Handle default formal parameters in LocalElementBuilder

pkg/analyzer/lib/src/dart/element/builder.dart

Index: pkg/analyzer/lib/src/dart/element/builder.dart
diff --git a/pkg/analyzer/lib/src/dart/element/builder.dart b/pkg/analyzer/lib/src/dart/element/builder.dart
index e34448485322ba5aa48e7b4612182341d300e5e6..b45f44e9742c3ba070731d3f5e7730edd0e82d8e 100644
--- a/pkg/analyzer/lib/src/dart/element/builder.dart
+++ b/pkg/analyzer/lib/src/dart/element/builder.dart
@@ -1125,6 +1125,14 @@ class LocalElementBuilder extends _BaseElementBuilder {
   }
 
   @override
+  Object visitDefaultFormalParameter(DefaultFormalParameter node) {
+    super.visitDefaultFormalParameter(node);
+    buildParameterInitializer(
+        node.element as ParameterElementImpl, node.defaultValue);
+    return null;
+  }
+
+  @override
   Object visitFunctionDeclaration(FunctionDeclaration node) {
     FunctionExpression expression = node.functionExpression;
     if (expression == null) {