anchor.diff:      // element is marked as used and we add its dependencies in the declaration
       // list to traverse. Once this list is empty `usedMembers` contains every
       // declarations reachable from an entry-point.
  -    var toTraverse = Queue.of(usedMembers);
  -    while (toTraverse.isNotEmpty) {
  -      var declaration = toTraverse.removeLast();
  +    var declarationsToCheck = Queue.of(usedMembers);
  +    while (declarationsToCheck.isNotEmpty) {
  +      var declaration = declarationsToCheck.removeLast();
         for (var dep in dependencies[declaration]!) {
           if (usedMembers.add(dep)) {
  -          toTraverse.add(dep);
  +          declarationsToCheck.add(dep);
           }
         }
       }
  
positive.code:       }
      }
  
      // The following map contains for every declaration the set of the
      // declarations it references.
      var dependencies = {
        for (var declaration in topDeclarations)
          declaration: declaration
              .traverseNodesInDFS()
              .expand((e) => [
                    if (e is SimpleIdentifier) e.staticElement,
                    // with `id++` staticElement of `id` is null
                    if (e is CompoundAssignmentExpression) ...[
                      e.readElement,
                      e.writeElement,
                    ],
                  ])
              .whereNotNull()
              .map((e) => e.thisOrAncestorMatching((a) =>
                  a.enclosingElement3 == null ||
                  a.enclosingElement3 is CompilationUnitElement))
              .map((e) => declarationByElement[e])
              .whereNotNull()
              .where((e) => e != declaration)
              .toSet(),
      };
  
      var usedMembers = entryPoints.toSet();
      // The following variable will be used to visit every reachable declaration
  
negative.code: import 'package:analyzer/dart/ast/visitor.dart';
  import 'package:analyzer/dart/element/element.dart';
  import 'package:analyzer/dart/element/type.dart';
  
  import '../analyzer.dart';
  
  const _desc = 'Unreachable top-level members in executable libraries.';
  
  