A couple of tweaks.

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

Index: pkg/analyzer/lib/src/dart/element/element.dart
diff --git a/pkg/analyzer/lib/src/dart/element/element.dart b/pkg/analyzer/lib/src/dart/element/element.dart
index d6eceaaf55d3e919b93391e20c92f5f26a336b7d..154a8df1af7124e3d9c24827df1658dd886a2ee5 100644
--- a/pkg/analyzer/lib/src/dart/element/element.dart
+++ b/pkg/analyzer/lib/src/dart/element/element.dart
@@ -1913,7 +1913,7 @@ class CompilationUnitElementImpl extends UriReferencedElementImpl
 
   @override
   ClassElement getEnum(String enumName) {
-    for (ClassElement enumDeclaration in _enums) {
+    for (ClassElement enumDeclaration in enums) {
       if (enumDeclaration.name == enumName) {
         return enumDeclaration;
       }