diff --git a/pkg/analyzer/lib/src/dart/element/element.dart b/pkg/analyzer/lib/src/dart/element/element.dart
index b331eb3..20bdd9a 100644
--- a/pkg/analyzer/lib/src/dart/element/element.dart
+++ b/pkg/analyzer/lib/src/dart/element/element.dart
@@ -7344,6 +7344,7 @@
         constraints = onClause.superclassConstraints
             .map((node) => node.type)
             .whereType<InterfaceType>()
+            .where(_isInterfaceTypeInterface)
             .toList();
       }
       if (constraints == null || constraints.isEmpty) {