diff --git a/lib/src/importer/legacy_node.dart b/lib/src/importer/legacy_node.dart
index 83528fc26..d122fc8a7 100644
--- a/lib/src/importer/legacy_node.dart
+++ b/lib/src/importer/legacy_node.dart
@@ -2,4 +2,5 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
-export 'legacy_node/interface.dart' if (dart.library.js) 'legacy_node/implementation.dart';
+export 'legacy_node/interface.dart'
+    if (dart.library.js) 'legacy_node/implementation.dart';
diff --git a/lib/src/parse/stylesheet.dart b/lib/src/parse/stylesheet.dart
index afe741594..5685f151c 100644
--- a/lib/src/parse/stylesheet.dart
+++ b/lib/src/parse/stylesheet.dart
@@ -1398,7 +1398,11 @@ abstract class StylesheetParser extends Parser {
     try {
       return Parser.parseIdentifier(namespace, logger: logger);
     } on SassFormatException {
-      error('Invalid Sass identifier "$namespace"', scanner.spanFrom(start));
+      error(
+          'The default namespace "$namespace" is not a valid Sass identifier.\n'
+          "\n"
+          'Recommendation: add an "as" clause to define an explicit namespace.',
+          scanner.spanFrom(start));
     }
   }