anchor.diff:      checkTypeRef(
           serializeTypeText('C',
               otherDeclarations: 'library my.lib; import "a.dart";'),
  -        'file:///a.dart',
  +        absUri('/a.dart'),
           'a.dart',
           'C');
     }
  
positive.code:     checkTypeRef(
          serializeTypeText('p.C',
              otherDeclarations: 'library my.lib; import "a.dart" as p;'),
          'file:///a.dart',
          'a.dart',
          'C',
          expectedPrefix: 'p');
  
negative.code:     addNamedSource('/a.dart', 'library a; export "b.dart";');
      addNamedSource('/b.dart', 'library b; class C {}');
      checkTypeRef(serializeTypeText('C', otherDeclarations: 'import "a.dart";'),
          absUri('/b.dart'), 'b.dart', 'C');
    }
  
    test_type_reference_to_import_of_export_via_prefix() {
  