anchor.diff:      final source = newSource('/test.dart', code);
       await getDirectives(source);
       final component = directives.first as Component;
  -    expect(component.exports, const isInstanceOf<ListLiteral>());
  +    expect(component.exports, isA<ListLiteral>());
       final exports = (component.exports as ListLiteral).items;
       expect(exports, hasLength(2));
       {
  
positive.code:     expect(pipes, hasLength(2));
      {
        final pipe = pipes[0];
        expect(pipe, const isInstanceOf<Pipe>());
        expect(pipe.pipeName, 'pipeA');
      }
      {
        final pipe = pipes[1];
        expect(pipe, const isInstanceOf<Pipe>());
        expect(pipe.pipeName, 'pipeB');
      }
      errorListener.assertNoErrors();
  
negative.code:     expect(directives, hasLength(2));
      {
        final directive = directives[0];
        expect(directive, isA<Directive>());
        {
          final selector = directive.selector;
          expect(selector, isA<ElementNameSelector>());
          expect(selector.toString(), 'dir-a');
        }
      }
      {
        final directive = directives[1];
        expect(directive, isA<Directive>());
        {
          final selector = directive.selector;
          expect(selector, isA<ElementNameSelector>());
          expect(selector.toString(), 'dir-b');
        }
      }
  