Check for missing elements (issue 26987)

pkg/analyzer/lib/src/generated/error_verifier.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 analyzer.src.generated.error_verifier;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 4375 matching lines @@
             StaticWarningCode.MISSING_ENUM_CONSTANT_IN_SWITCH,
             offset,
             end - offset,
             [constantNames[i]]);
       }
     }
   }
 
   void _checkForMissingJSLibAnnotation(Annotation node) {
     if (node.elementAnnotation?.isJS ?? false) {
-      Element element = ElementLocator.locate(node.parent);
-      if (element?.library?.isJS != true) {
+      if (_currentLibrary.isJS != true) {

[pquitslund, 2016/07/29 20:14:30]

Is `_currentLibrary` certain to be non-null?  Or did you mean
`_currentLibrary?.isJS != true`?

[Brian Wilkerson, 2016/07/29 20:19:37]

Yes. (It's a final field initialized in the constructor and de-referenced in the
constructor, so if `null` were ever passed in the constructor would throw an
exception.)

         _errorReporter.reportErrorForNode(
-            HintCode.MISSING_JS_LIB_ANNOTATION, node, [element.name]);
+            HintCode.MISSING_JS_LIB_ANNOTATION, node);
       }
     }
   }
 
   /**
    * Verify that the given function [body] does not contain return statements
    * that both have and do not have return values.
    *
    * See [StaticWarningCode.MIXED_RETURN_TYPES].
    */
@@ skipping 2045 matching lines @@
 class _InvocationCollector extends RecursiveAstVisitor {
   final List<String> superCalls = <String>[];
 
   @override
   visitMethodInvocation(MethodInvocation node) {
     if (node.target is SuperExpression) {
       superCalls.add(node.methodName.name);
     }
   }
 }