cleanup (#1819)

diff --git a/analysis_options.yaml b/analysis_options.yaml
index d170519..80c85b2 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -7,6 +7,7 @@
     # ignore vscode .history files
     - .history/**
     - test/_data/**
+    - test/mock_packages/**
     - test/rules/**
 linter:
   rules:
diff --git a/lib/src/ast.dart b/lib/src/ast.dart
index 7c5c5b1..f84dde5 100644
--- a/lib/src/ast.dart
+++ b/lib/src/ast.dart
@@ -10,9 +10,9 @@
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
 import 'package:analyzer/file_system/file_system.dart';
-import 'package:analyzer/src/error/codes.dart';
-import 'package:analyzer/src/generated/resolver.dart';
-import 'package:analyzer/src/workspace/workspace.dart';
+import 'package:analyzer/src/error/codes.dart'; // ignore: implementation_imports
+import 'package:analyzer/src/generated/resolver.dart'; // ignore: implementation_imports
+import 'package:analyzer/src/workspace/workspace.dart'; // ignore: implementation_imports
 import 'package:path/path.dart' as path;
 
 import 'analyzer.dart';