diff --git a/.eslintrc.js b/.eslintrc.js
index 477b21dba..b7b50beca 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -35,7 +35,6 @@ module.exports = {
 				"prop": "property",
 				"memberof": "DONTUSE",
 				"class": "DONTUSE",
-				"extends": "DONTUSE",
 				"inheritdoc": "DONTUSE",
 				"description": "DONTUSE",
 				"readonly": "DONTUSE"
diff --git a/lib/Chunk.js b/lib/Chunk.js
index 7d9ad3a05..95d3588f0 100644
--- a/lib/Chunk.js
+++ b/lib/Chunk.js
@@ -15,6 +15,7 @@ const ERR_CHUNK_INITIAL =
 
 /** @typedef {import("./Module.js")} Module */
 /** @typedef {import("./ChunkGroup")} ChunkGroup */
+/** @typedef {import("./Entrypoint")} Entrypoint */
 /** @typedef {import("./ModuleReason.js")} ModuleReason */
 /** @typedef {import("webpack-sources").Source} Source */
 /** @typedef {import("./util/createHash").Hash} Hash */
@@ -126,7 +127,7 @@ class Chunk {
 
 		/** @private */
 		this._groups = new SortableSet(undefined, sortChunkGroupById);
-		/** @private @type {SortableSet<ChunkGroup>} */
+		/** @private @type {SortableSet<ChunkGroup | Entrypoint>} */
 		this._groups = new SortableSet(undefined, sortChunkGroupById);
 		/** @type {string[]} */
 		this.files = [];
@@ -185,7 +186,11 @@ class Chunk {
 	hasRuntime() {
 		for (const chunkGroup of this._groups) {
 			// We only need to check the first one
-			return chunkGroup.isInitial() && chunkGroup.getRuntimeChunk() === this;
+			return (
+				chunkGroup.isInitial() &&
+				// prettier-ignore
+				/** @type {Entrypoint} */ (chunkGroup).getRuntimeChunk() === this
+			);
 		}
 		return false;
 	}
@@ -749,17 +754,37 @@ class Chunk {
 // TODO remove in webpack 5
 Object.defineProperty(Chunk.prototype, "forEachModule", {
 	configurable: false,
-	value: util.deprecate(function(fn) {
-		this._modules.forEach(fn);
-	}, "Chunk.forEachModule: Use for(const module of chunk.modulesIterable) instead")
+	value: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {Chunk}
+		 * @typedef {function(any, any, Set<any>): void} ForEachModuleCallback
+		 * @param {ForEachModuleCallback} fn Callback function
+		 * @returns {void}
+		 */
+		function(fn) {
+			this._modules.forEach(fn);
+		},
+		"Chunk.forEachModule: Use for(const module of chunk.modulesIterable) instead"
+	)
 });
 
 // TODO remove in webpack 5
 Object.defineProperty(Chunk.prototype, "mapModules", {
 	configurable: false,
-	value: util.deprecate(function(fn) {
-		return Array.from(this._modules, fn);
-	}, "Chunk.mapModules: Use Array.from(chunk.modulesIterable, fn) instead")
+	value: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {Chunk}
+		 * @typedef {function(any, number): any} MapModulesCallback
+		 * @param {MapModulesCallback} fn Callback function
+		 * @returns {TODO[]} result of mapped modules
+		 */
+		function(fn) {
+			return Array.from(this._modules, fn);
+		},
+		"Chunk.mapModules: Use Array.from(chunk.modulesIterable, fn) instead"
+	)
 });
 
 // TODO remove in webpack 5
diff --git a/lib/ChunkGroup.js b/lib/ChunkGroup.js
index 19e8f3c67..4acbc46c3 100644
--- a/lib/ChunkGroup.js
+++ b/lib/ChunkGroup.js
@@ -11,7 +11,6 @@ const compareLocations = require("./compareLocations");
 /** @typedef {import("./Module")} Module */
 /** @typedef {import("./ModuleReason")} ModuleReason */
 
-/** @typedef {{id: number}} HasId */
 /** @typedef {{module: Module, loc: TODO, request: string}} OriginRecord */
 /** @typedef {string|{name: string}} ChunkGroupOptions */
 
@@ -26,8 +25,8 @@ const getArray = set => Array.from(set);
 
 /**
  * A convenience method used to sort chunks based on their id's
- * @param {HasId} a first sorting comparator
- * @param {HasId} b second sorting comparator
+ * @param {ChunkGroup} a first sorting comparator
+ * @param {ChunkGroup} b second sorting comparator
  * @returns {1|0|-1} a sorting index to determine order
  */
 const sortById = (a, b) => {
@@ -63,6 +62,7 @@ class ChunkGroup {
 		/** @type {number} */
 		this.groupDebugId = debugId++;
 		this.options = options;
+		/** @type {SortableSet<ChunkGroup>} */
 		this._children = new SortableSet(undefined, sortById);
 		this._parents = new SortableSet(undefined, sortById);
 		this._blocks = new SortableSet();
diff --git a/lib/Compilation.js b/lib/Compilation.js
index c1be909f1..1008ee3e9 100644
--- a/lib/Compilation.js
+++ b/lib/Compilation.js
@@ -2438,21 +2438,48 @@ class Compilation extends Tapable {
 }
 
 // TODO remove in webpack 5
-Compilation.prototype.applyPlugins = util.deprecate(function(name, ...args) {
-	this.hooks[
-		name.replace(/[- ]([a-z])/g, match => match[1].toUpperCase())
-	].call(...args);
-}, "Compilation.applyPlugins is deprecated. Use new API on `.hooks` instead");
+Compilation.prototype.applyPlugins = util.deprecate(
+	/**
+	 * @deprecated
+	 * @param {string} name Name
+	 * @param {any[]} args Other arguments
+	 * @returns {void}
+	 * @this {Compilation}
+	 */
+	function(name, ...args) {
+		this.hooks[
+			name.replace(/[- ]([a-z])/g, match => match[1].toUpperCase())
+		].call(...args);
+	},
+	"Compilation.applyPlugins is deprecated. Use new API on `.hooks` instead"
+);
 
 // TODO remove in webpack 5
 Object.defineProperty(Compilation.prototype, "moduleTemplate", {
 	configurable: false,
-	get: util.deprecate(function() {
-		return this.moduleTemplates.javascript;
-	}, "Compilation.moduleTemplate: Use Compilation.moduleTemplates.javascript instead"),
-	set: util.deprecate(function(value) {
-		this.moduleTemplates.javascript = value;
-	}, "Compilation.moduleTemplate: Use Compilation.moduleTemplates.javascript instead.")
+	get: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {Compilation}
+		 * @returns {TODO} module template
+		 */
+		function() {
+			return this.moduleTemplates.javascript;
+		},
+		"Compilation.moduleTemplate: Use Compilation.moduleTemplates.javascript instead"
+	),
+	set: util.deprecate(
+		/**
+		 * @deprecated
+		 * @param {ModuleTemplate} value Template value
+		 * @this {Compilation}
+		 * @returns {void}
+		 */
+		function(value) {
+			this.moduleTemplates.javascript = value;
+		},
+		"Compilation.moduleTemplate: Use Compilation.moduleTemplates.javascript instead."
+	)
 });
 
 module.exports = Compilation;
diff --git a/lib/ContextModule.js b/lib/ContextModule.js
index 9db2914b7..dbf197ecc 100644
--- a/lib/ContextModule.js
+++ b/lib/ContextModule.js
@@ -10,6 +10,7 @@ const AsyncDependenciesBlock = require("./AsyncDependenciesBlock");
 const Template = require("./Template");
 const contextify = require("./util/identifier").contextify;
 
+/** @typedef {"sync" | "eager" | "weak" | "async-weak" | "lazy" | "lazy-once"} ContextMode Context mode */
 /** @typedef {import("./dependencies/ContextElementDependency")} ContextElementDependency */
 
 class ContextModule extends Module {
@@ -684,56 +685,141 @@ webpackEmptyAsyncContext.id = ${JSON.stringify(id)};`;
 // TODO remove in webpack 5
 Object.defineProperty(ContextModule.prototype, "recursive", {
 	configurable: false,
-	get: util.deprecate(function() {
-		return this.options.recursive;
-	}, "ContextModule.recursive has been moved to ContextModule.options.recursive"),
-	set: util.deprecate(function(value) {
-		this.options.recursive = value;
-	}, "ContextModule.recursive has been moved to ContextModule.options.recursive")
+	get: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @returns {boolean} is recursive
+		 */
+		function() {
+			return this.options.recursive;
+		},
+		"ContextModule.recursive has been moved to ContextModule.options.recursive"
+	),
+	set: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @param {boolean} value is recursive
+		 * @returns {void}
+		 */
+		function(value) {
+			this.options.recursive = value;
+		},
+		"ContextModule.recursive has been moved to ContextModule.options.recursive"
+	)
 });
 
 // TODO remove in webpack 5
 Object.defineProperty(ContextModule.prototype, "regExp", {
 	configurable: false,
-	get: util.deprecate(function() {
-		return this.options.regExp;
-	}, "ContextModule.regExp has been moved to ContextModule.options.regExp"),
-	set: util.deprecate(function(value) {
-		this.options.regExp = value;
-	}, "ContextModule.regExp has been moved to ContextModule.options.regExp")
+	get: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @returns {RegExp} regular expression
+		 */
+		function() {
+			return this.options.regExp;
+		},
+		"ContextModule.regExp has been moved to ContextModule.options.regExp"
+	),
+	set: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @param {RegExp} value Regular expression
+		 * @returns {void}
+		 */
+		function(value) {
+			this.options.regExp = value;
+		},
+		"ContextModule.regExp has been moved to ContextModule.options.regExp"
+	)
 });
 
 // TODO remove in webpack 5
 Object.defineProperty(ContextModule.prototype, "addon", {
 	configurable: false,
-	get: util.deprecate(function() {
-		return this.options.addon;
-	}, "ContextModule.addon has been moved to ContextModule.options.addon"),
-	set: util.deprecate(function(value) {
-		this.options.addon = value;
-	}, "ContextModule.addon has been moved to ContextModule.options.addon")
+	get: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @returns {string} addon
+		 */
+		function() {
+			return this.options.addon;
+		},
+		"ContextModule.addon has been moved to ContextModule.options.addon"
+	),
+	set: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @param {string} value addon
+		 * @returns {void}
+		 */
+		function(value) {
+			this.options.addon = value;
+		},
+		"ContextModule.addon has been moved to ContextModule.options.addon"
+	)
 });
 
 // TODO remove in webpack 5
 Object.defineProperty(ContextModule.prototype, "async", {
 	configurable: false,
-	get: util.deprecate(function() {
-		return this.options.mode;
-	}, "ContextModule.async has been moved to ContextModule.options.mode"),
-	set: util.deprecate(function(value) {
-		this.options.mode = value;
-	}, "ContextModule.async has been moved to ContextModule.options.mode")
+	get: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @returns {boolean} is async
+		 */
+		function() {
+			return this.options.mode;
+		},
+		"ContextModule.async has been moved to ContextModule.options.mode"
+	),
+	set: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @param {ContextMode} value Context mode
+		 * @returns {void}
+		 */
+		function(value) {
+			this.options.mode = value;
+		},
+		"ContextModule.async has been moved to ContextModule.options.mode"
+	)
 });
 
 // TODO remove in webpack 5
 Object.defineProperty(ContextModule.prototype, "chunkName", {
 	configurable: false,
-	get: util.deprecate(function() {
-		return this.options.chunkName;
-	}, "ContextModule.chunkName has been moved to ContextModule.options.chunkName"),
-	set: util.deprecate(function(value) {
-		this.options.chunkName = value;
-	}, "ContextModule.chunkName has been moved to ContextModule.options.chunkName")
+	get: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @returns {string} chunk name
+		 */
+		function() {
+			return this.options.chunkName;
+		},
+		"ContextModule.chunkName has been moved to ContextModule.options.chunkName"
+	),
+	set: util.deprecate(
+		/**
+		 * @deprecated
+		 * @this {ContextModule}
+		 * @param {string} value chunk name
+		 * @returns {void}
+		 */
+		function(value) {
+			this.options.chunkName = value;
+		},
+		"ContextModule.chunkName has been moved to ContextModule.options.chunkName"
+	)
 });
 
 module.exports = ContextModule;
diff --git a/lib/Module.js b/lib/Module.js
index b0a533a85..6af441559 100644
--- a/lib/Module.js
+++ b/lib/Module.js
@@ -339,17 +339,35 @@ class Module extends DependenciesBlock {
 // TODO remove in webpack 5
 Object.defineProperty(Module.prototype, "forEachChunk", {
 	configurable: false,
-	value: util.deprecate(function(fn) {
-		this._chunks.forEach(fn);
-	}, "Module.forEachChunk: Use for(const chunk of module.chunksIterable) instead")
+	value: util.deprecate(
+		/**
+		 * @deprecated
+		 * @param {function(any, any, Set<any>): void} fn callback function
+		 * @returns {void}
+		 * @this {Module}
+		 */
+		function(fn) {
+			this._chunks.forEach(fn);
+		},
+		"Module.forEachChunk: Use for(const chunk of module.chunksIterable) instead"
+	)
 });
 
 // TODO remove in webpack 5
 Object.defineProperty(Module.prototype, "mapChunks", {
 	configurable: false,
-	value: util.deprecate(function(fn) {
-		return Array.from(this._chunks, fn);
-	}, "Module.mapChunks: Use Array.from(module.chunksIterable, fn) instead")
+	value: util.deprecate(
+		/**
+		 * @deprecated
+		 * @param {function(any, any): void} fn Mapper function
+		 * @returns {Array<TODO>} Array of chunks mapped
+		 * @this {Module}
+		 */
+		function(fn) {
+			return Array.from(this._chunks, fn);
+		},
+		"Module.mapChunks: Use Array.from(module.chunksIterable, fn) instead"
+	)
 });
 
 // TODO remove in webpack 5
@@ -366,12 +384,29 @@ Object.defineProperty(Module.prototype, "entry", {
 // TODO remove in webpack 5
 Object.defineProperty(Module.prototype, "meta", {
 	configurable: false,
-	get: util.deprecate(function() {
-		return this.buildMeta;
-	}, "Module.meta was renamed to Module.buildMeta"),
-	set: util.deprecate(function(value) {
-		this.buildMeta = value;
-	}, "Module.meta was renamed to Module.buildMeta")
+	get: util.deprecate(
+		/**
+		 * @deprecated
+		 * @returns {void}
+		 * @this {Module}
+		 */
+		function() {
+			return this.buildMeta;
+		},
+		"Module.meta was renamed to Module.buildMeta"
+	),
+	set: util.deprecate(
+		/**
+		 * @deprecated
+		 * @param {TODO} value Value
+		 * @returns {void}
+		 * @this {Module}
+		 */
+		function(value) {
+			this.buildMeta = value;
+		},
+		"Module.meta was renamed to Module.buildMeta"
+	)
 });
 
 /** @type {function(): string} */
diff --git a/lib/Parser.js b/lib/Parser.js
index 515df3877..787f67d61 100644
--- a/lib/Parser.js
+++ b/lib/Parser.js
@@ -2185,9 +2185,18 @@ class Parser extends Tapable {
 // TODO remove in webpack 5
 Object.defineProperty(Parser.prototype, "getCommentOptions", {
 	configurable: false,
-	value: util.deprecate(function(range) {
-		return this.parseCommentOptions(range).options;
-	}, "Parser.getCommentOptions: Use Parser.parseCommentOptions(range) instead")
+	value: util.deprecate(
+		/**
+		 * @deprecated
+		 * @param {TODO} range Range
+		 * @returns {void}
+		 * @this {Parser}
+		 */
+		function(range) {
+			return this.parseCommentOptions(range).options;
+		},
+		"Parser.getCommentOptions: Use Parser.parseCommentOptions(range) instead"
+	)
 });
 
 module.exports = Parser;
diff --git a/lib/util/SortableSet.js b/lib/util/SortableSet.js
index f391f07d0..44b692f37 100644
--- a/lib/util/SortableSet.js
+++ b/lib/util/SortableSet.js
@@ -3,6 +3,7 @@
 /**
  * A subset of Set that offers sorting functionality
  * @template T item type in set
+ * @extends {Set<T>}
  */
 class SortableSet extends Set {
 	/**
diff --git a/lib/util/StackedSetMap.js b/lib/util/StackedSetMap.js
index 589b68d52..fcf628b0d 100644
--- a/lib/util/StackedSetMap.js
+++ b/lib/util/StackedSetMap.js
@@ -128,8 +128,17 @@ class StackedSetMap {
 }
 
 // TODO remove in webpack 5
-StackedSetMap.prototype.push = util.deprecate(function(item) {
-	this.add(item);
-}, "This is no longer an Array: Use add instead.");
+StackedSetMap.prototype.push = util.deprecate(
+	/**
+	 * @deprecated
+	 * @this {StackedSetMap}
+	 * @param {any} item Item to add
+	 * @returns {void}
+	 */
+	function(item) {
+		this.add(item);
+	},
+	"This is no longer an Array: Use add instead."
+);
 
 module.exports = StackedSetMap;
diff --git a/lib/webpack.js b/lib/webpack.js
index f5a8af68f..a8e474605 100644
--- a/lib/webpack.js
+++ b/lib/webpack.js
@@ -69,6 +69,7 @@ webpack.WebpackOptionsApply = WebpackOptionsApply;
 webpack.Compiler = Compiler;
 webpack.MultiCompiler = MultiCompiler;
 webpack.NodeEnvironmentPlugin = NodeEnvironmentPlugin;
+// @ts-ignore Global @this directive is not supported
 webpack.validate = validateSchema.bind(this, webpackOptionsSchema);
 webpack.validateSchema = validateSchema;
 webpack.WebpackOptionsValidationError = WebpackOptionsValidationError;
diff --git a/package.json b/package.json
index a22497fff..d4fbe036b 100644
--- a/package.json
+++ b/package.json
@@ -73,7 +73,7 @@
     "script-loader": "~0.7.0",
     "simple-git": "^1.65.0",
     "style-loader": "^0.19.1",
-    "typescript": "^2.9.1",
+    "typescript": "^3.0.0-dev.20180628",
     "url-loader": "^0.6.2",
     "val-loader": "^1.0.2",
     "vm-browserify": "~0.0.0",
diff --git a/tsconfig.json b/tsconfig.json
index ab2f8191e..b4a8a3be5 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -7,6 +7,7 @@
 		"checkJs": true,
 		"noEmit": true,
 		"strict": false,
+		"noImplicitThis": true,
 		"alwaysStrict": true,
 		"types": ["node"],
 		"esModuleInterop": true
diff --git a/yarn.lock b/yarn.lock
index 037df12f4..9f4adfa45 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5130,8 +5130,8 @@ preserve@^0.2.0:
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
 
 prettier@^1.13.5:
-  version "1.13.5"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.13.5.tgz#7ae2076998c8edce79d63834e9b7b09fead6bfd0"
+  version "1.13.7"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.13.7.tgz#850f3b8af784a49a6ea2d2eaa7ed1428a34b7281"
 
 pretty-format@^22.4.3:
   version "22.4.3"
@@ -6502,9 +6502,9 @@ typedarray@^0.0.6:
   version "0.0.6"
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
 
-typescript@^2.9.1:
-  version "2.9.2"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.9.2.tgz#1cbf61d05d6b96269244eb6a3bce4bd914e0f00c"
+typescript@^3.0.0-dev.20180628:
+  version "3.0.0-dev.20180628"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.0.0-dev.20180628.tgz#9f70006d4e04daa5bb7a8b9db96e3728683330a6"
 
 ua-parser-js@^0.7.9:
   version "0.7.18"