@@ -0,0 +1,5 @@
+---
+"webpack": patch
+---
+
+Keep a strict ES module importer's interop for lazily compiled modules.
@@ -60,6 +60,7 @@ const getMatchModuleGlobCondition = memoize(
 /** @import RequestShortener from "../util/RequestShortener" */
 /** @import { ResolverWithOptions } from "../resolve/ResolverFactory" */
 /** @import ESMImportDependency from "../dependencies/esm/ESMImportDependency" */
+/** @import { JavascriptModuleBuildMeta } from "../javascript/JavascriptModule" */
 /** @import Hash from "../util/Hash" */
 /** @import { InputFileSystem } from "../fs/fs" */
 
@@ -235,8 +236,9 @@ class LazyCompilationProxyModule extends Module {
 	 * @param {ModuleResult["client"]} client client
 	 * @param {ModuleResult["data"]} data data
 	 * @param {ModuleResult["active"]} active true when active, otherwise false
+	 * @param {boolean} strict whether its importers are strict ES modules
 	 */
-	constructor(context, originalModule, request, client, data, active) {
+	constructor(context, originalModule, request, client, data, active, strict) {
 		super(
 			WEBPACK_MODULE_TYPE_LAZY_COMPILATION_PROXY,
 			context,
@@ -255,14 +257,16 @@ class LazyCompilationProxyModule extends Module {
 		this.data = data;
 		/** @type {boolean} */
 		this.active = active;
+		/** @type {boolean} */
+		this.strict = strict;
 	}
 
 	/**
 	 * Returns the unique identifier used to reference this module.
 	 * @returns {string} a unique identifier of the module
 	 */
 	identifier() {
-		return `${WEBPACK_MODULE_TYPE_LAZY_COMPILATION_PROXY}|${this.originalModule.identifier()}`;
+		return `${WEBPACK_MODULE_TYPE_LAZY_COMPILATION_PROXY}|${this.originalModule.identifier()}${this.strict ? "|strict" : ""}`;
 	}
 
 	/**
@@ -291,6 +295,7 @@ class LazyCompilationProxyModule extends Module {
 		this.client = m.client;
 		this.data = m.data;
 		this.active = m.active;
+		this.strict = m.strict;
 	}
 
 	/**
@@ -419,7 +424,7 @@ class LazyCompilationProxyModule extends Module {
 					module,
 					request: this.request,
 					dependency: dep,
-					strict: false, // TODO this should be inherited from the original module
+					strict: this.strict,
 					message: "import()",
 					runtimeRequirements,
 					originModule: this
@@ -622,14 +627,26 @@ class LazyCompilationPlugin {
 						const moduleInfo = backend.module(module);
 						if (!moduleInfo) return module;
 						const { client, data, active } = moduleInfo;
+						// The proxy builds the namespace its importers get, and a strict ES module
+						// importer needs another shape than a loose one, so each gets its own proxy.
+						const importer = compilation.moduleGraph.getParentModule(
+							resolveData.dependencies[0]
+						);
+						const strict = Boolean(
+							importer &&
+							importer.buildMeta &&
+							/** @type {JavascriptModuleBuildMeta} */ (importer.buildMeta)
+								.strictHarmonyModule
+						);
 
 						return new LazyCompilationProxyModule(
 							compiler.context,
 							module,
 							resolveData.request,
 							client,
 							data,
-							active
+							active,
+							strict
 						);
 					}
 				);
 
@@ -1280,8 +1280,7 @@ class MinifierVariable extends Variable {
 		/** @type {number} how an `export` naming it keeps its name, as `EXPORT_*` */
 		this.export = 0;
 		/** @type {string | null} the name mangling gives it */
-		// eslint-disable-next-line camelcase -- terser's name, which the printer reads
-		this.mangled_name = null;
+		this.mangledName = null;
 		/** @type {number} how many names read or write it, which the mangler gives the short names by */
 		this.referenceCount = 0;
 		/** @type {boolean} whether a name writes it, which a `SyntaxTree`'s analysis alone records */
@@ -1306,8 +1305,7 @@ class MinifierLabel {
 		/** @type {string} */
 		this.name = name;
 		/** @type {string | null} the name mangling gives it */
-		// eslint-disable-next-line camelcase -- terser's name, which the printer reads
-		this.mangled_name = null;
+		this.mangledName = null;
 		/** @type {MinifierLabel | null} */
 		this.parent = parent;
 		/** @type {number} where the mangler's label names stood when it named this one */
-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +"webpack": patch
 +---
++
 +Keep a strict ES module importer's interop for lazily compiled modules.