fix: ASI in concatenated module only when necessary

lib/optimize/ConcatenatedModule.js

@@ -146,6 +146,7 @@ if (!ReferencerClass.prototype.PropertyDefinition) {
  * @property {string | undefined} interopNamespaceObject2Name
  * @property {boolean} interopDefaultAccessUsed
  * @property {string | undefined} interopDefaultAccessName
+ * @property {boolean} prefixAsi
  */
 
 /**
@@ -172,6 +173,7 @@ if (!ReferencerClass.prototype.PropertyDefinition) {
 
 /** @typedef {Set<string>} UsedNames */
 
+const CHARS_REQUIRING_SEMICOLON = ["[", "(", "+", "-", "/"];
 const RESERVED_NAMES = new Set(
 	[
 		// internal names (should always be renamed)
@@ -1467,6 +1469,12 @@ class ConcatenatedModule extends Module {
 						);
 						const r = /** @type {Range} */ (reference.identifier.range);
 						const source = info.source;
+
+						// in case finalName starts with a character that requires a semicolon
+						if (CHARS_REQUIRING_SEMICOLON.includes(finalName[0])) {
+							info.prefixAsi = true;
+						}
+
 						// range is extended by 2 chars to cover the appended "._"
 						source.replace(r[0], r[1] + 1, finalName);
 					}
@@ -1660,10 +1668,13 @@ ${defineGetters}`
 			switch (info.type) {
 				case "concatenated": {
 					result.add(
-						`\n;// CONCATENATED MODULE: ${info.module.readableIdentifier(
+						`\n// CONCATENATED MODULE: ${info.module.readableIdentifier(
 							requestShortener
 						)}\n`
 					);
+					if (/** @type {ConcatenatedModuleInfo} */ (rawInfo).prefixAsi) {
+						result.add(";");
+					}
 					result.add(info.source);
 					if (info.chunkInitFragments) {
 						for (const f of info.chunkInitFragments) chunkInitFragments.push(f);
@@ -1825,6 +1836,7 @@ ${defineGetters}`
 				info.chunkInitFragments = chunkInitFragments;
 				info.globalScope = globalScope;
 				info.moduleScope = moduleScope;
+				info.prefixAsi = CHARS_REQUIRING_SEMICOLON.includes(code[0]);
 			} catch (err) {
 				/** @type {Error} */
 				(err).message +=
@@ -1873,7 +1885,8 @@ ${defineGetters}`
 							interopNamespaceObject2Used: false,
 							interopNamespaceObject2Name: undefined,
 							interopDefaultAccessUsed: false,
-							interopDefaultAccessName: undefined
+							interopDefaultAccessName: undefined,
+							prefixAsi: false
 						};
 						break;
 					case "external":

test/configCases/scope-hoisting/issue-11897/webpack.config.js

@@ -0,0 +1,6 @@
+/** @type {import("../../../../").Configuration} */
+module.exports = {
+	optimization: {
+		concatenateModules: true
+	}
+};