Reorganize InheritedRefenenceContributor to serve angular completion

pkg/analysis_server/lib/src/services/completion/dart/optype.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library services.completion.dart.optype;
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_target.dart';
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 117 matching lines @@
   /**
    * Indicate whether only type names should be suggested
    */
   bool get includeOnlyNamedArgumentSuggestions =>
       includeNamedArgumentSuggestions &&
       !includeTypeNameSuggestions &&
       !includeReturnValueSuggestions &&
       !includeVoidReturnSuggestions;
 
   /**
+   * Return `true` if free standing identifiers should be suggested
+   */
+  bool get includeIdentifiers {
+    return !isPrefixed &&
+        (includeReturnValueSuggestions ||
+            includeTypeNameSuggestions ||
+            includeVoidReturnSuggestions ||
+            includeConstructorSuggestions);
+  }
+
+  /**
    * Indicate whether only type names should be suggested
    */
   bool get includeOnlyTypeNameSuggestions =>
       includeTypeNameSuggestions &&
       !includeNamedArgumentSuggestions &&
       !includeReturnValueSuggestions &&
       !includeVoidReturnSuggestions;
 }
 
 class _OpTypeAstVisitor extends GeneralizingAstVisitor {
@@ skipping 748 matching lines @@
   }
 
   bool _isEntityPrevTokenSynthetic() {
     Object entity = this.entity;
     if (entity is AstNode && entity.beginToken.previous?.isSynthetic ?? false) {
       return true;
     }
     return false;
   }
 }