Don't allow packages to depend on themselves.

sdk/lib/_internal/pub/test/validator/dependency_test.dart

 // Copyright (c) 2013, 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.
 
 import 'dart:async';
 import 'dart:json' as json;
 
 import 'package:http/http.dart' as http;
 import 'package:http/testing.dart';
 import 'package:path/path.dart' as path;
@@ skipping 219 matching lines @@
                   }
                 }
               }
             }))
           ]).create();
 
           expectDependencyValidationWarning('  foo: ">=0.1.2 <0.1.3"');
         });
       });
     });
-
-    integration('has a hosted dependency on itself', () {
-      d.dir(appPath, [
-        d.libPubspec("test_pkg", "1.0.0", deps: {
-          "test_pkg": ">=1.0.0"
-        })
-      ]).create();
-
-      expectValidationWarning(dependency);
-    });
   });
 }