Refactor to track nested exports

Harmony dependencies track access to nested properties
Flag nested exports

lib/Dependency.js

@@ -34,9 +34,16 @@ const DependencyReference = require("./dependencies/DependencyReference");
 
 /** @typedef {SynteticDependencyLocation|RealDependencyLocation} DependencyLocation */
 
+/**
+ * @typedef {Object} ExportSpec
+ * @property {string} name the name of the export
+ * @property {Module=} from  when reexported: from which module
+ * @property {string[] | null=} export  when reexported: from which export
+ */
+
 /**
  * @typedef {Object} ExportsSpec
- * @property {string[] | true | null} exports exported names, true for unknown exports or null for no exports
+ * @property {(string | ExportSpec)[] | true | null} exports exported names, true for unknown exports or null for no exports
  * @property {Module[]=} dependencies module on which the result depends on
  */
 

lib/FlagDependencyExportsPlugin.js

@@ -12,6 +12,7 @@ const Queue = require("./util/Queue");
 /** @typedef {import("./DependenciesBlock")} DependenciesBlock */
 /** @typedef {import("./Dependency")} Dependency */
 /** @typedef {import("./Module")} Module */
+/** @typedef {import("./ModuleGraph").ExportsInfo} ExportsInfo */
 
 const getCacheIdentifier = (compilation, module) => {
 	return `${
@@ -79,6 +80,7 @@ class FlagDependencyExportsPlugin {
 								/** @type {Module} */
 								let module;
 
+								/** @type {ExportsInfo} */
 								let exportsInfo;
 
 								let cacheable = true;
@@ -113,11 +115,35 @@ class FlagDependencyExportsPlugin {
 										}
 									} else if (Array.isArray(exports)) {
 										// merge in new exports
-										for (const exportName of exports) {
+										for (const exportNameOrSpec of exports) {
-											const exportInfo = exportsInfo.getExportInfo(exportName);
+											if (typeof exportNameOrSpec === "string") {
-											if (exportInfo.provided === false) {
+												const exportInfo = exportsInfo.getExportInfo(
-												exportInfo.provided = true;
+													exportNameOrSpec
-												changed = true;
+												);
+												if (exportInfo.provided === false) {
+													exportInfo.provided = true;
+													changed = true;
+												}
+											} else {
+												const exportInfo = exportsInfo.getExportInfo(
+													exportNameOrSpec.name
+												);
+												if (exportInfo.provided === false) {
+													exportInfo.provided = true;
+													changed = true;
+												}
+												if (exportNameOrSpec.from) {
+													const fromExportsInfo = moduleGraph.getExportsInfo(
+														exportNameOrSpec.from
+													);
+													const nestedExportsInfo = fromExportsInfo.getNestedExportsInfo(
+														exportNameOrSpec.export
+													);
+													if (exportInfo.exportsInfo !== nestedExportsInfo) {
+														exportInfo.exportsInfo = nestedExportsInfo;
+														changed = true;
+													}
+												}
 											}
 										}
 									}

lib/FlagDependencyUsagePlugin.js

@@ -5,6 +5,7 @@
 
 "use strict";
 
+const { UsageState } = require("./ModuleGraph");
 const { STAGE_DEFAULT } = require("./OptimizationStages");
 const Queue = require("./util/Queue");
 
@@ -12,6 +13,10 @@ const Queue = require("./util/Queue");
 /** @typedef {import("./DependenciesBlock")} DependenciesBlock */
 /** @typedef {import("./Dependency")} Dependency */
 /** @typedef {import("./Module")} Module */
+/** @typedef {import("./ModuleGraph").ExportsInfo} ExportsInfo */
+
+const NS_OBJ_USED = [[]];
+const NOTHING_USED = [];
 
 class FlagDependencyUsagePlugin {
 	/**
@@ -27,31 +32,60 @@ class FlagDependencyUsagePlugin {
 					stage: STAGE_DEFAULT
 				},
 				modules => {
+					/** @type {Map<ExportsInfo, Module>} */
+					const exportInfoToModuleMap = new Map();
+
 					/**
-					 *
+					 * @typedef {string[]} StringArray
 					 * @param {Module} module module to process
-					 * @param {boolean | string[]} usedExports list of used exports
+					 * @param {StringArray[]} usedExports list of used exports
 					 * @returns {void}
 					 */
 					const processModule = (module, usedExports) => {
 						const exportsInfo = moduleGraph.getExportsInfo(module);
-						let changed = false;
+						if (usedExports.length > 0) {
-						if (usedExports === true) {
+							for (const usedExport of usedExports) {
-							changed = exportsInfo.setUsedInUnknownWay();
+								if (usedExport.length === 0) {
-						} else if (usedExports) {
+									if (exportsInfo.setUsedInUnknownWay()) {
-							for (const exportName of usedExports) {
+										queue.enqueue(module);
-								if (
-									exportName === "default" &&
-									module.buildMeta.exportsType === "named"
-								) {
-									if (exportsInfo.setUsedAsNamedExportType()) {
-										changed = true;
 									}
 								} else {
-									const exportInfo = exportsInfo.getExportInfo(exportName);
+									if (
-									if (exportInfo.used !== true) {
+										usedExport[0] === "default" &&
-										exportInfo.used = true;
+										module.buildMeta.exportsType === "named"
-										changed = true;
+									) {
+										if (exportsInfo.setUsedAsNamedExportType()) {
+											queue.enqueue(module);
+										}
+									} else {
+										let currentExportsInfo = exportsInfo;
+										let currentModule = module;
+										for (let i = 0; i < usedExport.length; i++) {
+											const exportName = usedExport[i];
+											const exportInfo = currentExportsInfo.getExportInfo(
+												exportName
+											);
+											const lastOne = i === usedExport.length - 1;
+											const nestedInfo = exportInfo.exportsInfo;
+											if (!nestedInfo || lastOne) {
+												if (exportInfo.used !== UsageState.Used) {
+													exportInfo.used = UsageState.Used;
+													if (currentModule) {
+														queue.enqueue(currentModule);
+													}
+												}
+												break;
+											} else {
+												if (exportInfo.used === UsageState.Unused) {
+													exportInfo.used = UsageState.OnlyPropertiesUsed;
+													if (currentModule) {
+														queue.enqueue(currentModule);
+													}
+												}
+												currentExportsInfo = nestedInfo;
+												currentModule = exportInfoToModuleMap.get(nestedInfo);
+											}
+										}
 									}
 								}
 							}
@@ -59,11 +93,9 @@ class FlagDependencyUsagePlugin {
 							// for a module without side effects we stop tracking usage here when no export is used
 							// This module won't be evaluated in this case
 							if (module.factoryMeta.sideEffectFree) return;
-							changed = exportsInfo.setUsedForSideEffectsOnly();
+							if (exportsInfo.setUsedForSideEffectsOnly()) {
-						}
+								queue.enqueue(module);
-
+							}
-						if (changed) {
-							queue.enqueue(module);
 						}
 					};
 
@@ -89,11 +121,21 @@ class FlagDependencyUsagePlugin {
 						if (!reference) return;
 						const referenceModule = reference.module;
 						const importedNames = reference.importedNames;
-						processModule(referenceModule, importedNames);
+
+						processModule(
+							referenceModule,
+							importedNames === false
+								? NOTHING_USED
+								: importedNames === true
+								? NS_OBJ_USED
+								: importedNames.map(n => (Array.isArray(n) ? n : [n]))
+						);
 					};
 
 					for (const module of modules) {
-						moduleGraph.getExportsInfo(module).setHasUseInfo();
+						const exportsInfo = moduleGraph.getExportsInfo(module);
+						exportInfoToModuleMap.set(exportsInfo, module);
+						exportsInfo.setHasUseInfo();
 					}
 
 					/** @type {Queue<DependenciesBlock>} */
@@ -103,7 +145,7 @@ class FlagDependencyUsagePlugin {
 						for (const dep of deps) {
 							const module = moduleGraph.getModule(dep);
 							if (module) {
-								processModule(module, true);
+								processModule(module, NS_OBJ_USED);
 							}
 						}
 					}

lib/FunctionModuleTemplatePlugin.js

@@ -27,6 +27,32 @@ const joinIterableWithComma = iterable => {
 	return str;
 };
 
+const printExportsInfoToSource = (source, indent, exportsInfo) => {
+	let hasExports = false;
+	for (const exportInfo of exportsInfo.orderedExports) {
+		source.add(
+			Template.toComment(
+				`${indent}export ${
+					exportInfo.name
+				} [${exportInfo.getProvidedInfo()}] [${exportInfo.getUsedInfo()}] [${exportInfo.getRenameInfo()}]`
+			) + "\n"
+		);
+		if (exportInfo.exportsInfo) {
+			printExportsInfoToSource(source, indent + "  ", exportInfo.exportsInfo);
+		}
+		hasExports = true;
+	}
+	const otherExportsInfo = exportsInfo.otherExportsInfo;
+	if (otherExportsInfo.provided !== false || otherExportsInfo.used !== false) {
+		const title = hasExports ? "other exports" : "exports";
+		source.add(
+			Template.toComment(
+				`${indent}${title} [${otherExportsInfo.getProvidedInfo()}] [${otherExportsInfo.getUsedInfo()}]`
+			) + "\n"
+		);
+	}
+};
+
 class FunctionModuleTemplatePlugin {
 	constructor({ compilation }) {
 		this.compilation = compilation;
@@ -84,26 +110,7 @@ class FunctionModuleTemplatePlugin {
 					source.add("  !*** " + reqStr + " ***!\n");
 					source.add("  \\****" + reqStrStar + "****/\n");
 					const exportsInfo = moduleGraph.getExportsInfo(module);
-					for (const exportInfo of exportsInfo.orderedExports) {
+					printExportsInfoToSource(source, "", exportsInfo);
-						source.add(
-							Template.toComment(
-								`export ${
-									exportInfo.name
-								} [${exportInfo.getProvidedInfo()}] [${exportInfo.getUsedInfo()}] [${exportInfo.getRenameInfo()}]`
-							) + "\n"
-						);
-					}
-					const otherExportsInfo = exportsInfo.otherExportsInfo;
-					if (
-						otherExportsInfo.provided !== false ||
-						otherExportsInfo.used !== false
-					) {
-						source.add(
-							Template.toComment(
-								`other exports [${otherExportsInfo.getProvidedInfo()}] [${otherExportsInfo.getUsedInfo()}]`
-							) + "\n"
-						);
-					}
 					source.add(
 						Template.toComment(
 							`runtime requirements: ${joinIterableWithComma(

lib/JavascriptParser.js

@@ -91,10 +91,14 @@ class JavascriptParser {
 			typeof: new HookMap(() => new SyncBailHook(["expression"])),
 			importCall: new SyncBailHook(["expression"]),
 			call: new HookMap(() => new SyncBailHook(["expression"])),
-			callAnyMember: new HookMap(() => new SyncBailHook(["expression"])),
+			callMemberChain: new HookMap(
+				() => new SyncBailHook(["expression", "rootRaw", "members"])
+			),
 			new: new HookMap(() => new SyncBailHook(["expression"])),
 			expression: new HookMap(() => new SyncBailHook(["expression"])),
-			expressionAnyMember: new HookMap(() => new SyncBailHook(["expression"])),
+			expressionMemberChain: new HookMap(
+				() => new SyncBailHook(["expression", "rootRaw", "members"])
+			),
 			expressionConditionalOperator: new SyncBailHook(["expression"]),
 			expressionLogicalOperator: new SyncBailHook(["expression"]),
 			program: new SyncBailHook(["ast", "comments"])
@@ -1831,14 +1835,17 @@ class JavascriptParser {
 					let result = callHook.call(expression);
 					if (result === true) return;
 				}
-				// TODO replace with lastIndexOf for performance reasons
+			}
-				let identifier = callee.identifier.replace(/\.[^.]+$/, "");
+			const exprName = this.getNameForExpression(expression.callee);
-				if (identifier !== callee.identifier) {
+			if (exprName) {
-					const callAnyHook = this.hooks.callAnyMember.get(identifier);
+				const hook = this.hooks.callMemberChain.get(exprName.rootName);
-					if (callAnyHook !== undefined) {
+				if (hook !== undefined) {
-						let result = callAnyHook.call(expression);
+					const result = hook.call(
-						if (result === true) return;
+						expression,
-					}
+						exprName.rootRaw,
+						exprName.members
+					);
+					if (result === true) return;
 				}
 			}
 
@@ -1855,13 +1862,19 @@ class JavascriptParser {
 				const result = expressionHook.call(expression);
 				if (result === true) return;
 			}
-			const expressionAnyMemberHook = this.hooks.expressionAnyMember.get(
+			const expressionMemberChainHook = this.hooks.expressionMemberChain.get(
-				exprName.nameGeneral
+				exprName.rootName
 			);
-			if (expressionAnyMemberHook !== undefined) {
+			if (expressionMemberChainHook !== undefined) {
-				const result = expressionAnyMemberHook.call(expression);
+				const result = expressionMemberChainHook.call(
+					expression,
+					exprName.rootRaw,
+					exprName.members
+				);
 				if (result === true) return;
 			}
+			// TODO optimize case where expression.object is a MemberExpression too.
+			// we can keep info here when calling walkMemberExpression directly
 		}
 		this.walkExpression(expression.object);
 		if (expression.computed === true) this.walkExpression(expression.property);
@@ -2189,22 +2202,27 @@ class JavascriptParser {
 			expr.type === "MemberExpression" &&
 			expr.property.type === (expr.computed ? "Literal" : "Identifier")
 		) {
-			exprName.push(expr.computed ? expr.property.value : expr.property.name);
+			exprName.push(
+				expr.computed ? `${expr.property.value}` : expr.property.name
+			);
 			expr = expr.object;
 		}
 		let free;
+		let rootRaw;
 		if (expr.type === "Identifier") {
 			free = !this.scope.definitions.has(expr.name);
 			exprName.push(this.scope.renames.get(expr.name) || expr.name);
-		} else if (
+			rootRaw = expr.name;
-			expr.type === "ThisExpression" &&
-			this.scope.renames.get("this")
-		) {
-			free = true;
-			exprName.push(this.scope.renames.get("this"));
 		} else if (expr.type === "ThisExpression") {
-			free = this.scope.topLevelScope;
+			const rename = this.scope.renames.get("this");
-			exprName.push("this");
+			if (rename) {
+				free = true;
+				exprName.push(rename);
+			} else {
+				free = this.scope.topLevelScope;
+				exprName.push("this");
+			}
+			rootRaw = "this";
 		} else {
 			return null;
 		}
@@ -2217,9 +2235,13 @@ class JavascriptParser {
 		}
 		const name = prefix ? prefix + "." + exprName[0] : exprName[0];
 		const nameGeneral = prefix;
+		const rootName = exprName.pop();
 		return {
 			name,
 			nameGeneral,
+			rootName,
+			rootRaw,
+			members: exprName.reverse(),
 			free
 		};
 	}

lib/JsonGenerator.js

@@ -7,6 +7,7 @@
 
 const { ConcatSource, RawSource } = require("webpack-sources");
 const Generator = require("./Generator");
+const { UsageState } = require("./ModuleGraph");
 const RuntimeGlobals = require("./RuntimeGlobals");
 
 /** @typedef {import("webpack-sources").Source} Source */
@@ -64,7 +65,7 @@ class JsonGenerator extends Generator {
 		const providedExports = moduleGraph.getProvidedExports(module);
 		if (
 			Array.isArray(providedExports) &&
-			!module.isExportUsed(moduleGraph, "default")
+			module.isExportUsed(moduleGraph, "default") === UsageState.Unused
 		) {
 			// Only some exports are used: We can optimize here, by only generating a part of the JSON
 			const reducedJson = {};

lib/Module.js

@@ -18,6 +18,7 @@ const makeSerializable = require("./util/makeSerializable");
 /** @typedef {import("./Dependency")} Dependency */
 /** @typedef {import("./DependencyTemplates")} DependencyTemplates */
 /** @typedef {import("./FileSystemInfo")} FileSystemInfo */
+/** @typedef {import("./ModuleGraph").UsageStateType} UsageStateType */
 /** @typedef {import("./RequestShortener")} RequestShortener */
 /** @typedef {import("./RuntimeTemplate")} RuntimeTemplate */
 /** @typedef {import("./WebpackError")} WebpackError */
@@ -385,23 +386,22 @@ class Module extends DependenciesBlock {
 
 	/**
 	 * @param {ModuleGraph} moduleGraph the module graph
-	 * @param {string} exportName a name of an export
+	 * @param {string | string[]} exportName a name of an export
-	 * @returns {boolean} true, if the export is used
+	 * @returns {UsageStateType} state of the export
 	 */
 	isExportUsed(moduleGraph, exportName) {
-		const exportInfo = moduleGraph.getReadOnlyExportInfo(this, exportName);
+		return moduleGraph.getExportsInfo(this).isExportUsed(exportName);
-		return exportInfo.used !== false;
 	}
 
 	// TODO move to ModuleGraph
 	/**
 	 * @param {ModuleGraph} moduleGraph the module graph
-	 * @param {string} exportName a name of an export
+	 * @param {string | string[]} exportName a name of an export
-	 * @returns {string | false} false, when module or referenced export is unused.
+	 * @returns {string | string[] | false} false, when module or referenced export is unused.
 	 *                           string, the mangled export name when used.
 	 */
 	getUsedName(moduleGraph, exportName) {
-		return moduleGraph.getExportInfo(this, exportName).getUsedName();
+		return moduleGraph.getExportsInfo(this).getUsedName(exportName);
 	}
 
 	/**

lib/ModuleGraph.js

@@ -21,6 +21,16 @@ const SortableSet = require("./util/SortableSet");
  * @returns {string}
  */
 
+/** @typedef {0|1|2|3|4} UsageStateType */
+
+const UsageState = Object.freeze({
+	NoInfo: /** @type {0} */ (0),
+	Unused: /** @type {1} */ (1),
+	Unknown: /** @type {2} */ (2),
+	OnlyPropertiesUsed: /** @type {3} */ (3),
+	Used: /** @type {4} */ (4)
+});
+
 class ExportsInfo {
 	constructor() {
 		/** @type {Map<string, ExportInfo>} */
@@ -92,21 +102,21 @@ class ExportsInfo {
 
 	setHasUseInfo() {
 		for (const exportInfo of this._exports.values()) {
-			if (exportInfo.used === undefined) {
+			if (exportInfo.used === UsageState.NoInfo) {
-				exportInfo.used = false;
+				exportInfo.used = UsageState.Unused;
 			}
 			if (exportInfo.canMangleUse === undefined) {
 				exportInfo.canMangleUse = true;
 			}
 		}
-		if (this._otherExportsInfo.used === undefined) {
+		if (this._otherExportsInfo.used === UsageState.NoInfo) {
-			this._otherExportsInfo.used = false;
+			this._otherExportsInfo.used = UsageState.Unused;
 		}
 		if (this._otherExportsInfo.canMangleUse === undefined) {
 			this._otherExportsInfo.canMangleUse = true;
 		}
-		if (this._sideEffectsOnlyInfo.used === undefined) {
+		if (this._sideEffectsOnlyInfo.used === UsageState.NoInfo) {
-			this._sideEffectsOnlyInfo.used = false;
+			this._sideEffectsOnlyInfo.used = UsageState.Unused;
 		}
 	}
 
@@ -127,6 +137,20 @@ class ExportsInfo {
 		return this._otherExportsInfo;
 	}
 
+	/**
+	 * @param {string[]=} name the export name
+	 * @returns {ExportsInfo | undefined} the nested exports info
+	 */
+	getNestedExportsInfo(name) {
+		if (Array.isArray(name) && name.length > 0) {
+			let info = this._exports.get(name[0]);
+			if (info === undefined) info = this._otherExportsInfo;
+			if (!info.exportsInfo) return undefined;
+			return info.exportsInfo.getNestedExportsInfo(name.slice(1));
+		}
+		return this;
+	}
+
 	/**
 	 * @returns {boolean} true, if this call changed something
 	 */
@@ -163,8 +187,8 @@ class ExportsInfo {
 			changed = true;
 		}
 		for (const exportInfo of this._exports.values()) {
-			if (exportInfo.used !== true && exportInfo.used !== null) {
+			if (exportInfo.used < UsageState.Unknown) {
-				exportInfo.used = null;
+				exportInfo.used = UsageState.Unknown;
 				changed = true;
 			}
 			if (exportInfo.canMangleUse !== false) {
@@ -172,11 +196,8 @@ class ExportsInfo {
 				changed = true;
 			}
 		}
-		if (
+		if (this._otherExportsInfo.used < UsageState.Unknown) {
-			this._otherExportsInfo.used !== true &&
+			this._otherExportsInfo.used = UsageState.Unknown;
-			this._otherExportsInfo.used !== null
-		) {
-			this._otherExportsInfo.used = null;
 			changed = true;
 		}
 		if (this._otherExportsInfo.canMangleUse !== false) {
@@ -192,10 +213,10 @@ class ExportsInfo {
 			this._isUsed = true;
 			changed = true;
 		}
-		this.getExportInfo("default").used = true;
+		this.getExportInfo("default").used = UsageState.Used;
 		for (const exportInfo of this._exports.values()) {
-			if (exportInfo.used !== true && exportInfo.used !== null) {
+			if (exportInfo.used < UsageState.Unknown) {
-				exportInfo.used = null;
+				exportInfo.used = UsageState.Unknown;
 				changed = true;
 			}
 			if (exportInfo.name !== "default" && exportInfo.canMangleUse !== false) {
@@ -203,11 +224,8 @@ class ExportsInfo {
 				changed = true;
 			}
 		}
-		if (
+		if (this._otherExportsInfo.used < UsageState.Unknown) {
-			this._otherExportsInfo.used !== true &&
+			this._otherExportsInfo.used = UsageState.Unknown;
-			this._otherExportsInfo.used !== null
-		) {
-			this._otherExportsInfo.used = null;
 			changed = true;
 		}
 		if (this._otherExportsInfo.canMangleUse !== false) {
@@ -218,22 +236,22 @@ class ExportsInfo {
 	}
 
 	setUsedForSideEffectsOnly() {
-		if (this._sideEffectsOnlyInfo.used === false) {
+		if (this._sideEffectsOnlyInfo.used === UsageState.Unused) {
-			this._sideEffectsOnlyInfo.used = true;
+			this._sideEffectsOnlyInfo.used = UsageState.Used;
 			return true;
 		}
 		return false;
 	}
 
 	isUsed() {
-		if (this._otherExportsInfo.used !== false) {
+		if (this._otherExportsInfo.used !== UsageState.Unused) {
 			return true;
 		}
-		if (this._sideEffectsOnlyInfo.used !== false) {
+		if (this._sideEffectsOnlyInfo.used !== UsageState.Unused) {
 			return true;
 		}
 		for (const exportInfo of this._exports.values()) {
-			if (exportInfo.used !== false) {
+			if (exportInfo.used !== UsageState.Unused) {
 				return true;
 			}
 		}
@@ -242,30 +260,32 @@ class ExportsInfo {
 
 	getUsedExports() {
 		switch (this._otherExportsInfo.used) {
-			case undefined:
+			case UsageState.NoInfo:
 				return null;
-			case null:
+			case UsageState.Unknown:
 				return true;
-			case true:
+			case UsageState.OnlyPropertiesUsed:
+			case UsageState.Used:
 				return true;
 		}
 		const array = [];
 		if (!this._exportsAreOrdered) this._sortExports();
 		for (const exportInfo of this._exports.values()) {
 			switch (exportInfo.used) {
-				case undefined:
+				case UsageState.NoInfo:
 					return null;
-				case null:
+				case UsageState.Unknown:
 					return true;
-				case true:
+				case UsageState.OnlyPropertiesUsed:
+				case UsageState.Used:
 					array.push(exportInfo.name);
 			}
 		}
 		if (array.length === 0) {
 			switch (this._sideEffectsOnlyInfo.used) {
-				case undefined:
+				case UsageState.NoInfo:
 					return null;
-				case false:
+				case UsageState.Unused:
 					return false;
 			}
 		}
@@ -296,12 +316,61 @@ class ExportsInfo {
 		return array;
 	}
 
+	/**
+	 * @param {string | string[]} name the name of the export
+	 * @returns {boolean | undefined | null} if the export is provided
+	 */
 	isExportProvided(name) {
+		if (Array.isArray(name)) {
+			// TODO follow nested exports
+			return this.isExportProvided(name[0]);
+		}
 		let info = this._exports.get(name);
 		if (info === undefined) info = this._otherExportsInfo;
 		return info.provided;
 	}
 
+	/**
+	 * @param {string | string[]} name export name
+	 * @returns {UsageStateType} usage status
+	 */
+	isExportUsed(name) {
+		if (Array.isArray(name)) {
+			if (name.length === 0) return this.otherExportsInfo.used;
+			// TODO follow nested exports
+			return this.isExportUsed(name[0]);
+		}
+		let info = this._exports.get(name);
+		if (info === undefined) info = this._otherExportsInfo;
+		return info.used;
+	}
+
+	/**
+	 * @param {string | string[]} name the export name
+	 * @returns {string | string[] | false} the used name
+	 */
+	getUsedName(name) {
+		if (Array.isArray(name)) {
+			// TODO improve this
+			if (name.length === 0) return name;
+			let info = this._exports.get(name[0]);
+			if (info === undefined) info = this._otherExportsInfo;
+			const x = info.getUsedName();
+			if (!x) return false;
+			if (info.exportsInfo) {
+				const nested = info.exportsInfo.getUsedName(name.slice(1));
+				if (!nested) return false;
+				return [x].concat(nested);
+			} else {
+				return [x].concat(name.slice(1));
+			}
+		} else {
+			let info = this._exports.get(name);
+			if (info === undefined) info = this._otherExportsInfo;
+			return info.getUsedName();
+		}
+	}
+
 	getRestoreProvidedData() {
 		const otherProvided = this._otherExportsInfo.provided;
 		const otherCanMangleProvide = this._otherExportsInfo.canMangleProvide;
@@ -350,14 +419,8 @@ class ExportInfo {
 		this.name = name;
 		/** @type {string | null} */
 		this.usedName = initFrom ? initFrom.usedName : null;
-		/**
+		/** @type {UsageStateType} */
-		 * true: it is used
+		this.used = initFrom ? initFrom.used : UsageState.NoInfo;
-		 * false: it is not used
-		 * null: only the runtime knows if it is used
-		 * undefined: it was not determined if it is used
-		 * @type {boolean | null | undefined}
-		 */
-		this.used = initFrom ? initFrom.used : undefined;
 		/**
 		 * true: it is provided
 		 * false: it is not provided
@@ -380,6 +443,8 @@ class ExportInfo {
 		 * @type {boolean | undefined}
 		 */
 		this.canMangleUse = initFrom ? initFrom.canMangleUse : undefined;
+		/** @type {ExportsInfo=} */
+		this.exportsInfo = undefined;
 	}
 
 	get canMangle() {
@@ -406,20 +471,22 @@ class ExportInfo {
 	}
 
 	getUsedName() {
-		if (this.used === false) return false;
+		if (this.used === UsageState.Unused) return false;
 		return this.usedName || this.name;
 	}
 
 	getUsedInfo() {
 		switch (this.used) {
-			case undefined:
+			case UsageState.NoInfo:
 				return "no usage info";
-			case null:
+			case UsageState.Unknown:
 				return "maybe used (runtime-defined)";
-			case true:
+			case UsageState.Used:
 				return "used";
-			case false:
+			case UsageState.Unused:
 				return "unused";
+			case UsageState.OnlyPropertiesUsed:
+				return "only properties used";
 		}
 	}
 
@@ -828,7 +895,7 @@ class ModuleGraph {
 
 	/**
 	 * @param {Module} module the module
-	 * @param {string} exportName a name of an export
+	 * @param {string | string[]} exportName a name of an export
 	 * @returns {boolean | null} true, if the export is provided by the module.
 	 *                           null, if it's unknown.
 	 *                           false, if it's not provided.
@@ -1044,3 +1111,6 @@ const deprecateMap = new Map();
 
 module.exports = ModuleGraph;
 module.exports.ModuleGraphConnection = ModuleGraphConnection;
+module.exports.ExportsInfo = ExportsInfo;
+module.exports.ExportInfo = ExportInfo;
+module.exports.UsageState = UsageState;

lib/RuntimeTemplate.js

@@ -7,6 +7,7 @@
 
 const RuntimeGlobals = require("./RuntimeGlobals");
 const Template = require("./Template");
+const propertyAccess = require("./util/propertyAccess");
 
 /** @typedef {import("./AsyncDependenciesBlock")} AsyncDependenciesBlock */
 /** @typedef {import("./ChunkGraph")} ChunkGraph */
@@ -14,6 +15,14 @@ const Template = require("./Template");
 /** @typedef {import("./ModuleGraph")} ModuleGraph */
 /** @typedef {import("./RequestShortener")} RequestShortener */
 
+const arrayEquals = (a, b) => {
+	if (a.length !== b.length) return false;
+	for (let i = 0; i < a.length; i++) {
+		if (a[i] !== b[i]) return false;
+	}
+	return true;
+};
+
 class RuntimeTemplate {
 	/**
 	 * @param {TODO} outputOptions the compilation output options
@@ -506,7 +515,7 @@ class RuntimeTemplate {
 	 * @param {ModuleGraph} options.moduleGraph the module graph
 	 * @param {Module} options.module the module
 	 * @param {string} options.request the request
-	 * @param {string} options.exportName the export name
+	 * @param {string | string[]} options.exportName the export name
 	 * @param {Module} options.originModule the origin module
 	 * @param {boolean} options.asiSafe true, if location is safe for ASI, a bracket can be emitted
 	 * @param {boolean} options.isCall true, if expression will be called
@@ -532,24 +541,30 @@ class RuntimeTemplate {
 				request
 			});
 		}
+		if (!Array.isArray(exportName)) {
+			exportName = exportName ? [exportName] : [];
+		}
 		const exportsType = module.buildMeta && module.buildMeta.exportsType;
 
 		if (!exportsType) {
-			if (exportName === "default") {
+			if (exportName.length > 0 && exportName[0] === "default") {
 				if (!originModule.buildMeta.strictHarmonyModule) {
 					if (isCall) {
-						return `${importVar}_default()`;
+						return `${importVar}_default()${propertyAccess(exportName, 1)}`;
 					} else if (asiSafe) {
-						return `(${importVar}_default())`;
+						return `(${importVar}_default()${propertyAccess(exportName, 1)})`;
 					} else {
-						return `${importVar}_default.a`;
+						return `${importVar}_default.a${propertyAccess(exportName, 1)}`;
 					}
 				} else {
-					return importVar;
+					return `${importVar}${propertyAccess(exportName, 1)}`;
 				}
 			} else if (originModule.buildMeta.strictHarmonyModule) {
-				if (exportName) {
+				if (exportName.length > 0) {
-					return "/* non-default import from non-esm module */undefined";
+					return (
+						"/* non-default import from non-esm module */undefined" +
+						propertyAccess(exportName, 1)
+					);
 				} else {
 					runtimeRequirements.add(RuntimeGlobals.createFakeNamespaceObject);
 					return `/*#__PURE__*/${
@@ -560,26 +575,30 @@ class RuntimeTemplate {
 		}
 
 		if (exportsType === "named") {
-			if (exportName === "default") {
+			if (exportName.length > 0 && exportName[0] === "default") {
-				return importVar;
+				return `${importVar}${propertyAccess(exportName, 1)}`;
-			} else if (!exportName) {
+			} else if (exportName.length === 0) {
 				return `${importVar}_namespace`;
 			}
 		}
 
-		if (exportName) {
+		if (exportName.length > 0) {
-			const used = module.getUsedName(moduleGraph, exportName);
+			const exportsInfo = moduleGraph.getExportsInfo(module);
+			const used = exportsInfo.getUsedName(exportName);
 			if (!used) {
-				const comment = Template.toNormalComment(`unused export ${exportName}`);
+				const comment = Template.toNormalComment(
+					`unused export ${exportName.join(".")}`
+				);
 				return `${comment} undefined`;
 			}
-			const comment =
+			const comment = arrayEquals(used, exportName)
-				used !== exportName ? Template.toNormalComment(exportName) + " " : "";
+				? ""
-			const access = `${importVar}[${comment}${JSON.stringify(used)}]`;
+				: Template.toNormalComment(exportName.join(".")) + " ";
-			if (isCall) {
+			const access = `${importVar}${comment}${propertyAccess(used)}`;
-				if (callContext === false && asiSafe) {
+			if (isCall && callContext === false) {
+				if (asiSafe) {
 					return `(0,${access})`;
-				} else if (callContext === false) {
+				} else {
 					return `Object(${access})`;
 				}
 			}

lib/dependencies/DependencyReference.js

@@ -14,7 +14,7 @@ class DependencyReference {
 	/**
 	 *
 	 * @param {ModuleCallback} moduleCallback a callback to get the referenced module
-	 * @param {string[] | boolean} importedNames imported named from the module
+	 * @param {(string | string[])[] | boolean} importedNames imported named from the module
 	 * @param {boolean=} weak if this is a weak reference
 	 * @param {number} order the order information or NaN if don't care
 	 */

lib/dependencies/HarmonyExportDependencyParserPlugin.js

@@ -95,7 +95,7 @@ module.exports = class HarmonyExportDependencyParserPlugin {
 					dep = new HarmonyExportImportedSpecifierDependency(
 						settings.source,
 						settings.sourceOrder,
-						settings.id,
+						settings.ids,
 						name,
 						harmonyNamedExports,
 						null,
@@ -125,7 +125,7 @@ module.exports = class HarmonyExportDependencyParserPlugin {
 				const dep = new HarmonyExportImportedSpecifierDependency(
 					source,
 					parser.state.lastHarmonyImportOrder,
-					id,
+					id ? [id] : [],
 					name,
 					harmonyNamedExports,
 					harmonyStarExports && harmonyStarExports.slice(),

lib/dependencies/HarmonyExportImportedSpecifierDependency.js

@@ -7,6 +7,7 @@
 
 const HarmonyLinkingError = require("../HarmonyLinkingError");
 const InitFragment = require("../InitFragment");
+const { UsageState } = require("../ModuleGraph");
 const RuntimeGlobals = require("../RuntimeGlobals");
 const Template = require("../Template");
 const { intersect } = require("../util/SetHelpers");
@@ -21,14 +22,15 @@ const HarmonyImportDependency = require("./HarmonyImportDependency");
 /** @typedef {import("../DependencyTemplate").DependencyTemplateContext} DependencyTemplateContext */
 /** @typedef {import("../Module")} Module */
 /** @typedef {import("../ModuleGraph")} ModuleGraph */
+/** @typedef {import("../ModuleGraph").ExportsInfo} ExportsInfo */
 /** @typedef {import("../WebpackError")} WebpackError */
 /** @typedef {import("../util/createHash").Hash} Hash */
 
-/** @typedef {"missing"|"unused"|"empty-star"|"reexport-non-harmony-default"|"reexport-named-default"|"reexport-namespace-object"|"reexport-non-harmony-default-strict"|"reexport-fake-namespace-object"|"rexport-non-harmony-undefined"|"normal-reexport"|"dynamic-reexport"} ExportModeType */
+/** @typedef {"missing"|"unused"|"empty-star"|"reexport-non-harmony-default"|"reexport-named-default"|"reexport-namespace-object"|"reexport-partial-namespace-object"|"reexport-non-harmony-default-strict"|"reexport-fake-namespace-object"|"reexport-non-harmony-undefined"|"normal-reexport"|"dynamic-reexport"} ExportModeType */
 
-const idSymbol = Symbol("HarmonyExportImportedSpecifierDependency.id");
+const idsSymbol = Symbol("HarmonyExportImportedSpecifierDependency.ids");
 
-/** @type {Map<string, string>} */
+/** @type {Map<string, string[]>} */
 const EMPTY_MAP = new Map();
 
 /** @type {Set<string>} */
@@ -43,8 +45,10 @@ class ExportMode {
 		this.type = type;
 		/** @type {string|null} */
 		this.name = null;
-		/** @type {Map<string, string>} */
+		/** @type {Map<string, string[]>} */
 		this.map = EMPTY_MAP;
+		/** @type {ExportsInfo} */
+		this.partialNamespaceExportsInfo = undefined;
 		/** @type {Set<string>|null} */
 		this.ignored = null;
 		/** @type {Set<string>|null} */
@@ -60,7 +64,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 	/**
 	 * @param {string} request the request string
 	 * @param {number} sourceOrder the order in the original source file
-	 * @param {string | null} id the requested export name of the imported module
+	 * @param {string[]} ids the requested export name of the imported module
 	 * @param {string | null} name the export name of for this module
 	 * @param {Set<string>} activeExports other named exports in the module
 	 * @param {Iterable<Dependency>} otherStarExports other star exports in the module
@@ -69,7 +73,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 	constructor(
 		request,
 		sourceOrder,
-		id,
+		ids,
 		name,
 		activeExports,
 		otherStarExports,
@@ -77,32 +81,47 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 	) {
 		super(request, sourceOrder);
 
-		this.id = id;
+		this.ids = ids;
 		this.name = name;
 		this.activeExports = activeExports;
 		this.otherStarExports = otherStarExports;
 		this.strictExportPresence = strictExportPresence;
 	}
 
+	// TODO webpack 6 remove
+	get id() {
+		throw new Error("id was renamed to ids and type changed to string[]");
+	}
+
+	// TODO webpack 6 remove
+	getId() {
+		throw new Error("id was renamed to ids and type changed to string[]");
+	}
+
+	// TODO webpack 6 remove
+	setId() {
+		throw new Error("id was renamed to ids and type changed to string[]");
+	}
+
 	get type() {
 		return "harmony export imported specifier";
 	}
 
 	/**
 	 * @param {ModuleGraph} moduleGraph the module graph
-	 * @returns {string} the imported id
+	 * @returns {string[]} the imported id
 	 */
-	getId(moduleGraph) {
+	getIds(moduleGraph) {
-		return moduleGraph.getMeta(this)[idSymbol] || this.id;
+		return moduleGraph.getMeta(this)[idsSymbol] || this.ids;
 	}
 
 	/**
 	 * @param {ModuleGraph} moduleGraph the module graph
-	 * @param {string} id the imported id
+	 * @param {string[]} ids the imported ids
 	 * @returns {void}
 	 */
-	setId(moduleGraph, id) {
+	setIds(moduleGraph, ids) {
-		moduleGraph.getMeta(this)[idSymbol] = id;
+		moduleGraph.getMeta(this)[idsSymbol] = ids;
 	}
 
 	/**
@@ -112,9 +131,10 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 	 */
 	getMode(moduleGraph, ignoreUnused) {
 		const name = this.name;
-		const id = this.getId(moduleGraph);
+		const ids = this.getIds(moduleGraph);
 		const parentModule = moduleGraph.getParentModule(this);
 		const importedModule = moduleGraph.getModule(this);
+		const exportsInfo = moduleGraph.getExportsInfo(parentModule);
 
 		if (!importedModule) {
 			const mode = new ExportMode("missing");
@@ -127,8 +147,8 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 		if (
 			!ignoreUnused &&
 			(name
-				? parentModule.isExportUsed(moduleGraph, name) === false
+				? exportsInfo.isExportUsed(name) === UsageState.Unused
-				: parentModule.isModuleUsed(moduleGraph) === false)
+				: exportsInfo.isUsed() === false)
 		) {
 			const mode = new ExportMode("unused");
 
@@ -141,7 +161,12 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 
 		// Special handling for reexporting the default export
 		// from non-harmony modules
-		if (name && id === "default" && importedModule.buildMeta) {
+		if (
+			name &&
+			ids.length > 0 &&
+			ids[0] === "default" &&
+			importedModule.buildMeta
+		) {
 			if (!importedModule.buildMeta.exportsType) {
 				const mode = new ExportMode(
 					strictHarmonyModule
@@ -169,15 +194,16 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 		// reexporting with a fixed name
 		if (name) {
 			let mode;
+			const exportInfo = exportsInfo.getReadOnlyExportInfo(name);
 
-			if (id) {
+			if (ids.length > 0) {
 				// export { name as name }
 				if (isNotAHarmonyModule && strictHarmonyModule) {
-					mode = new ExportMode("rexport-non-harmony-undefined");
+					mode = new ExportMode("reexport-non-harmony-undefined");
 					mode.name = name;
 				} else {
 					mode = new ExportMode("normal-reexport");
-					mode.map = new Map([[name, id]]);
+					mode.map = new Map([[name, ids]]);
 					mode.checked = EMPTY_SET;
 				}
 			} else {
@@ -185,6 +211,14 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 				if (isNotAHarmonyModule && strictHarmonyModule) {
 					mode = new ExportMode("reexport-fake-namespace-object");
 					mode.name = name;
+				} else if (
+					exportInfo.used === UsageState.OnlyPropertiesUsed &&
+					exportInfo.exportsInfo &&
+					exportInfo.exportsInfo.otherExportsInfo.used === UsageState.Unused
+				) {
+					mode = new ExportMode("reexport-partial-namespace-object");
+					mode.name = name;
+					mode.partialNamespaceExportsInfo = exportInfo.exportsInfo;
 				} else {
 					mode = new ExportMode("reexport-namespace-object");
 					mode.name = name;
@@ -198,12 +232,12 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 
 		// Star reexporting
 
-		const exportsInfo = moduleGraph.getExportsInfo(parentModule);
 		const importedExportsInfo = moduleGraph.getExportsInfo(importedModule);
 
 		const noExtraExports =
 			importedExportsInfo.otherExportsInfo.provided === false;
-		const noExtraImports = exportsInfo.otherExportsInfo.used === false;
+		const noExtraImports =
+			exportsInfo.otherExportsInfo.used === UsageState.Unused;
 
 		const ignoredExports = new Set([
 			"default",
@@ -233,7 +267,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 		if (noExtraImports) {
 			for (const exportInfo of exportsInfo.exports) {
 				if (ignoredExports.has(exportInfo.name)) continue;
-				if (exportInfo.used !== false) {
+				if (exportInfo.used !== UsageState.Unused) {
 					imports.add(exportInfo.name);
 				}
 			}
@@ -272,10 +306,10 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 			return mode;
 		}
 
-		/** @type {Map<string, string>} */
+		/** @type {Map<string, string[]>} */
 		const map = new Map();
 		for (const exportName of merged) {
-			map.set(exportName, exportName);
+			map.set(exportName, [exportName]);
 		}
 
 		const mode = new ExportMode("normal-reexport");
@@ -310,10 +344,37 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 					this.sourceOrder
 				);
 
+			case "reexport-partial-namespace-object": {
+				const importedNames = [];
+				const processExportsInfo = (prefix, exportsInfo) => {
+					for (const exportInfo of exportsInfo.orderedExports) {
+						if (
+							exportInfo.used === UsageState.OnlyPropertiesUsed &&
+							exportInfo.exportsInfo &&
+							exportInfo.exportsInfo.otherExportsInfo.used === UsageState.Unused
+						) {
+							processExportsInfo(
+								prefix.concat(exportInfo.name),
+								exportInfo.exportsInfo
+							);
+						} else if (exportInfo.used !== UsageState.Unused) {
+							importedNames.push(prefix.concat(exportInfo.name));
+						}
+					}
+				};
+				processExportsInfo([], mode.partialNamespaceExportsInfo);
+				return new DependencyReference(
+					mode.getModule,
+					importedNames,
+					false,
+					this.sourceOrder
+				);
+			}
+
 			case "reexport-namespace-object":
 			case "reexport-non-harmony-default-strict":
 			case "reexport-fake-namespace-object":
-			case "rexport-non-harmony-undefined":
+			case "reexport-non-harmony-undefined":
 				return new DependencyReference(
 					mode.getModule,
 					true,
@@ -395,20 +456,34 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 				};
 			case "normal-reexport":
 				return {
-					exports: Array.from(mode.map.keys()),
+					exports: Array.from(mode.map.keys()).map(name => ({
+						name,
+						from: mode.getModule(),
+						export: mode.map.get(name)
+					})),
 					dependencies: [mode.getModule()]
 				};
 			case "reexport-fake-namespace-object":
-			case "reexport-namespace-object":
 			case "reexport-non-harmony-default":
 			case "reexport-non-harmony-default-strict":
-			case "rexport-non-harmony-undefined":
+			case "reexport-non-harmony-undefined":
 			case "reexport-named-default":
 				return {
 					exports: [mode.name],
 					dependencies: [mode.getModule()]
 				};
-
+			case "reexport-namespace-object":
+			case "reexport-partial-namespace-object":
+				return {
+					exports: [
+						{
+							name: mode.name,
+							from: mode.getModule(),
+							export: null
+						}
+					],
+					dependencies: [mode.getModule()]
+				};
 			default:
 				throw new Error(`Unknown mode ${mode.type}`);
 		}
@@ -457,18 +532,19 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 			return;
 		}
 
-		const id = this.getId(moduleGraph);
+		const ids = this.getIds(moduleGraph);
 
 		if (!importedModule.buildMeta || !importedModule.buildMeta.exportsType) {
 			// It's not an harmony module
 			if (
 				moduleGraph.getParentModule(this).buildMeta.strictHarmonyModule &&
-				id !== "default"
+				(ids.length === 0 || ids[0] !== "default")
 			) {
 				// In strict harmony modules we only support the default export
-				const exportName = id
+				const exportName =
-					? `the named export '${id}'`
+					ids.length > 0
-					: "the namespace object";
+						? `the named export ${ids.map(id => `'${id}'`).join(".")}`
+						: "the namespace object";
 
 				return [
 					new HarmonyLinkingError(
@@ -480,21 +556,21 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 			return;
 		}
 
-		if (!id) {
+		if (ids.length === 0) {
 			return;
 		}
 
-		if (moduleGraph.isExportProvided(importedModule, id) !== false) {
+		if (moduleGraph.isExportProvided(importedModule, ids) !== false) {
 			// It's provided or we are not sure
 			return;
 		}
 
 		// We are sure that it's not provided
 		const idIsNotNameMessage =
-			id !== this.name ? ` (reexported as '${this.name}')` : "";
+			ids.join(".") !== this.name ? ` (reexported as '${this.name}')` : "";
-		const errorMessage = `"export '${id}'${idIsNotNameMessage} was not found in '${
+		const errorMessage = `"export ${this.ids
-			this.userRequest
+			.map(id => `'${id}'`)
-		}'`;
+			.join(".")}${idIsNotNameMessage} was not found in '${this.userRequest}'`;
 
 		return [new HarmonyLinkingError(errorMessage)];
 	}
@@ -513,7 +589,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 		hash.update(mode.type);
 		for (const [k, v] of mode.map) {
 			hash.update(k);
-			hash.update(v);
+			hash.update(v.join());
 		}
 		if (mode.ignored) {
 			hash.update("ignored");
@@ -527,7 +603,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 	serialize(context) {
 		const { write } = context;
 
-		write(this.id);
+		write(this.ids);
 		write(this.name);
 		write(this.activeExports);
 		write(this.otherStarExports);
@@ -539,7 +615,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 	deserialize(context) {
 		const { read } = context;
 
-		this.id = read();
+		this.ids = read();
 		this.name = read();
 		this.activeExports = read();
 		this.otherStarExports = read();
@@ -685,7 +761,7 @@ HarmonyExportImportedSpecifierDependency.Template = class HarmonyExportImportedS
 				);
 				break;
 
-			case "rexport-non-harmony-undefined":
+			case "reexport-non-harmony-undefined":
 				initFragments.push(
 					new InitFragment(
 						"/* harmony reexport (non default export from non-harmony) */ " +
@@ -720,6 +796,7 @@ HarmonyExportImportedSpecifierDependency.Template = class HarmonyExportImportedS
 				break;
 
 			case "reexport-namespace-object":
+			case "reexport-partial-namespace-object":
 				initFragments.push(
 					new InitFragment(
 						"/* harmony reexport (module object) */ " +

lib/dependencies/HarmonyImportDependencyParserPlugin.js

@@ -44,9 +44,10 @@ module.exports = class HarmonyImportDependencyParserPlugin {
 				if (!parser.state.harmonySpecifier) {
 					parser.state.harmonySpecifier = new Map();
 				}
+				const ids = id === null ? [] : [id];
 				parser.state.harmonySpecifier.set(name, {
 					source,
-					id,
+					ids,
 					sourceOrder: parser.state.lastHarmonyImportOrder
 				});
 				return true;
@@ -60,7 +61,7 @@ module.exports = class HarmonyImportDependencyParserPlugin {
 				const dep = new HarmonyImportSpecifierDependency(
 					settings.source,
 					settings.sourceOrder,
-					settings.id,
+					settings.ids,
 					name,
 					expr.range,
 					this.strictExportPresence
@@ -71,45 +72,40 @@ module.exports = class HarmonyImportDependencyParserPlugin {
 				parser.state.module.addDependency(dep);
 				return true;
 			});
-		parser.hooks.expressionAnyMember
+		parser.hooks.expressionMemberChain
 			.for("imported var")
-			.tap("HarmonyImportDependencyParserPlugin", expr => {
+			.tap("HarmonyImportDependencyParserPlugin", (expr, name, members) => {
-				const name = expr.object.name;
 				const settings = parser.state.harmonySpecifier.get(name);
-				if (settings.id !== null) return false;
+				const ids = settings.ids.concat(members);
 				const dep = new HarmonyImportSpecifierDependency(
 					settings.source,
 					settings.sourceOrder,
-					expr.property.name || expr.property.value,
+					ids,
 					name,
 					expr.range,
 					this.strictExportPresence
 				);
-				dep.shorthand = parser.scope.inShorthand;
-				dep.directImport = false;
 				dep.loc = expr.loc;
 				parser.state.module.addDependency(dep);
 				return true;
 			});
 		if (this.strictThisContextOnImports) {
 			// only in case when we strictly follow the spec we need a special case here
-			parser.hooks.callAnyMember
+			parser.hooks.callMemberChain
 				.for("imported var")
-				.tap("HarmonyImportDependencyParserPlugin", expr => {
+				.tap("HarmonyImportDependencyParserPlugin", (expr, name, members) => {
-					if (expr.callee.type !== "MemberExpression") return;
+					if (members.length <= 0) return;
-					if (expr.callee.object.type !== "Identifier") return;
-					const name = expr.callee.object.name;
 					const settings = parser.state.harmonySpecifier.get(name);
-					if (settings.id !== null) return false;
+					if (settings.ids.length > 0) return false;
+					const ids = settings.ids.concat(members);
 					const dep = new HarmonyImportSpecifierDependency(
 						settings.source,
 						settings.sourceOrder,
-						expr.callee.property.name || expr.callee.property.value,
+						ids,
 						name,
 						expr.callee.range,
 						this.strictExportPresence
 					);
-					dep.shorthand = parser.scope.inShorthand;
 					dep.directImport = false;
 					dep.namespaceObjectAsContext = true;
 					dep.loc = expr.callee.loc;
@@ -129,7 +125,7 @@ module.exports = class HarmonyImportDependencyParserPlugin {
 				const dep = new HarmonyImportSpecifierDependency(
 					settings.source,
 					settings.sourceOrder,
-					settings.id,
+					settings.ids,
 					name,
 					expr.range,
 					this.strictExportPresence

lib/dependencies/HarmonyImportSpecifierDependency.js

@@ -19,12 +19,12 @@ const HarmonyImportDependency = require("./HarmonyImportDependency");
 /** @typedef {import("../WebpackError")} WebpackError */
 /** @typedef {import("../util/createHash").Hash} Hash */
 
-const idSymbol = Symbol("HarmonyImportSpecifierDependency.id");
+const idsSymbol = Symbol("HarmonyImportSpecifierDependency.ids");
 
 class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
-	constructor(request, sourceOrder, id, name, range, strictExportPresence) {
+	constructor(request, sourceOrder, ids, name, range, strictExportPresence) {
 		super(request, sourceOrder);
-		this.id = id === null ? null : `${id}`;
+		this.ids = ids;
 		this.name = name;
 		this.range = range;
 		this.strictExportPresence = strictExportPresence;
@@ -34,25 +34,40 @@ class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
 		this.shorthand = undefined;
 	}
 
+	// TODO webpack 6 remove
+	get id() {
+		throw new Error("id was renamed to ids and type changed to string[]");
+	}
+
+	// TODO webpack 6 remove
+	getId() {
+		throw new Error("id was renamed to ids and type changed to string[]");
+	}
+
+	// TODO webpack 6 remove
+	setId() {
+		throw new Error("id was renamed to ids and type changed to string[]");
+	}
+
 	get type() {
 		return "harmony import specifier";
 	}
 
 	/**
 	 * @param {ModuleGraph} moduleGraph the module graph
-	 * @returns {string} the imported id
+	 * @returns {string[]} the imported ids
 	 */
-	getId(moduleGraph) {
+	getIds(moduleGraph) {
-		return moduleGraph.getMeta(this)[idSymbol] || this.id;
+		return moduleGraph.getMeta(this)[idsSymbol] || this.ids;
 	}
 
 	/**
 	 * @param {ModuleGraph} moduleGraph the module graph
-	 * @param {string} id the imported id
+	 * @param {string[]} ids the imported ids
 	 * @returns {void}
 	 */
-	setId(moduleGraph, id) {
+	setIds(moduleGraph, ids) {
-		moduleGraph.getMeta(this)[idSymbol] = id;
+		moduleGraph.getMeta(this)[idsSymbol] = ids;
 	}
 
 	/**
@@ -63,11 +78,10 @@ class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
 	getReference(moduleGraph) {
 		const module = moduleGraph.getModule(this);
 		if (!module) return null;
+		const ids = this.getIds(moduleGraph);
 		return new DependencyReference(
 			() => moduleGraph.getModule(this),
-			this.getId(moduleGraph) && !this.namespaceObjectAsContext
+			ids.length > 0 && !this.namespaceObjectAsContext ? [ids] : true,
-				? [this.getId(moduleGraph)]
-				: true,
 			false,
 			this.sourceOrder
 		);
@@ -113,16 +127,18 @@ class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
 			return;
 		}
 
+		const ids = this.getIds(moduleGraph);
 		if (!importedModule.buildMeta || !importedModule.buildMeta.exportsType) {
 			// It's not an harmony module
 			if (
 				moduleGraph.getParentModule(this).buildMeta.strictHarmonyModule &&
-				this.getId(moduleGraph) !== "default"
+				(ids.length === 0 || ids[0] !== "default")
 			) {
 				// In strict harmony modules we only support the default export
-				const exportName = this.getId(moduleGraph)
+				const exportName =
-					? `the named export '${this.getId(moduleGraph)}'`
+					ids.length > 0
-					: "the namespace object";
+						? `the named export '${ids[0]}'`
+						: "the namespace object";
 				return [
 					new HarmonyLinkingError(
 						`Can't import ${exportName} from non EcmaScript module (only default export is available)`
@@ -132,22 +148,21 @@ class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
 			return;
 		}
 
-		const id = this.getId(moduleGraph);
+		if (ids.length === 0) {
-		if (!id) {
 			return;
 		}
 
-		if (moduleGraph.isExportProvided(importedModule, id) !== false) {
+		if (moduleGraph.isExportProvided(importedModule, ids) !== false) {
 			// It's provided or we are not sure
 			return;
 		}
 
 		// We are sure that it's not provided
 		const idIsNotNameMessage =
-			id !== this.name ? ` (imported as '${this.name}')` : "";
+			ids[0] !== this.name ? ` (imported as '${this.name}')` : "";
-		const errorMessage = `"export '${this.getId(
+		const errorMessage = `"export ${ids
-			moduleGraph
+			.map(id => `'${id}'`)
-		)}'${idIsNotNameMessage} was not found in '${this.userRequest}'`;
+			.join(".")}${idIsNotNameMessage} was not found in '${this.userRequest}'`;
 		return [new HarmonyLinkingError(errorMessage)];
 	}
 
@@ -169,10 +184,11 @@ class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
 		super.updateHash(hash, chunkGraph);
 		const moduleGraph = chunkGraph.moduleGraph;
 		const importedModule = moduleGraph.getModule(this);
+		const ids = this.getIds(moduleGraph);
+		hash.update(ids.join());
 		if (importedModule) {
-			const id = this.getId(moduleGraph);
+			const exportsInfo = moduleGraph.getExportsInfo(importedModule);
-			hash.update(id + "");
+			hash.update(JSON.stringify(exportsInfo.getUsedName(ids)));
-			hash.update((id && importedModule.getUsedName(moduleGraph, id)) + "");
 			hash.update(
 				(!importedModule.buildMeta || importedModule.buildMeta.exportsType) + ""
 			);
@@ -181,7 +197,7 @@ class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
 
 	serialize(context) {
 		const { write } = context;
-		write(this.id);
+		write(this.ids);
 		write(this.name);
 		write(this.range);
 		write(this.strictExportPresence);
@@ -194,7 +210,7 @@ class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
 
 	deserialize(context) {
 		const { read } = context;
-		this.id = read();
+		this.ids = read();
 		this.name = read();
 		this.range = read();
 		this.strictExportPresence = read();
@@ -229,11 +245,12 @@ HarmonyImportSpecifierDependency.Template = class HarmonyImportSpecifierDependen
 		dep,
 		{ runtimeTemplate, module, moduleGraph, runtimeRequirements }
 	) {
+		const ids = dep.getIds(moduleGraph);
 		const exportExpr = runtimeTemplate.exportFromImport({
 			moduleGraph,
 			module: moduleGraph.getModule(dep),
 			request: dep.request,
-			exportName: dep.getId(moduleGraph),
+			exportName: ids,
 			originModule: module,
 			asiSafe: dep.shorthand,
 			isCall: dep.call,

lib/optimize/ConcatenatedModule.js

@@ -11,6 +11,7 @@ const DependencyTemplate = require("../DependencyTemplate");
 const InitFragment = require("../InitFragment");
 const JavascriptParser = require("../JavascriptParser");
 const Module = require("../Module");
+const { UsageState } = require("../ModuleGraph");
 const RuntimeGlobals = require("../RuntimeGlobals");
 const Template = require("../Template");
 const DependencyReference = require("../dependencies/DependencyReference");
@@ -23,6 +24,7 @@ const HarmonyImportSideEffectDependency = require("../dependencies/HarmonyImport
 const HarmonyImportSpecifierDependency = require("../dependencies/HarmonyImportSpecifierDependency");
 const createHash = require("../util/createHash");
 const contextify = require("../util/identifier").contextify;
+const propertyAccess = require("../util/propertyAccess");
 
 /** @typedef {import("webpack-sources").Source} Source */
 /** @typedef {import("../ChunkGraph")} ChunkGraph */
@@ -38,23 +40,29 @@ const contextify = require("../util/identifier").contextify;
 /** @typedef {import("../WebpackError")} WebpackError */
 /** @typedef {import("../util/createHash").Hash} Hash */
 
+/**
+ * @typedef {Object} ReexportInfo
+ * @property {Module} module
+ * @property {string[]} exportName
+ * @property {Dependency} dependency
+ */
+
 /** @typedef {ConcatenatedModuleInfo | ExternalModuleInfo } ModuleInfo */
 
 /**
  * @typedef {Object} ConcatenatedModuleInfo
  * @property {"concatenated"} type
  * @property {Module} module
- * @property {TODO} index
+ * @property {number} index
- * @property {TODO} ast
+ * @property {Object} ast
- * @property {TODO} internalSource
+ * @property {Source} internalSource
- * @property {TODO} source
+ * @property {ReplaceSource} source
  * @property {TODO} globalScope
  * @property {TODO} moduleScope
  * @property {TODO} internalNames
- * @property {TODO} globalExports
+ * @property {Map<string | true, string>} exportMap
- * @property {TODO} exportMap
+ * @property {Map<string, ReexportInfo>} reexportMap
- * @property {TODO} reexportMap
+ * @property {boolean} hasNamespaceObject
- * @property {TODO} hasNamespaceObject
  * @property {TODO} namespaceObjectSource
  */
 
@@ -62,12 +70,12 @@ const contextify = require("../util/identifier").contextify;
  * @typedef {Object} ExternalModuleInfo
  * @property {"external"} type
  * @property {Module} module
- * @property {TODO} index
+ * @property {number} index
- * @property {TODO} name
+ * @property {string} name
- * @property {TODO} interopNamespaceObjectUsed
+ * @property {boolean} interopNamespaceObjectUsed
- * @property {TODO} interopNamespaceObjectName
+ * @property {string} interopNamespaceObjectName
- * @property {TODO} interopDefaultAccessUsed
+ * @property {boolean} interopDefaultAccessUsed
- * @property {TODO} interopDefaultAccessName
+ * @property {string} interopDefaultAccessName
  */
 
 const RESERVED_NAMES = [
@@ -105,12 +113,27 @@ const RESERVED_NAMES = [
 	.join(",")
 	.split(",");
 
+const arrayEquals = (a, b) => {
+	if (a.length !== b.length) return false;
+	for (let i = 0; i < a.length; i++) {
+		if (a[i] !== b[i]) return false;
+	}
+	return true;
+};
 /**
  * @typedef {Object} ConcatenationEntry
  * @property {"concatenated" | "external"} type
  * @property {Module} module
  */
 
+/**
+ * @param {ModuleGraph} moduleGraph the module graph
+ * @param {ConcatenatedModuleInfo} info module info
+ * @param {Map<Module, ModuleInfo>} moduleToInfoMap moduleToInfoMap
+ * @param {RequestShortener} requestShortener requestShortener
+ * @param {boolean} strictHarmonyModule strictHarmonyModule
+ * @returns {void}
+ */
 const ensureNsObjSource = (
 	moduleGraph,
 	info,
@@ -125,11 +148,12 @@ const ensureNsObjSource = (
 			`var ${name} = {};`,
 			`${RuntimeGlobals.makeNamespaceObject}(${name});`
 		];
-		for (const exportName of moduleGraph.getProvidedExports(info.module)) {
+		const exportsInfo = moduleGraph.getExportsInfo(info.module);
+		for (const exportInfo of exportsInfo.orderedExports) {
 			const finalName = getFinalName(
 				moduleGraph,
 				info,
-				exportName,
+				[exportInfo.name],
 				moduleToInfoMap,
 				requestShortener,
 				false,
@@ -137,7 +161,7 @@ const ensureNsObjSource = (
 			);
 			nsObj.push(
 				`${RuntimeGlobals.definePropertyGetter}(${name}, ${JSON.stringify(
-					exportName
+					exportInfo.getUsedName()
 				)}, function() { return ${finalName}; });`
 			);
 		}
@@ -145,6 +169,15 @@ const ensureNsObjSource = (
 	}
 };
 
+/**
+ * @param {ModuleGraph} moduleGraph the module graph
+ * @param {Module} importedModule module
+ * @param {ExternalModuleInfo} info module info
+ * @param {string[]} exportName exportName
+ * @param {boolean} asCall asCall
+ * @param {boolean} strictHarmonyModule strictHarmonyModule
+ * @returns {string} expression to get value of external module
+ */
 const getExternalImport = (
 	moduleGraph,
 	importedModule,
@@ -154,54 +187,75 @@ const getExternalImport = (
 	strictHarmonyModule
 ) => {
 	const used =
-		exportName === true || importedModule.getUsedName(moduleGraph, exportName);
+		exportName.length === 0 ||
+		importedModule.getUsedName(moduleGraph, exportName);
 	if (!used) return "/* unused reexport */undefined";
-	const comment =
+	const comment = arrayEquals(used, exportName)
-		used !== exportName ? ` ${Template.toNormalComment(exportName)}` : "";
+		? ""
-	switch (importedModule.buildMeta.exportsType) {
+		: Template.toNormalComment(`${exportName.join(".")}`);
-		case "named":
+	let exprStart;
-			if (exportName === "default") {
+	if (exportName.length === 0) {
-				return info.name;
+		switch (importedModule.buildMeta.exportsType) {
-			} else if (exportName === true) {
+			case "named":
 				info.interopNamespaceObjectUsed = true;
-				return info.interopNamespaceObjectName;
+				exprStart = info.interopNamespaceObjectName;
-			} else {
 				break;
-			}
+			case "namespace":
-		case "namespace":
+				exprStart = info.name;
-			if (exportName === true) {
-				return info.name;
-			} else {
 				break;
-			}
+			default:
-		default:
+				if (strictHarmonyModule) {
-			if (strictHarmonyModule) {
-				if (exportName === "default") {
-					return info.name;
-				} else if (exportName === true) {
 					info.interopNamespaceObjectUsed = true;
-					return info.interopNamespaceObjectName;
+					exprStart = info.interopNamespaceObjectName;
-				} else {
+					break;
-					return "/* non-default import from non-esm module */undefined";
-				}
-			} else {
-				if (exportName === "default") {
-					info.interopDefaultAccessUsed = true;
-					return asCall
-						? `${info.interopDefaultAccessName}()`
-						: `${info.interopDefaultAccessName}.a`;
-				} else if (exportName === true) {
-					return info.name;
 				} else {
+					exprStart = info.name;
 					break;
 				}
-			}
+		}
+	} else {
+		switch (importedModule.buildMeta.exportsType) {
+			case "named":
+				if (exportName[0] === "default") {
+					exprStart = info.name;
+				}
+				break;
+			default:
+				if (strictHarmonyModule) {
+					if (exportName[0] === "default") {
+						exprStart = info.name;
+					} else {
+						exprStart = "/* non-default import from non-esm module */undefined";
+					}
+				} else {
+					if (exportName[0] === "default") {
+						info.interopDefaultAccessUsed = true;
+						exprStart = asCall
+							? `${info.interopDefaultAccessName}()`
+							: `${info.interopDefaultAccessName}.a`;
+					}
+				}
+				break;
+		}
 	}
-	const reference = `${info.name}[${JSON.stringify(used)}${comment}]`;
+	if (exprStart) {
-	if (asCall) return `Object(${reference})`;
+		return `${exprStart}${propertyAccess(exportName, 1)}`;
-	return reference;
+	}
+	const reference = `${info.name}${comment}${propertyAccess(used)}`;
+	return asCall ? `Object(${reference})` : reference;
 };
 
+/**
+ * @param {ModuleGraph} moduleGraph the module graph
+ * @param {ModuleInfo} info module info
+ * @param {string[]} exportName exportName
+ * @param {Map<Module, ModuleInfo>} moduleToInfoMap moduleToInfoMap
+ * @param {RequestShortener} requestShortener the request shortener
+ * @param {boolean} asCall asCall
+ * @param {boolean} strictHarmonyModule strictHarmonyModule
+ * @param {Set<ReexportInfo>} alreadyVisited alreadyVisited
+ * @returns {string} the final name
+ */
 const getFinalName = (
 	moduleGraph,
 	info,
@@ -214,21 +268,25 @@ const getFinalName = (
 ) => {
 	switch (info.type) {
 		case "concatenated": {
-			const directExport = info.exportMap.get(exportName);
+			if (exportName.length === 0) {
+				ensureNsObjSource(
+					moduleGraph,
+					info,
+					moduleToInfoMap,
+					requestShortener,
+					strictHarmonyModule
+				);
+				return info.internalNames.get(info.exportMap.get(true));
+			}
+			const exportId = exportName[0];
+			const directExport = info.exportMap.get(exportId);
+			const exportsInfo = moduleGraph.getExportsInfo(info.module);
 			if (directExport) {
-				if (exportName === true) {
+				if (exportsInfo.isExportUsed(exportName) === UsageState.Unused) {
-					ensureNsObjSource(
+					return `/* unused export */ undefined${propertyAccess(
-						moduleGraph,
+						exportName,
-						info,
+						1
-						moduleToInfoMap,
+					)}`;
-						requestShortener,
-						strictHarmonyModule
-					);
-				} else if (!info.module.isExportUsed(moduleGraph, exportName)) {
-					return "/* unused export */ undefined";
-				}
-				if (info.globalExports.has(directExport)) {
-					return directExport;
 				}
 				const name = info.internalNames.get(directExport);
 				if (!name) {
@@ -238,23 +296,23 @@ const getFinalName = (
 						)}" has no internal name`
 					);
 				}
-				return name;
+				return `${name}${propertyAccess(exportName, 1)}`;
 			}
-			const reexport = info.reexportMap.get(exportName);
+			const reexport = info.reexportMap.get(exportId);
 			if (reexport) {
 				if (alreadyVisited.has(reexport)) {
 					throw new Error(
 						`Circular reexports ${Array.from(
 							alreadyVisited,
 							e =>
-								`"${e.module.readableIdentifier(requestShortener)}".${
+								`"${e.module.readableIdentifier(
-									e.exportName
+									requestShortener
-								}`
+								)}".${e.exportName.join(".")}`
 						).join(
 							" --> "
 						)} -(circular)-> "${reexport.module.readableIdentifier(
 							requestShortener
-						)}".${reexport.exportName}`
+						)}".${reexport.exportName.join(".")}`
 					);
 				}
 				alreadyVisited.add(reexport);
@@ -264,7 +322,7 @@ const getFinalName = (
 					return getFinalName(
 						moduleGraph,
 						refInfo,
-						reexport.exportName,
+						[...reexport.exportName, ...exportName.slice(1)],
 						moduleToInfoMap,
 						requestShortener,
 						asCall,
@@ -281,7 +339,10 @@ const getFinalName = (
 					.filter(name => name !== true)
 					.join(" ")}, ` +
 				`known reexports: ${Array.from(info.reexportMap.keys()).join(" ")})`;
-			return `${Template.toNormalComment(problem)} undefined`;
+			return `${Template.toNormalComment(problem)} undefined${propertyAccess(
+				exportName,
+				1
+			)}`;
 		}
 		case "external": {
 			const importedModule = info.module;
@@ -700,17 +761,6 @@ class ConcatenatedModule extends Module {
 						}
 					}
 				}
-
-				// add exported globals
-				const variables = new Set();
-				for (const variable of info.moduleScope.variables) {
-					variables.add(variable.name);
-				}
-				for (const [, variable] of info.exportMap) {
-					if (!variables.has(variable)) {
-						info.globalExports.add(variable);
-					}
-				}
 			}
 		}
 
@@ -823,10 +873,12 @@ class ConcatenatedModule extends Module {
 						const referencedModule = modulesWithInfo[+match[1]];
 						let exportName;
 						if (match[2] === "ns") {
-							exportName = true;
+							exportName = [];
 						} else {
 							const exportData = match[2];
-							exportName = Buffer.from(exportData, "hex").toString("utf-8");
+							exportName = JSON.parse(
+								Buffer.from(exportData, "hex").toString("utf-8")
+							);
 						}
 						const asCall = !!match[3];
 						const strictHarmonyModule = !!match[4];
@@ -850,7 +902,10 @@ class ConcatenatedModule extends Module {
 		const result = new ConcatSource();
 
 		// add harmony compatibility flag (must be first because of possible circular dependencies)
-		if (moduleGraph.getExportsInfo(this).otherExportsInfo.used !== false) {
+		if (
+			moduleGraph.getExportsInfo(this).otherExportsInfo.used !==
+			UsageState.Unused
+		) {
 			result.add(
 				runtimeTemplate.defineEsModuleFlagStatement({
 					exportsArgument: this.exportsArgument,
@@ -985,7 +1040,9 @@ class ConcatenatedModule extends Module {
 			let result;
 			switch (info.type) {
 				case "concatenated": {
+					/** @type {Map<string | true, string>} */
 					const exportMap = new Map();
+					/** @type {Map<string, ReexportInfo>} */
 					const reexportMap = new Map();
 					for (const dep of info.module.dependencies) {
 						if (dep instanceof HarmonyExportSpecifierDependency) {
@@ -1000,21 +1057,13 @@ class ConcatenatedModule extends Module {
 							dep instanceof HarmonyExportImportedSpecifierDependency
 						) {
 							const exportName = dep.name;
-							const importName = dep.getId(moduleGraph);
+							const importNames = dep.getIds(moduleGraph);
 							const importedModule = moduleGraph.getModule(dep);
-							if (exportName && importName) {
+							if (exportName) {
 								if (!reexportMap.has(exportName)) {
 									reexportMap.set(exportName, {
 										module: importedModule,
-										exportName: importName,
+										exportName: importNames,
-										dependency: dep
-									});
-								}
-							} else if (exportName) {
-								if (!reexportMap.has(exportName)) {
-									reexportMap.set(exportName, {
-										module: importedModule,
-										exportName: true,
 										dependency: dep
 									});
 								}
@@ -1030,7 +1079,7 @@ class ConcatenatedModule extends Module {
 										if (!reexportMap.has(name)) {
 											reexportMap.set(name, {
 												module: importedModule,
-												exportName: name,
+												exportName: [name],
 												dependency: dep
 											});
 										}
@@ -1049,7 +1098,6 @@ class ConcatenatedModule extends Module {
 						globalScope: undefined,
 						moduleScope: undefined,
 						internalNames: new Map(),
-						globalExports: new Set(),
 						exportMap: exportMap,
 						reexportMap: reexportMap,
 						hasNamespaceObject: false,
@@ -1269,15 +1317,17 @@ class HarmonyImportSpecifierDependencyConcatenatedTemplate extends DependencyTem
 		const strictFlag = parentModule.buildMeta.strictHarmonyModule
 			? "_strict"
 			: "";
-		const id = dep.getId(moduleGraph);
+		const ids = dep.getIds(moduleGraph);
-		if (id === null) {
+		if (ids.length === 0) {
 			content = `__WEBPACK_MODULE_REFERENCE__${info.index}_ns${strictFlag}__`;
-		} else if (dep.namespaceObjectAsContext) {
+		} else if (dep.namespaceObjectAsContext && ids.length === 1) {
 			content = `__WEBPACK_MODULE_REFERENCE__${
 				info.index
-			}_ns${strictFlag}__[${JSON.stringify(id)}]`;
+			}_ns${strictFlag}__${propertyAccess(ids)}`;
 		} else {
-			const exportData = Buffer.from(id, "utf-8").toString("hex");
+			const exportData = Buffer.from(JSON.stringify(ids), "utf-8").toString(
+				"hex"
+			);
 			content = `__WEBPACK_MODULE_REFERENCE__${
 				info.index
 			}_${exportData}${callFlag}${strictFlag}__`;
@@ -1398,7 +1448,7 @@ class HarmonyExportImportedSpecifierDependencyConcatenatedTemplate extends Depen
 	/**
 	 * @typedef {Object} GetExportsResultItem
 	 * @property {string} name
-	 * @property {string | true} id
+	 * @property {string[]} ids
 	 */
 
 	/**
@@ -1408,13 +1458,13 @@ class HarmonyExportImportedSpecifierDependencyConcatenatedTemplate extends Depen
 	 */
 	getExports(dep, { moduleGraph }) {
 		const importModule = moduleGraph.getModule(dep);
-		const id = dep.getId(moduleGraph);
+		const ids = dep.getIds(moduleGraph);
-		if (id) {
+		if (ids.length > 0) {
 			// export { named } from "module"
 			return [
 				{
 					name: dep.name,
-					id
+					ids
 				}
 			];
 		}
@@ -1423,7 +1473,7 @@ class HarmonyExportImportedSpecifierDependencyConcatenatedTemplate extends Depen
 			return [
 				{
 					name: dep.name,
-					id: true
+					ids: []
 				}
 			];
 		}
@@ -1435,7 +1485,7 @@ class HarmonyExportImportedSpecifierDependencyConcatenatedTemplate extends Depen
 				.map(exp => {
 					return {
 						name: exp,
-						id: exp
+						ids: [exp]
 					};
 				});
 		}
@@ -1465,7 +1515,7 @@ class HarmonyExportImportedSpecifierDependencyConcatenatedTemplate extends Depen
 				if (!used) {
 					initFragments.push(
 						new InitFragment(
-							`/* unused concated harmony import ${dep.name} */\n`,
+							`/* unused concated harmony import ${def.name} */\n`,
 							InitFragment.STAGE_HARMONY_EXPORTS,
 							1
 						)
@@ -1476,12 +1526,15 @@ class HarmonyExportImportedSpecifierDependencyConcatenatedTemplate extends Depen
 				const strictFlag = module.buildMeta.strictHarmonyModule
 					? "_strict"
 					: "";
-				if (def.id === true) {
+				if (def.ids.length === 0) {
 					finalName = `__WEBPACK_MODULE_REFERENCE__${
 						info.index
 					}_ns${strictFlag}__`;
 				} else {
-					const exportData = Buffer.from(def.id, "utf-8").toString("hex");
+					const exportData = Buffer.from(
+						JSON.stringify(def.ids),
+						"utf-8"
+					).toString("hex");
 					finalName = `__WEBPACK_MODULE_REFERENCE__${
 						info.index
 					}_${exportData}${strictFlag}__`;

lib/optimize/SideEffectsFlagPlugin.js

@@ -104,11 +104,11 @@ class SideEffectsFlagPlugin {
 										if (!map) {
 											reexportMaps.set(module, (map = new Map()));
 										}
-										for (const [key, id] of mode.map) {
+										for (const [key, ids] of mode.map) {
-											if (!mode.checked.has(key)) {
+											if (ids.length > 0 && !mode.checked.has(key)) {
 												map.set(key, {
 													module: mode.getModule(),
-													exportName: id
+													exportName: ids[0]
 												});
 											}
 										}
@@ -147,15 +147,24 @@ class SideEffectsFlagPlugin {
 								(dep instanceof HarmonyImportSpecifierDependency &&
 									!dep.namespaceObjectAsContext)
 							) {
-								const mapping = map.get(dep.id);
+								// TODO improve for nested imports
-								if (mapping) {
+								const ids = dep.getIds(moduleGraph);
-									moduleGraph.updateModule(dep, mapping.module);
+								if (ids.length > 0) {
-									moduleGraph.addExplanation(
+									const mapping = map.get(ids[0]);
-										dep,
+									if (mapping) {
-										"(skipped side-effect-free modules)"
+										moduleGraph.updateModule(dep, mapping.module);
-									);
+										moduleGraph.addExplanation(
-									dep.setId(moduleGraph, mapping.exportName);
+											dep,
-									continue;
+											"(skipped side-effect-free modules)"
+										);
+										dep.setIds(
+											moduleGraph,
+											mapping.exportName
+												? [mapping.exportName, ...ids.slice(1)]
+												: ids.slice(1)
+										);
+										continue;
+									}
 								}
 							}
 						}

lib/util/propertyAccess.js

@@ -0,0 +1,25 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const SAFE_IDENTIFIER = /^[_a-zA-Z$][_a-zA-z$0-9]*$/;
+
+const propertyAccess = (properties, start = 0) => {
+	let str = "";
+	for (let i = start; i < properties.length; i++) {
+		const p = properties[i];
+		if (`${+p}` === p) {
+			str += `[${p}]`;
+		} else if (SAFE_IDENTIFIER.test(p)) {
+			str += `.${p}`;
+		} else {
+			str += `[${JSON.stringify(p)}]`;
+		}
+	}
+	return str;
+};
+
+module.exports = propertyAccess;

lib/wasm/WasmFinalizeExportsPlugin.js

@@ -47,7 +47,10 @@ class WasmFinalizeExportsPlugin {
 									const importedNames = ref.importedNames;
 
 									if (Array.isArray(importedNames)) {
-										importedNames.forEach(name => {
+										importedNames.forEach(nameOrNames => {
+											const name = Array.isArray(nameOrNames)
+												? nameOrNames[0]
+												: nameOrNames;
 											// 3. and uses a func with an incompatible JS signature
 											if (
 												Object.prototype.hasOwnProperty.call(

lib/wasm/WebAssemblyJavascriptGenerator.js

@@ -7,6 +7,7 @@
 
 const { RawSource } = require("webpack-sources");
 const Generator = require("../Generator");
+const { UsageState } = require("../ModuleGraph");
 const RuntimeGlobals = require("../RuntimeGlobals");
 const Template = require("../Template");
 const WebAssemblyExportImportedDependency = require("../dependencies/WebAssemblyExportImportedDependency");
@@ -148,12 +149,13 @@ class WebAssemblyJavascriptGenerator extends Generator {
 		);
 
 		const copyAllExports =
-			exportsInfo.otherExportsInfo.used === false && !needExportsCopy;
+			exportsInfo.otherExportsInfo.used === UsageState.Unused &&
+			!needExportsCopy;
 
 		// need these globals
 		runtimeRequirements.add(RuntimeGlobals.module);
 		runtimeRequirements.add(RuntimeGlobals.wasmInstances);
-		if (exportsInfo.otherExportsInfo.used !== false) {
+		if (exportsInfo.otherExportsInfo.used !== UsageState.Unused) {
 			runtimeRequirements.add(RuntimeGlobals.makeNamespaceObject);
 			runtimeRequirements.add(RuntimeGlobals.exports);
 		}
@@ -170,7 +172,7 @@ class WebAssemblyJavascriptGenerator extends Generator {
 					module.moduleArgument
 				}.i];`,
 
-				exportsInfo.otherExportsInfo.used !== false
+				exportsInfo.otherExportsInfo.used !== UsageState.Unused
 					? `${RuntimeGlobals.makeNamespaceObject}(${module.exportsArgument});`
 					: "",
 

test/__snapshots__/StatsTestCases.test.js.snap

@@ -430,7 +430,7 @@ Child all:
 `;
 
 exports[`StatsTestCases should print correct stats for chunk-module-id-range 1`] = `
-"Hash: 72e3b32fcbbc550ae041
+"Hash: 4b7df25b6465c464acfe
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
 PublicPath: (none)
@@ -503,10 +503,10 @@ Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
 PublicPath: (none)
               Asset       Size       Chunks             Chunk Names
-     b_js.bundle.js  370 bytes       {b_js}  [emitted]
+     b_js.bundle.js  364 bytes       {b_js}  [emitted]
-          bundle.js   8.23 KiB       {main}  [emitted]  main
+          bundle.js   8.22 KiB       {main}  [emitted]  main
-     c_js.bundle.js  579 bytes       {c_js}  [emitted]
+     c_js.bundle.js  573 bytes       {c_js}  [emitted]
-d_js-e_js.bundle.js  772 bytes  {d_js-e_js}  [emitted]
+d_js-e_js.bundle.js  760 bytes  {d_js-e_js}  [emitted]
 Entrypoint main = bundle.js
 chunk {b_js} b_js.bundle.js 22 bytes <{main}> [rendered]
     > ./b [./index.js] ./index.js 2:0-16
@@ -618,26 +618,26 @@ Entrypoint entry-1 = vendor-1.js entry-1.js
 `;
 
 exports[`StatsTestCases should print correct stats for commons-plugin-issue-4980 1`] = `
-"Hash: 53f13412753ee8bb3d387595bab0743d3d05a312
+"Hash: ada681c866c95e0132eff2c9453ed201db5580c2
 Child
-    Hash: 53f13412753ee8bb3d38
+    Hash: ada681c866c95e0132ef
     Time: Xms
     Built at: Thu Jan 01 1970 00:00:00 GMT
                              Asset       Size  Chunks             Chunk Names
-       app.269cd87fa0cbcfa98d1b.js   6.65 KiB   {143}  [emitted]  app
+       app.72745ea3abc585e103e5.js   6.69 KiB   {143}  [emitted]  app
-    vendor.37b166c3b85bfb1caf5f.js  616 bytes   {736}  [emitted]  vendor
+    vendor.22698e25646290b0dcc1.js  616 bytes   {736}  [emitted]  vendor
-    Entrypoint app = vendor.37b166c3b85bfb1caf5f.js app.269cd87fa0cbcfa98d1b.js
+    Entrypoint app = vendor.22698e25646290b0dcc1.js app.72745ea3abc585e103e5.js
     [117] ./entry-1.js + 2 modules 190 bytes {143} [built]
     [381] ./constants.js 87 bytes {736} [built]
         + 4 hidden modules
 Child
-    Hash: 7595bab0743d3d05a312
+    Hash: f2c9453ed201db5580c2
     Time: Xms
     Built at: Thu Jan 01 1970 00:00:00 GMT
                              Asset       Size  Chunks             Chunk Names
-       app.3ec38d64835ee4418bb3.js   6.67 KiB   {143}  [emitted]  app
+       app.eee68844dbd56e9ed525.js    6.7 KiB   {143}  [emitted]  app
-    vendor.37b166c3b85bfb1caf5f.js  616 bytes   {736}  [emitted]  vendor
+    vendor.22698e25646290b0dcc1.js  616 bytes   {736}  [emitted]  vendor
-    Entrypoint app = vendor.37b166c3b85bfb1caf5f.js app.3ec38d64835ee4418bb3.js
+    Entrypoint app = vendor.22698e25646290b0dcc1.js app.eee68844dbd56e9ed525.js
     [381] ./constants.js 87 bytes {736} [built]
     [655] ./entry-2.js + 2 modules 197 bytes {143} [built]
         + 4 hidden modules"
@@ -1087,7 +1087,7 @@ chunk {trees} trees.js (trees) 71 bytes [rendered]
 `;
 
 exports[`StatsTestCases should print correct stats for import-context-filter 1`] = `
-"Hash: 49f607faddf9699cbef8
+"Hash: 99ab54650501715e52b3
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
    Asset       Size  Chunks             Chunk Names
@@ -1453,7 +1453,7 @@ If you don't want to include a polyfill, you can use an empty module like this:
 `;
 
 exports[`StatsTestCases should print correct stats for module-reasons 1`] = `
-"Hash: 9e3985f832f4d566fdbb
+"Hash: 9757fb3da1f7b8f77bbb
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
   Asset      Size  Chunks             Chunk Names
@@ -1476,7 +1476,7 @@ Entrypoint main = main.js
  [10] ./index.js 19 bytes {179} [built]
 [195] ./not-existing.js 26 bytes {179} [built]
 [587] ./inner.js 53 bytes {179} [built]
-[636] ./parse-error.js 167 bytes {179} [built] [failed] [1 error]
+[636] ./parse-error.js 27 bytes {179} [built] [failed] [1 error]
 
 ERROR in ./not-existing.js 1:0-25
 Module not found: Error: Can't resolve 'does-not-exist' in 'Xdir/module-trace-disabled-in-error'
@@ -1501,7 +1501,7 @@ Entrypoint main = main.js
  [10] ./index.js 19 bytes {179} [built]
 [195] ./not-existing.js 26 bytes {179} [built]
 [587] ./inner.js 53 bytes {179} [built]
-[636] ./parse-error.js 167 bytes {179} [built] [failed] [1 error]
+[636] ./parse-error.js 27 bytes {179} [built] [failed] [1 error]
 
 ERROR in ./not-existing.js 1:0-25
 Module not found: Error: Can't resolve 'does-not-exist' in 'Xdir/module-trace-enabled-in-error'
@@ -1686,7 +1686,7 @@ exports[`StatsTestCases should print correct stats for parse-error 1`] = `
 main.js  4.34 KiB   {179}  main
 Entrypoint main = main.js
 [535] ./index.js + 1 modules 35 bytes {179} [built]
-[996] ./b.js 169 bytes {179} [built] [failed] [1 error]
+[996] ./b.js 55 bytes {179} [built] [failed] [1 error]
     + 4 hidden modules
 
 ERROR in ./b.js 6:7
@@ -2289,7 +2289,7 @@ Entrypoint e2 = runtime.js e2.js"
 `;
 
 exports[`StatsTestCases should print correct stats for scope-hoisting-bailouts 1`] = `
-"Hash: ac1889126d1918a36204
+"Hash: b4a9cfa089ce3732efc5
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
 Entrypoint index = index.js
@@ -2318,9 +2318,9 @@ Entrypoint entry = entry.js
 `;
 
 exports[`StatsTestCases should print correct stats for scope-hoisting-multi 1`] = `
-"Hash: 0b46c17cd9c6ad0fbfb2a8733d1161800e5d8cb5
+"Hash: d4c3cd048bdc678bb92437745aea03a16f764c79
 Child
-    Hash: 0b46c17cd9c6ad0fbfb2
+    Hash: d4c3cd048bdc678bb924
     Time: Xms
     Built at: Thu Jan 01 1970 00:00:00 GMT
     Entrypoint first = vendor.js first.js
@@ -2338,7 +2338,7 @@ Child
     [965] ./vendor.js 25 bytes {736} [built]
         + 10 hidden modules
 Child
-    Hash: a8733d1161800e5d8cb5
+    Hash: 37745aea03a16f764c79
     Time: Xms
     Built at: Thu Jan 01 1970 00:00:00 GMT
     Entrypoint first = vendor.js first.js
@@ -2365,11 +2365,11 @@ Child
 `;
 
 exports[`StatsTestCases should print correct stats for side-effects-issue-7428 1`] = `
-"Hash: 8d106e0a6c9f100fb26f
+"Hash: 8871bd720c1e20111581
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
   Asset       Size  Chunks             Chunk Names
-   1.js  481 bytes     {1}  [emitted]
+   1.js  478 bytes     {1}  [emitted]
 main.js   10.1 KiB     {0}  [emitted]  main
 Entrypoint main = main.js
 [0] ./main.js + 1 modules 231 bytes {0} [built]
@@ -2414,7 +2414,7 @@ Entrypoint main = main.js
 `;
 
 exports[`StatsTestCases should print correct stats for side-effects-simple-unused 1`] = `
-"Hash: aabd6d1544eb169e22e5
+"Hash: 589af6828de7c047d0c5
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
   Asset      Size  Chunks             Chunk Names
@@ -2450,7 +2450,7 @@ exports[`StatsTestCases should print correct stats for simple 1`] = `
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
     Asset      Size  Chunks             Chunk Names
-bundle.js  1.56 KiB  {main}  [emitted]  main
+bundle.js  1.55 KiB  {main}  [emitted]  main
 Entrypoint main = bundle.js
 [./index.js] 1 bytes {main} [built]"
 `;
@@ -3446,7 +3446,7 @@ chunk {794} default/async-a.js (async-a) 134 bytes <{179}> [rendered]
 `;
 
 exports[`StatsTestCases should print correct stats for tree-shaking 1`] = `
-"Hash: a74d3a7695fab0e2d9aa
+"Hash: 9f0d95b08ca5afeee1fe
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
     Asset     Size  Chunks             Chunk Names
@@ -3507,28 +3507,28 @@ WARNING in Terser Plugin: Dropping unused function someUnRemoteUsedFunction5 [./
 `;
 
 exports[`StatsTestCases should print correct stats for wasm-explorer-examples-sync 1`] = `
-"Hash: e6c683371cb4c4354398
+"Hash: 48cd6bb29a775ac0f234
 Time: Xms
 Built at: Thu Jan 01 1970 00:00:00 GMT
                            Asset       Size  Chunks             Chunk Names
-00885349ebe3dd903faa.module.wasm  125 bytes   {325}  [emitted]
+10d1272d7cf8dafe2f3a.module.wasm  225 bytes   {780}  [emitted]
                    230.bundle.js  430 bytes   {230}  [emitted]
-                   325.bundle.js   3.93 KiB   {325}  [emitted]
+                   325.bundle.js    3.9 KiB   {325}  [emitted]
                    526.bundle.js  329 bytes   {526}  [emitted]
                    780.bundle.js  842 bytes   {780}  [emitted]
-7d7a509c17179e42766a.module.wasm   94 bytes   {325}  [emitted]
+7eee906d414e0947ebbf.module.wasm  132 bytes   {780}  [emitted]
+94b864234c573663c221.module.wasm   94 bytes   {325}  [emitted]
                     99.bundle.js  428 bytes    {99}  [emitted]
+a160192b41d0463ac226.module.wasm  131 bytes   {230}  [emitted]
                        bundle.js   13.5 KiB   {520}  [emitted]  main-1df31ce3
-cfd5ebf998e67f7103a2.module.wasm  510 bytes    {99}  [emitted]
+d95036d90a8b92bc2692.module.wasm  510 bytes    {99}  [emitted]
-e94fc8ba836bfd2c6038.module.wasm  131 bytes   {230}  [emitted]
+ff9c5233b4dbdf834f6f.module.wasm  125 bytes   {325}  [emitted]
-f8f99fabd0c63ad1c730.module.wasm  225 bytes   {780}  [emitted]
-fea68b3453f2f8fdfeed.module.wasm  132 bytes   {780}  [emitted]
 Entrypoint main = bundle.js
-chunk {99} 99.bundle.js, cfd5ebf998e67f7103a2.module.wasm 100 bytes (javascript) 531 bytes (webassembly) [rendered]
+chunk {99} 99.bundle.js, d95036d90a8b92bc2692.module.wasm 100 bytes (javascript) 531 bytes (webassembly) [rendered]
  [99] ./duff.wasm 100 bytes (javascript) 531 bytes (webassembly) {99} [built]
-chunk {230} 230.bundle.js, e94fc8ba836bfd2c6038.module.wasm 100 bytes (javascript) 156 bytes (webassembly) [rendered]
+chunk {230} 230.bundle.js, a160192b41d0463ac226.module.wasm 100 bytes (javascript) 156 bytes (webassembly) [rendered]
  [230] ./Q_rsqrt.wasm 100 bytes (javascript) 156 bytes (webassembly) {230} [built]
-chunk {325} 325.bundle.js, 7d7a509c17179e42766a.module.wasm, 00885349ebe3dd903faa.module.wasm 1.6 KiB (javascript) 274 bytes (webassembly) [rendered]
+chunk {325} 325.bundle.js, 94b864234c573663c221.module.wasm, ff9c5233b4dbdf834f6f.module.wasm 1.6 KiB (javascript) 274 bytes (webassembly) [rendered]
  [287] ./popcnt.wasm 100 bytes (javascript) 120 bytes (webassembly) {325} [built]
  [325] ./tests.js 1.4 KiB {325} [built]
  [819] ./testFunction.wasm 100 bytes (javascript) 154 bytes (webassembly) {325} [built]
@@ -3537,7 +3537,7 @@ chunk {520} bundle.js (main-1df31ce3) 586 bytes (javascript) 6.75 KiB (runtime)
      + 7 hidden chunk modules
 chunk {526} 526.bundle.js 34 bytes [rendered] split chunk (cache group: defaultVendors)
  [526] ./node_modules/env.js 34 bytes {526} [built]
-chunk {780} 780.bundle.js, fea68b3453f2f8fdfeed.module.wasm, f8f99fabd0c63ad1c730.module.wasm 205 bytes (javascript) 444 bytes (webassembly) [rendered]
+chunk {780} 780.bundle.js, 7eee906d414e0947ebbf.module.wasm, 10d1272d7cf8dafe2f3a.module.wasm 205 bytes (javascript) 444 bytes (webassembly) [rendered]
  [143] ./fact.wasm 100 bytes (javascript) 154 bytes (webassembly) {780} [built]
  [151] ./fast-math.wasm 105 bytes (javascript) 290 bytes (webassembly) {780} [built]
  [10] ./index.js 586 bytes {520} [built]

test/cases/parsing/harmony-deep-exports/counter.js

@@ -0,0 +1,8 @@
+export let counter = 0;
+export const increment = () => {
+	counter++;
+};
+export function reset() {
+	counter = 0;
+};
+export const unusedExport = 42;

test/cases/parsing/harmony-deep-exports/index.js

@@ -0,0 +1,24 @@
+import * as C from "./reexport-namespace";
+import { counter } from "./reexport-namespace";
+import * as C2 from "./reexport-namespace-again";
+
+it("should allow to reexport namespaces 1", () => {
+	counter.reset();
+	expect(counter.counter).toBe(0);
+	counter.increment();
+	expect(counter.counter).toBe(1);
+});
+
+it("should allow to reexport namespaces 2", () => {
+	C.counter.reset();
+	expect(C.counter.counter).toBe(0);
+	C.counter.increment();
+	expect(C.counter.counter).toBe(1);
+});
+
+it("should allow to reexport namespaces 3", () => {
+	C2.CC.counter.reset();
+	expect(C2.CC.counter.counter).toBe(0);
+	C2.CC.counter.increment();
+	expect(C2.CC.counter.counter).toBe(1);
+});

test/cases/parsing/harmony-deep-exports/reexport-namespace-again.js

@@ -0,0 +1,2 @@
+import * as CC from "./reexport-namespace";
+export { CC };

test/cases/parsing/harmony-deep-exports/reexport-namespace.js

@@ -0,0 +1,2 @@
+import * as counter from "./counter";
+export { counter };

test/configCases/deep-scope-analysis/remove-export-scope-hoisting/webpack.config.js

@@ -15,10 +15,12 @@ module.exports = {
 						ref.module &&
 						ref.module.identifier().endsWith("reference.js") &&
 						Array.isArray(ref.importedNames) &&
-						ref.importedNames.includes("unused")
+						ref.importedNames.some(
+							names => names.length === 1 && names[0] === "unused"
+						)
 					) {
 						const newExports = ref.importedNames.filter(
-							item => item !== "unused"
+							names => names.length !== 1 || names[0] !== "unused"
 						);
 						return new DependencyReference(
 							() => ref.module,

test/configCases/deep-scope-analysis/remove-export/webpack.config.js

@@ -15,10 +15,12 @@ module.exports = {
 						ref.module &&
 						ref.module.identifier().endsWith("reference.js") &&
 						Array.isArray(ref.importedNames) &&
-						ref.importedNames.includes("unused")
+						ref.importedNames.some(
+							names => names.length === 1 && names[0] === "unused"
+						)
 					) {
 						const newExports = ref.importedNames.filter(
-							item => item !== "unused"
+							names => names.length !== 1 || names[0] !== "unused"
 						);
 						return new DependencyReference(
 							() => ref.module,

test/configCases/parsing/harmony-this-concat/abc.js

@@ -1,14 +1,63 @@
 function returnThis() {
-	if(typeof this === "undefined") return "undefined";
+	if (typeof this === "undefined") return "undefined";
 	return this;
 }
 
 var a = returnThis;
 var b = returnThis;
 
-export {
+export { a, b };
-	a,
+
-	b
+export const that = this;
+export const returnThisArrow = () => this;
+export const returnThisMember = () => this.a;
+
+export class C {
+	constructor() {
+		this.x = "bar";
+	}
+	foo() {
+		return this.x;
+	}
+	bar(x = this.x) {
+		return x;
+	}
+}
+
+export const extendThisClass = () => {
+	return class extends this.Buffer {};
+};
+
+export function D() {
+	this.prop = () => "ok";
+}
+
+// See https://github.com/webpack/webpack/issues/6379
+export const E = {
+	x: "bar",
+	foo(x = this.x) {
+		return x;
+	}
+};
+
+// See https://github.com/webpack/webpack/issues/6967
+export const F = function() {
+	return this;
+}.call("ok");
+
+export function f1(x = this.x) {
+	return x;
+}
+
+export const f2 = function(x = this.x) {
+	return x;
+};
+
+export const f3 = (x = this) => x;
+
+export function G(x) {
+	this.x = x;
+	this.getX = (y = this.x) => y;
 }
 
 export default returnThis;

test/configCases/parsing/harmony-this-concat/index.js

@@ -1,11 +1,45 @@
 "use strict";
 
-import d, {a, b as B} from "./abc";
+import {extendThisClass, returnThisArrow, returnThisMember, that} from "./abc";
+import d, {a, b as B, C as _C, D as _D, E, F, f1, f2, f3, G} from "./abc";
+import {bindThis, callThis, applyThis} from "./issue-7213";
 
 import * as abc from "./abc";
 
-function x() { throw new Error("should not be executed"); }
+it("should have this = undefined on harmony modules", () => {
-it("should have this = undefined on imported non-strict functions", function() {
+	expect((typeof that)).toBe("undefined");
+	expect((typeof abc.that)).toBe("undefined");
+	expect((typeof returnThisArrow())).toBe("undefined");
+	expect((typeof abc.returnThisArrow())).toBe("undefined");
+	expect(function() {
+		returnThisMember();
+	}).toThrowError();
+	expect(function() {
+		abc.returnThisMember();
+	}).toThrowError();
+	expect(function() {
+		extendThisClass();
+	}).toThrowError();
+});
+
+it("should not break classes and functions", () => {
+	expect((new _C).foo()).toBe("bar");
+	expect((new _C).bar()).toBe("bar");
+	expect((new _D).prop()).toBe("ok");
+	expect(E.foo()).toBe("bar");
+	expect(F).toBe("ok");
+	expect(f1.call({x: "f1"})).toBe("f1");
+	expect(f2.call({x: "f2"})).toBe("f2");
+	expect(f3.call("f3")).toBe(undefined);
+	expect(f3()).toBe(undefined);
+	expect((new G("ok")).getX()).toBe("ok");
+});
+
+function x() {
+	throw new Error("should not be executed");
+}
+
+it("should have this = undefined on imported non-strict functions", () => {
 	x
 	expect(d()).toBe("undefined");
 	x
@@ -13,17 +47,17 @@ it("should have this = undefined on imported non-strict functions", function() {
 	x
 	expect(B()).toBe("undefined");
 	x
-	expect(abc.a()).toMatchObject({});
+	expect(abc.a()).toBeTypeOf("object");
 	x
 	var thing = abc.a();
-	expect(Object.keys(thing)).toEqual(["a", "b", "default"]);
+	expect(Object.keys(thing)).toEqual(Object.keys(abc));
 });
 
 import C2, { C } from "./new";
 
 import * as New from "./new";
 
-it("should be possible to use new correctly", function() {
+it("should be possible to use new correctly", () => {
 	x
 	expect(new C()).toEqual({ok: true});
 	x
@@ -31,3 +65,9 @@ it("should be possible to use new correctly", function() {
 	x
 	expect(new New.C()).toEqual({ok: true});
 });
+
+it("should not break Babel arrow function transform", () => {
+	expect(bindThis()).toBe(undefined);
+	expect(callThis).toBe(undefined);
+	expect(applyThis).toBe(undefined);
+});

test/configCases/parsing/harmony-this-concat/issue-7213.js

@@ -0,0 +1,20 @@
+// This helper is taken from Babel
+function _newArrowCheck(innerThis, boundThis) {
+	if (innerThis !== boundThis) {
+		throw new TypeError("Cannot instantiate an arrow function");
+	}
+}
+
+let _this = this;
+export let bindThis = function() {
+	_newArrowCheck(this, _this);
+	return this
+}.bind(this);
+
+export let callThis = function() {
+	return this
+}.call(this)
+
+export let applyThis = function() {
+	return this
+}.apply(this)

test/configCases/parsing/harmony-this-concat/webpack.config.js

@@ -2,6 +2,5 @@ var webpack = require("../../../../");
 module.exports = {
 	module: {
 		strictThisContextOnImports: true
-	},
+	}
-	plugins: [new webpack.optimize.ModuleConcatenationPlugin()]
 };

test/configCases/parsing/harmony-this/webpack.config.js

@@ -1,5 +1,8 @@
 module.exports = {
 	module: {
 		strictThisContextOnImports: true
+	},
+	optimization: {
+		concatenateModules: false
 	}
 };