unite iteration through modules into one loop

lib/optimize/ConcatenatedModule.js

@@ -143,20 +143,29 @@ class ConcatenatedModule extends Module {
 		this.cacheable = modules.every(m => m.cacheable);
 		const modulesSet = new Set(modules);
 		this.reasons = rootModule.reasons.filter(reason => !modulesSet.has(reason.module));
-		this.dependencies = [];
 		this.meta = rootModule.meta;
-		this.dependenciesWarnings = modules.reduce((w, m) => m.dependenciesWarnings.forEach(x => w.push(x)), []);
-		this.dependenciesErrors = modules.reduce((w, m) => m.dependenciesErrors.forEach(x => w.push(x)), []);
-		this.warnings = modules.reduce((w, m) => m.warnings.forEach(x => w.push(x)), []);
-		this.errors = modules.reduce((w, m) => m.errors.forEach(x => w.push(x)), []);
 		this.moduleArgument = rootModule.moduleArgument;
 		this.exportsArgument = rootModule.exportsArgument;
 		this.strict = true;
-		modules.forEach((m, idx) => {
-			for(const dep of m.dependencies.filter(dep => !modulesSet.has(dep.module))) {
-				this.dependencies.push(dep);
-			}
-		});
+
+		this.dependencies = [];
+		this.dependenciesWarnings = [];
+		this.dependenciesErrors = [];
+		this.warnings = [];
+		this.errors = [];
+		for(const m of modules) {
+			// populate dependencies
+			m.dependencies.filter(dep => !modulesSet.has(dep.module))
+				.forEach(d => this.dependencies.push(d));
+			// populate dep warning
+			m.dependenciesWarnings.forEach(depWarning => this.dependenciesWarnings.push(depWarning));
+			// populate dep errors
+			m.dependenciesErrors.forEach(depError => this.dependenciesErrors.push(depError));
+			// populate warnings
+			m.warnings.forEach(warning => this.warnings.push(warning));
+			// populate errors
+			m.errors.forEach(error => this.errors.push(error));
+		}
 	}
 
 	identifier() {