@Override public ImmutableMap<String, String> getLoadFlags() { if (loadFlags == null) { Map<String, String> loadFlagsBuilder = new TreeMap<String, String>(); loadFlagsBuilder.putAll(delegate.getLoadFlags()); FeatureSet features = ((JsAst) ast).getFeatures(compiler); if (features.hasEs6Modules()) { if (loadFlagsBuilder.containsKey("module")) { compiler.report(JSError.make(MODULE_CONFLICT, getName())); } loadFlagsBuilder.put("module", "es6"); } String version = features.version(); if (!version.equals("es3")) { loadFlagsBuilder.put("lang", version); } loadFlags = ImmutableMap.copyOf(loadFlagsBuilder); } return loadFlags; }