Fix errors and warnings

pkg/analyzer/lib/src/kernel/ast_from_analyzer.dart

Index: pkg/analyzer/lib/src/kernel/ast_from_analyzer.dart
diff --git a/pkg/analyzer/lib/src/kernel/ast_from_analyzer.dart b/pkg/analyzer/lib/src/kernel/ast_from_analyzer.dart
index b5227284f19902b6e84d72ba6ecb516d4bcc51d4..9376d53f5ed1110524168ac50f2116ccb26731ad 100644
--- a/pkg/analyzer/lib/src/kernel/ast_from_analyzer.dart
+++ b/pkg/analyzer/lib/src/kernel/ast_from_analyzer.dart
@@ -2528,7 +2528,7 @@ class ClassBodyBuilder extends GeneralizingAstVisitor<Null> {
         assert(defaultConstructor.enclosingElement == node.element);
         if (!defaultConstructor.isSynthetic) {
           throw 'Non-synthetic default constructor not in list of members. '
-              '${node} $element $defaultConstructor';
+              '$node $element $defaultConstructor';
         }
         var memberNode = scope.getMemberReference(defaultConstructor);
         classNode.addMember(memberNode);