url);
     // Create module entry at load time to snapshot exports correctly
     const exports = this.exports;
-    if (module !== undefined) { // called from cjs translator
+    if (module !== undefined) { // Called from cjs translator
       module.reflect.onReady((reflect) => {
         reflect.exports.default.set(exports);
       });
-    } else { // preemptively cache
+    } else { // Preemptively cache
       ESMLoader.moduleMap.set(
         url,
         new ModuleJob(ESMLoader, url, async () => {
@@ -642,7 +567,6 @@ Module.prototype.load = function(filename) {
   }
 };
 
-
 // Loads a module at the given file path. Returns that module's
 // `exports` property.
 Module.prototype.require = function(id) {
@@ -654,10 +578,9 @@ Module.prototype.require = function(id) {
   return Module._load(id, this, /* isMain */ false);
 };
 
-
 // Resolved path to process.argv[1] will be lazily placed here
 // (needed for setting breakpoint when called with --inspect-brk)
-var resolvedArgv;
+let resolvedArgv;
 
 function normalizeReferrerURL(referrer) {
   if (typeof referrer === 'string' && path.isAbsolute(referrer)) {
@@ -666,99 +589,56 @@ function normalizeReferrerURL(referrer) {
   return new URL(referrer).href;
 }
 
-
 // Run the file contents in the correct scope or sandbox. Expose
 // the correct helper variables (require, module, exports) to
 // the file.
 // Returns exception, if any.
 Module.prototype._compile = function(content, filename) {
-
   content = stripShebang(content);
 
-  // create wrapper function
-  var wrapper = Module.wrap(content);
+  // Create wrapper function
+  const wrapper = Module.wrap(content);
 
-  var compiledWrapper = vm.runInThisContext(wrapper, {
+  const compiledWrapper = vm.runInThisContext(wrapper, {
     filename: filename,
     lineOffset: 0,
     displayErrors: true,
     importModuleDynamically: experimentalModules ? async (specifier) => {
-      if (asyncESM === undefined) lazyLoadESM();
       const loader = await asyncESM.loaderPromise;
       return loader.import(specifier, normalizeReferrerURL(filename));
     } : undefined,
   });
 
-  var inspectorWrapper = null;
-  if (process._breakFirstLine && process._eval == null) {
-    if (!resolvedArgv) {
-      // We enter the repl if we're not given a filename argument.
-      if (process.argv[1]) {
-        resolvedArgv = Module._resolveFilename(process.argv[1], null, false);
+  const require = makeRequireFunction(this);
+
+  if (process._breakFirstLine && process._eval == null && !resolvedArgv) {
+    // We enter the repl if we're not given a filename argument.
+    if (process.argv[1]) {
+      if (NativeModule.nonInternalExists(process.argv[1])) {
+        resolvedArgv = process.argv[1];
       } else {
-        resolvedArgv = 'repl';
+        resolvedArgv = Module._resolveFilename(process.argv[1], null, false);
       }
+    } else {
+      resolvedArgv = 'repl';
     }
-
     // Set breakpoint on module start
     if (filename === resolvedArgv) {
       delete process._breakFirstLine;
-      inspectorWrapper = internalBinding('inspector').callAndPauseOnStart;
+      const inspectorWrapper = internalBinding('inspector').callAndPauseOnStart;
+      return inspectorWrapper(compiledWrapper, this.exports, this.exports,
+                              require, this, filename, this.path);
     }
   }
-  var dirname = path.dirname(filename);
-  var require = makeRequireFunction(this);
-  var depth = requireDepth;
-  if (depth === 0) stat.cache = new Map();
-  var result;
-  if (inspectorWrapper) {
-    result = inspectorWrapper(compiledWrapper, this.exports, this.exports,
-                              require, this, filename, dirname);
-  } else {
-    result = compiledWrapper.call(this.exports, this.exports, require, this,
-                                  filename, dirname);
-  }
-  if (depth === 0) stat.cache = null;
-  return result;
-};
-
-
-// Native extension for .js
-Module._extensions['.js'] = function(module, filename) {
-  var content = fs.readFileSync(filename, 'utf8');
-  module._compile(stripBOM(content), filename);
-};
-
-
-// Native extension for .json
-Module._extensions['.json'] = function(module, filename) {
-  var content = fs.readFileSync(filename, 'utf8');
-  try {
-    module.exports = JSON.parse(stripBOM(content));
-  } catch (err) {
-    err.message = filename + ': ' + err.message;
-    throw err;
-  }
-};
 
-
-// Native extension for .node
-Module._extensions['.node'] = function(module, filename) {
-  return process.dlopen(module, path.toNamespacedPath(filename));
+  return compiledWrapper.call(this.exports, this.exports, require, this,
+                              filename, this.path);
 };
 
-if (experimentalModules) {
-  if (asyncESM === undefined) lazyLoadESM();
-  Module._extensions['.mjs'] = function(module, filename) {
-    throw new ERR_REQUIRE_ESM(filename);
-  };
-}
-
-// bootstrap main module.
+// Bootstrap main module.
 Module.runMain = function() {
   // Load the main module--the command line argument.
   if (experimentalModules) {
-    if (asyncESM === undefined) lazyLoadESM();
     asyncESM.loaderPromise.then((loader) => {
       return loader.import(pathToFileURL(process.argv[1]).pathname);
     })
@@ -768,7 +648,7 @@ Module.runMain = function() {
       process.exit(1);
     });
   } else {
-    Module._load(process.argv[1], null, true);
+    Module._load(process.argv[1], undefined, true);
   }
   // Handle any nextTicks added in the first tick of the program
   process._tickCallback();
@@ -777,31 +657,28 @@ Module.runMain = function() {
 Module.createRequireFromPath = (filename) => {
   const m = new Module(filename);
   m.filename = filename;
-  m.paths = Module._nodeModulePaths(path.dirname(filename));
+  m.paths = getNodeModulePaths(m.path);
   return makeRequireFunction(m);
 };
 
 Module._initPaths = function() {
-  var homeDir;
-  var nodePath;
+  let homeDir;
+  let nodePath;
+  // $PREFIX/lib/node, where $PREFIX is the root of the Node.js installation.
+  // `process.execPath` is $PREFIX/bin/node except on Windows where it is
+  // $PREFIX\node.exe.
+  let prefixDir;
   if (isWindows) {
     homeDir = process.env.USERPROFILE;
     nodePath = process.env.NODE_PATH;
+    prefixDir = path.resolve(process.execPath, '..');
   } else {
     homeDir = safeGetenv('HOME');
     nodePath = safeGetenv('NODE_PATH');
-  }
-
-  // $PREFIX/lib/node, where $PREFIX is the root of the Node.js installation.
-  var prefixDir;
-  // process.execPath is $PREFIX/bin/node except on Windows where it is
-  // $PREFIX\node.exe.
-  if (isWindows) {
-    prefixDir = path.resolve(process.execPath, '..');
-  } else {
     prefixDir = path.resolve(process.execPath, '..', '..');
   }
-  var paths = [path.resolve(prefixDir, 'lib', 'node')];
+
+  let paths = [path.resolve(prefixDir, 'lib', 'node')];
 
   if (homeDir) {
     paths.unshift(path.resolve(homeDir, '.node_libraries'));
@@ -809,37 +686,144 @@ Module._initPaths = function() {
   }
 
   if (nodePath) {
-    paths = nodePath.split(path.delimiter).filter(function pathsFilterCB(path) {
-      return !!path;
-    }).concat(paths);
+    paths = nodePath.split(path.delimiter)
+                    .filter((path) => !!path)
+                    .concat(paths);
   }
 
-  modulePaths = paths;
+  // Filter all paths that do not exist or that resolve to a file instead of a
+  // directory.
+  modulePaths = paths.filter((path) => stat(path) === 1);
 
-  // clone as a shallow copy, for introspection.
-  Module.globalPaths = modulePaths.slice(0);
+  // Use the original input for introspection.
+  Module.globalPaths = paths;
 };
 
 Module._preloadModules = function(requests) {
-  if (!Array.isArray(requests))
-    return;
-
   // Preloaded modules have a dummy parent module which is deemed to exist
   // in the current working directory. This seeds the search path for
   // preloaded modules.
-  var parent = new Module('internal/preload', null);
+  const parent = new Module('internal/preload');
   try {
-    parent.paths = Module._nodeModulePaths(process.cwd());
+    parent.paths = getNodeModulePaths(process.cwd());
   } catch (e) {
     if (e.code !== 'ENOENT') {
       throw e;
     }
+    parent.paths = [];
+  }
+  for (const request of requests) {
+    parent.require(request);
   }
-  for (var n = 0; n < requests.length; n++)
-    parent.require(requests[n]);
 };
 
 Module._initPaths();
 
 // Backwards compatibility
 Module.Module = Module;
+
+const extensions = Object.create(null);
+
+// Native extension for .js
+extensions['.js'] = function(module, filename) {
+  const content = fs.readFileSync(filename, 'utf8');
+  module._compile(stripBOM(content), filename);
+};
+
+// Native extension for .json
+extensions['.json'] = function(module, filename) {
+  const content = fs.readFileSync(filename, 'utf8');
+  try {
+    module.exports = JSON.parse(stripBOM(content));
+  } catch (err) {
+    err.message = `${filename}: ${err.message}`;
+    throw err;
+  }
+};
+
+// Native extension for .node
+extensions['.node'] = function(module, filename) {
+  return process.dlopen(module, path.toNamespacedPath(filename));
+};
+
+if (experimentalModules) {
+  extensions['.mjs'] = function(module, filename) {
+    throw new ERR_REQUIRE_ESM(filename);
+  };
+}
+
+// Use proxies to optimize resetting the extensions. This would otherwise be a
+// significant overhead as we have to check for all object keys each time a
+// uncached module is loaded (everything else would be a breaking change).
+function setExtensionsProxy(extensions) {
+  // Intersect manipulating the extensions.
+  extensionNames = Object.keys(extensions);
+  extensionCopy = Object.create(null);
+  for (const name of extensionNames) {
+    extensionCopy[name] = true;
+  }
+  return new Proxy(extensions, {
+    set(obj, prop, value) {
+      if (typeof prop !== 'symbol' && extensionCopy[prop] === undefined) {
+        extensionCopy[prop] = true;
+        extensionNames.push(prop);
+      }
+      return Reflect.set(obj, prop, value);
+    },
+    defineProperty(target, prop, descriptor) {
+      if (typeof prop !== 'symbol' && extensionCopy[prop] === undefined) {
+        extensionCopy[prop] = true;
+        extensionNames.push(prop);
+      }
+      return Reflect.defineProperty(target, prop, descriptor);
+    },
+    deleteProperty(target, prop) {
+      const pos = extensionNames.indexOf(prop);
+      if (pos !== -1) {
+        delete extensionCopy[prop];
+        extensionNames.splice(pos, 1);
+      }
+      return Reflect.deleteProperty(target, prop);
+    }
+  });
+}
+
+// Intersect manipulating the extensions.
+const ProxyModule = new Proxy(Module, {
+  set(obj, prop, value) {
+    if (prop === '_extensions') {
+      value = setExtensionsProxy(value);
+    }
+    return Reflect.set(obj, prop, value);
+  },
+  defineProperty(target, prop, descriptor) {
+    if (prop === '_extensions') {
+      if (descriptor.value) {
+        descriptor = {
+          ...descriptor,
+          value: setExtensionsProxy(descriptor.value)
+        };
+      } else {
+        descriptor = {
+          ...descriptor,
+          get() {
+            return setExtensionsProxy(descriptor.get());
+          }
+        };
+      }
+    }
+    return Reflect.defineProperty(target, prop, descriptor);
+  }
+});
+
+Module._extensions = setExtensionsProxy(extensions);
+
+module.exports = ProxyModule;
+
+// We have to load the esm things after module.exports!
+if (experimentalModules) {
+  asyncESM = require('internal/process/esm_loader');
+  ModuleJob = require('internal/modules/esm/module_job');
+  createDynamicModule = require(
+    'internal/modules/esm/create_dynamic_module');
+}
diff --git a/lib/repl.js b/lib/repl.js
index 30812c232b7639..c1852ee395e970 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -829,7 +829,7 @@ REPLServer.prototype.createContext = function() {
 
   var module = new CJSModule('<repl>');
   module.paths =
-    CJSModule._resolveLookupPaths('<repl>', parentModule, true) || [];
+    CJSModule._resolveLookupPaths('<repl>', parentModule) || [];
 
   Object.defineProperty(context, 'module', {
     configurable: true,
diff --git a/test/fixtures/module-require-depth/one.js b/test/fixtures/module-require-depth/one.js
deleted file mode 100644
index 02b451465bb76c..00000000000000
--- a/test/fixtures/module-require-depth/one.js
+++ /dev/null
@@ -1,11 +0,0 @@
-// Flags: --expose_internals
-'use strict';
-const assert = require('assert');
-const {
-  requireDepth
-} = require('internal/modules/cjs/helpers');
-
-exports.requireDepth = requireDepth;
-assert.strictEqual(requireDepth, 1);
-assert.deepStrictEqual(require('./two'), { requireDepth: 2 });
-assert.strictEqual(requireDepth, 1);
diff --git a/test/fixtures/module-require-depth/two.js b/test/fixtures/module-require-depth/two.js
deleted file mode 100644
index 5c94c4c89aa9ef..00000000000000
--- a/test/fixtures/module-require-depth/two.js
+++ /dev/null
@@ -1,11 +0,0 @@
-// Flags: --expose_internals
-'use strict';
-const assert = require('assert');
-const {
-  requireDepth
-} = require('internal/modules/cjs/helpers');
-
-exports.requireDepth = requireDepth;
-assert.strictEqual(requireDepth, 2);
-assert.deepStrictEqual(require('./one'), { requireDepth: 1 });
-assert.strictEqual(requireDepth, 2);
diff --git a/test/fixtures/require-resolve.js b/test/fixtures/require-resolve.js
index 2a0dc8846ce3cb..a6a85f354d3b50 100644
--- a/test/fixtures/require-resolve.js
+++ b/test/fixtures/require-resolve.js
@@ -14,8 +14,28 @@ assert.strictEqual(
 
 // Verify that existing paths are removed.
 assert.throws(() => {
-  require.resolve('bar', { paths: [] })
-}, /^Error: Cannot find module 'bar'$/);
+  require.resolve('bar', { paths: ['/zzzzzzz'] })
+}, {
+  name: 'Error',
+  code: 'MODULE_NOT_FOUND',
+  message: "Cannot find module 'bar'"
+});
+
+// Verify invalid paths throw.
+{
+  assert.throws(() => {
+    require.resolve('bar', { paths: [] })
+  }, {
+    name: 'RangeError [ERR_OUT_OF_RANGE]',
+    code: 'ERR_OUT_OF_RANGE'
+  });
+  assert.throws(() => {
+    require.resolve('bar', { paths: '/path' })
+  }, {
+    name: 'TypeError [ERR_INVALID_ARG_TYPE]',
+    code: 'ERR_INVALID_ARG_TYPE'
+  });
+}
 
 // Verify that resolution path can be overwritten.
 {
diff --git a/test/message/assert_throws_stack.out b/test/message/assert_throws_stack.out
index cf96ee42c98cb7..0457670d6a317c 100644
--- a/test/message/assert_throws_stack.out
+++ b/test/message/assert_throws_stack.out
@@ -17,4 +17,3 @@ AssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:
     at *
     at *
     at *
-    at *
diff --git a/test/message/core_line_numbers.out b/test/message/core_line_numbers.out
index 59953132fa0542..0670b24b36382d 100644
--- a/test/message/core_line_numbers.out
+++ b/test/message/core_line_numbers.out
@@ -7,9 +7,9 @@ RangeError: Invalid input
     at Object.decode (punycode.js:*:*)
     at Object.<anonymous> (*test*message*core_line_numbers.js:*:*)
     at Module._compile (internal/modules/cjs/loader.js:*:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
     at executeUserCode (internal/bootstrap/node.js:*:*)
+    at startExecution (internal/bootstrap/node.js:*:*)
diff --git a/test/message/error_exit.out b/test/message/error_exit.out
index 6e9b42167dde18..dcda6def9e51b5 100644
--- a/test/message/error_exit.out
+++ b/test/message/error_exit.out
@@ -9,10 +9,9 @@ AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
 
     at Object.<anonymous> (*test*message*error_exit.js:*:*)
     at Module._compile (internal/modules/cjs/loader.js:*:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
     at executeUserCode (internal/bootstrap/node.js:*:*)
     at startExecution (internal/bootstrap/node.js:*:*)
diff --git a/test/message/events_unhandled_error_common_trace.out b/test/message/events_unhandled_error_common_trace.out
index 67be22554fb41e..3b7535266b96ac 100644
--- a/test/message/events_unhandled_error_common_trace.out
+++ b/test/message/events_unhandled_error_common_trace.out
@@ -7,16 +7,15 @@ Error: foo:bar
     at foo (*events_unhandled_error_common_trace.js:*:*)
     at Object.<anonymous> (*events_unhandled_error_common_trace.js:*:*)
     at Module._compile (internal/modules/cjs/loader.js:*:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
     at executeUserCode (internal/bootstrap/node.js:*:*)
+    at startExecution (internal/bootstrap/node.js:*:*)
 Emitted 'error' event at:
     at quux (*events_unhandled_error_common_trace.js:*:*)
     at Object.<anonymous> (*events_unhandled_error_common_trace.js:*:*)
     at Module._compile (internal/modules/cjs/loader.js:*:*)
     [... lines matching original stack trace ...]
-    at executeUserCode (internal/bootstrap/node.js:*:*)
     at startExecution (internal/bootstrap/node.js:*:*)
diff --git a/test/message/events_unhandled_error_nexttick.out b/test/message/events_unhandled_error_nexttick.out
index cd098b64bfb5f1..5349cc68b3e507 100644
--- a/test/message/events_unhandled_error_nexttick.out
+++ b/test/message/events_unhandled_error_nexttick.out
@@ -5,17 +5,16 @@ events.js:*
 Error
     at Object.<anonymous> (*events_unhandled_error_nexttick.js:*:*)
     at Module._compile (internal/modules/cjs/loader.js:*:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
     at executeUserCode (internal/bootstrap/node.js:*:*)
     at startExecution (internal/bootstrap/node.js:*:*)
 Emitted 'error' event at:
     at process.nextTick (*events_unhandled_error_nexttick.js:*:*)
     at internalTickCallback (internal/process/next_tick.js:*:*)
     at process.runNextTicks [as _tickCallback] (internal/process/next_tick.js:*:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
     at executeUserCode (internal/bootstrap/node.js:*:*)
     at startExecution (internal/bootstrap/node.js:*:*)
diff --git a/test/message/events_unhandled_error_sameline.out b/test/message/events_unhandled_error_sameline.out
index 678a9ae4b11d7d..0286131fdf5e69 100644
--- a/test/message/events_unhandled_error_sameline.out
+++ b/test/message/events_unhandled_error_sameline.out
@@ -5,11 +5,10 @@ events.js:*
 Error
     at Object.<anonymous> (*events_unhandled_error_sameline.js:*:*)
     at Module._compile (internal/modules/cjs/loader.js:*:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
     at executeUserCode (internal/bootstrap/node.js:*:*)
     at startExecution (internal/bootstrap/node.js:*:*)
 Emitted 'error' event at:
diff --git a/test/message/if-error-has-good-stack.out b/test/message/if-error-has-good-stack.out
index 2a4dfe8fb26630..a11e07981e4c6a 100644
--- a/test/message/if-error-has-good-stack.out
+++ b/test/message/if-error-has-good-stack.out
@@ -12,8 +12,8 @@ AssertionError [ERR_ASSERTION]: ifError got unwanted exception: test error
     at a (*if-error-has-good-stack.js:*:*)
     at Object.<anonymous> (*if-error-has-good-stack.js:*:*)
     at Module._compile (internal/modules/cjs/loader.js:*:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at executeUserCode (internal/bootstrap/node.js:*:*)
diff --git a/test/message/nexttick_throw.out b/test/message/nexttick_throw.out
index 6a4d7ed2dabcb0..7228f15bae5a02 100644
--- a/test/message/nexttick_throw.out
+++ b/test/message/nexttick_throw.out
@@ -6,6 +6,6 @@ ReferenceError: undefined_reference_error_maker is not defined
     at *test*message*nexttick_throw.js:*:*
     at internalTickCallback (internal/process/next_tick.js:*:*)
     at process.runNextTicks [as _tickCallback] (internal/process/next_tick.js:*:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
     at executeUserCode (internal/bootstrap/node.js:*:*)
     at startExecution (internal/bootstrap/node.js:*:*)
diff --git a/test/message/undefined_reference_in_new_context.out b/test/message/undefined_reference_in_new_context.out
index 6b5fedfa993701..85ce0de574b673 100644
--- a/test/message/undefined_reference_in_new_context.out
+++ b/test/message/undefined_reference_in_new_context.out
@@ -12,5 +12,5 @@ ReferenceError: foo is not defined
     at Module._compile (internal/modules/cjs/loader.js:*)
     at *..js (internal/modules/cjs/loader.js:*)
     at Module.load (internal/modules/cjs/loader.js:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*:*)
diff --git a/test/message/unhandled_promise_trace_warnings.out b/test/message/unhandled_promise_trace_warnings.out
index 1f88a136a9aa13..77ddea8aa60420 100644
--- a/test/message/unhandled_promise_trace_warnings.out
+++ b/test/message/unhandled_promise_trace_warnings.out
@@ -14,7 +14,6 @@
     at *
     at *
     at *
-    at *
 (node:*) Error: This was rejected
     at * (*test*message*unhandled_promise_trace_warnings.js:*)
     at *
@@ -24,7 +23,6 @@
     at *
     at *
     at *
-    at *
 (node:*) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
     at *
     at *
diff --git a/test/message/util_inspect_error.out b/test/message/util_inspect_error.out
index 406d8112ce2599..e5044bd75e8b97 100644
--- a/test/message/util_inspect_error.out
+++ b/test/message/util_inspect_error.out
@@ -9,7 +9,6 @@
        at *
        at *
        at *
-       at *
   nested:
    { err:
       Error: foo
@@ -21,7 +20,6 @@
           at *
           at *
           at *
-          at *
           at * } }
 {
   err: Error: foo
@@ -33,7 +31,6 @@
       at *
       at *
       at *
-      at *
       at *,
   nested: {
     err: Error: foo
@@ -46,7 +43,6 @@
         at *
         at *
         at *
-        at *
   }
 }
 { Error: foo
@@ -59,5 +55,4 @@ bar
     at *
     at *
     at *
-    at *
   foo: 'bar' }
diff --git a/test/message/vm_display_runtime_error.out b/test/message/vm_display_runtime_error.out
index bc95b2a7b092f5..6079d01af5f4c9 100644
--- a/test/message/vm_display_runtime_error.out
+++ b/test/message/vm_display_runtime_error.out
@@ -9,11 +9,11 @@ Error: boo!
     at Object.runInThisContext (vm.js:*)
     at Object.<anonymous> (*test*message*vm_display_runtime_error.js:*)
     at Module._compile (internal/modules/cjs/loader.js:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*)
+    at executeUserCode (internal/bootstrap/node.js:*:*)
 test.vm:1
 throw new Error("spooky!")
 ^
@@ -24,8 +24,8 @@ Error: spooky!
     at Object.runInThisContext (vm.js:*)
     at Object.<anonymous> (*test*message*vm_display_runtime_error.js:*)
     at Module._compile (internal/modules/cjs/loader.js:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*)
+    at executeUserCode (internal/bootstrap/node.js:*:*)
diff --git a/test/message/vm_display_syntax_error.out b/test/message/vm_display_syntax_error.out
index f0692723e81257..50a00d37c9dd33 100644
--- a/test/message/vm_display_syntax_error.out
+++ b/test/message/vm_display_syntax_error.out
@@ -8,11 +8,11 @@ SyntaxError: Unexpected number
     at Object.runInThisContext (vm.js:*)
     at Object.<anonymous> (*test*message*vm_display_syntax_error.js:*)
     at Module._compile (internal/modules/cjs/loader.js:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*)
+    at executeUserCode (internal/bootstrap/node.js:*:*)
 test.vm:1
 var 5;
     ^
@@ -22,8 +22,8 @@ SyntaxError: Unexpected number
     at Object.runInThisContext (vm.js:*)
     at Object.<anonymous> (*test*message*vm_display_syntax_error.js:*)
     at Module._compile (internal/modules/cjs/loader.js:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*)
+    at executeUserCode (internal/bootstrap/node.js:*:*)
diff --git a/test/message/vm_dont_display_runtime_error.out b/test/message/vm_dont_display_runtime_error.out
index 532cfbf4dd8125..daeb367376d3b6 100644
--- a/test/message/vm_dont_display_runtime_error.out
+++ b/test/message/vm_dont_display_runtime_error.out
@@ -10,8 +10,8 @@ Error: boo!
     at Object.runInThisContext (vm.js:*)
     at Object.<anonymous> (*test*message*vm_dont_display_runtime_error.js:*)
     at Module._compile (internal/modules/cjs/loader.js:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*)
+    at executeUserCode (internal/bootstrap/node.js:*:*)
diff --git a/test/message/vm_dont_display_syntax_error.out b/test/message/vm_dont_display_syntax_error.out
index f27cb1a0859d8c..31328218f9b02e 100644
--- a/test/message/vm_dont_display_syntax_error.out
+++ b/test/message/vm_dont_display_syntax_error.out
@@ -10,8 +10,8 @@ SyntaxError: Unexpected number
     at Object.runInThisContext (vm.js:*)
     at Object.<anonymous> (*test*message*vm_dont_display_syntax_error.js:*)
     at Module._compile (internal/modules/cjs/loader.js:*)
-    at Object.Module._extensions..js (internal/modules/cjs/loader.js:*)
+    at Proxy.extensions..js (internal/modules/cjs/loader.js:*:*)
     at Module.load (internal/modules/cjs/loader.js:*)
-    at tryModuleLoad (internal/modules/cjs/loader.js:*:*)
     at Function.Module._load (internal/modules/cjs/loader.js:*)
-    at Function.Module.runMain (internal/modules/cjs/loader.js:*)
+    at Proxy.Module.runMain (internal/modules/cjs/loader.js:*)
+    at executeUserCode (internal/bootstrap/node.js:*:*)
diff --git a/test/parallel/test-module-multi-extensions.js b/test/parallel/test-module-multi-extensions.js
index be17bc5d025508..be55bc666b55ea 100644
--- a/test/parallel/test-module-multi-extensions.js
+++ b/test/parallel/test-module-multi-extensions.js
@@ -18,6 +18,8 @@ fs.writeFileSync(dotfile, 'console.log(__filename);', 'utf8');
 fs.writeFileSync(dotfileWithExtension, 'console.log(__filename);', 'utf8');
 
 {
+  // The Symbol should be ignored.
+  require.extensions[Symbol()] = common.mustNotCall();
   require.extensions['.bar'] = common.mustNotCall();
   require.extensions['.foo.bar'] = common.mustCall();
   const modulePath = path.join(tmpdir.path, 'test-extensions');
diff --git a/test/parallel/test-module-relative-lookup.js b/test/parallel/test-module-relative-lookup.js
index c5350e11facda4..045fdc49b51863 100644
--- a/test/parallel/test-module-relative-lookup.js
+++ b/test/parallel/test-module-relative-lookup.js
@@ -10,12 +10,11 @@ function testFirstInPath(moduleName, isLocalModule) {
     assert.strictEqual :
     assert.notStrictEqual;
 
-  const lookupResults = _module._resolveLookupPaths(moduleName);
+  let paths = _module._resolveLookupPaths(moduleName);
 
-  let paths = lookupResults[1];
   assertFunction(paths[0], '.');
 
-  paths = _module._resolveLookupPaths(moduleName, null, true);
+  paths = _module._resolveLookupPaths(moduleName, null);
   assertFunction(paths && paths[0], '.');
 }
 
diff --git a/test/parallel/test-module-require-depth.js b/test/parallel/test-module-require-depth.js
deleted file mode 100644
index 0a3fc2826c71f4..00000000000000
--- a/test/parallel/test-module-require-depth.js
+++ /dev/null
@@ -1,16 +0,0 @@
-// Flags: --expose_internals
-'use strict';
-require('../common');
-const fixtures = require('../common/fixtures');
-const assert = require('assert');
-const {
-  requireDepth
-} = require('internal/modules/cjs/helpers');
-
-// Module one loads two too so the expected depth for two is, well, two.
-assert.strictEqual(requireDepth, 0);
-const one = require(fixtures.path('module-require-depth', 'one'));
-const two = require(fixtures.path('module-require-depth', 'two'));
-assert.deepStrictEqual(one, { requireDepth: 1 });
-assert.deepStrictEqual(two, { requireDepth: 2 });
-assert.strictEqual(requireDepth, 0);
diff --git a/test/parallel/test-repl.js b/test/parallel/test-repl.js
index 89370b0f7ad464..415d3325b7814f 100644
--- a/test/parallel/test-repl.js
+++ b/test/parallel/test-repl.js
@@ -536,6 +536,7 @@ const errorTests = [
       /^    at .*/,
       /^    at .*/,
       /^    at .*/,
+      /^    at .*/,
       /^    at .*/
     ]
   },
diff --git a/test/parallel/test-require-dot.js b/test/parallel/test-require-dot.js
index 423441cfcde435..42a59487e90295 100644
--- a/test/parallel/test-require-dot.js
+++ b/test/parallel/test-require-dot.js
@@ -14,9 +14,10 @@ assert.strictEqual(a, b);
 process.env.NODE_PATH = fixtures.path('module-require', 'relative');
 m._initPaths();
 
-const c = require('.');
-assert.strictEqual(
-  c.value,
-  42,
-  `require(".") should honor NODE_PATH; expected 42, found ${c.value}`
+assert.throws(
+  () => require('.'),
+  {
+    message: "Cannot find module '.'",
+    code: 'MODULE_NOT_FOUND'
+  }
 );