Make sure it's a real module when choosing for ModuleConcatenation

fixes #5095

lib/optimize/ModuleConcatenationPlugin.js

@@ -7,6 +7,7 @@
 const HarmonyImportDependency = require("../dependencies/HarmonyImportDependency");
 const ConcatenatedModule = require("./ConcatenatedModule");
 const HarmonyExportImportedSpecifierDependency = require("../dependencies/HarmonyExportImportedSpecifierDependency");
+const HarmonyCompatibilityDependency = require("../dependencies/HarmonyCompatibilityDependency");
 
 class ModuleConcatenationPlugin {
 	constructor(options) {
@@ -39,7 +40,7 @@ class ModuleConcatenationPlugin {
 				const possibleInners = new Set();
 				for(const module of modules) {
 					// Only harmony modules are valid for optimization
-					if(!module.meta || !module.meta.harmonyModule) {
+					if(!module.meta || !module.meta.harmonyModule || !module.dependencies.some(d => d instanceof HarmonyCompatibilityDependency)) {
 						continue;
 					}
 

test/configCases/scope-hoisting/dll-plugin/index.js

@@ -0,0 +1,5 @@
+import value from "dll/module";
+
+it("should not scope hoist delegated modules", function() {
+	value.should.be.eql("ok");
+});

test/configCases/scope-hoisting/dll-plugin/webpack.config.js

@@ -0,0 +1,19 @@
+var webpack = require("../../../../");
+module.exports = {
+	plugins: [
+		new webpack.DllReferencePlugin({
+			name: "function(id) { return {default: 'ok'}; }",
+			scope: "dll",
+			content: {
+				"./module": {
+					id: 1,
+					meta: {
+						harmonyModule: true
+					},
+					exports: ["default"]
+				}
+			}
+		}),
+		new webpack.optimize.ModuleConcatenationPlugin()
+	]
+};