diff --git a/lib/Compilation.js b/lib/Compilation.js
index 607be3124..9326a2dbc 100644
--- a/lib/Compilation.js
+++ b/lib/Compilation.js
@@ -461,17 +461,16 @@ class Compilation {
 
 	/**
 	 * @param {Module} module module to be added that was created
-	 * @param {any=} cacheGroup cacheGroup it is apart of
 	 * @returns {Module} returns the module in the compilation,
 	 * it could be the passed one (if new), or an already existing in the compilation
 	 */
-	addModule(module, cacheGroup) {
+	addModule(module) {
 		const identifier = module.identifier();
 		const alreadyAddedModule = this._modules.get(identifier);
 		if (alreadyAddedModule) {
 			return alreadyAddedModule;
 		}
-		const cacheName = (cacheGroup || "m") + identifier;
+		const cacheName = "m" + identifier;
 		if (this.cache && this.cache[cacheName]) {
 			const cacheModule = this.cache[cacheName];