Check for missing elements (issue 26987)

pkg/analyzer/lib/src/generated/error_verifier.dart

Index: pkg/analyzer/lib/src/generated/error_verifier.dart
diff --git a/pkg/analyzer/lib/src/generated/error_verifier.dart b/pkg/analyzer/lib/src/generated/error_verifier.dart
index 0a54caa945d7caa6d04eff3b93240b1e30095c02..d7b7867704c348d562e63119d418950c41da4632 100644
--- a/pkg/analyzer/lib/src/generated/error_verifier.dart
+++ b/pkg/analyzer/lib/src/generated/error_verifier.dart
@@ -4393,10 +4393,9 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
 
   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);
       }
     }
   }