anchor.diff:          case 2:
             // returning from await.
             // implicit return
  -          return thenHelper(null, 0, __completer, null);
  +          return thenHelper(null, 0, __completer);
           case 1:
             // rethrow
             return thenHelper(__currentError, 1, __completer);
         }
     });
  -  return thenHelper(null, body, __completer, null);
  +  return thenHelper(null, body, __completer);
   }""");
   
     testAsyncTransform("""
  
positive.code:           // after finally
            print(exception);
            // implicit return
            return thenHelper(null, 0, __completer, null);
          case 1:
            // rethrow
            return thenHelper(__currentError, 1, __completer);
        }
    });
    return thenHelper(null, body, __completer, null);
  }""");
  
    testSyncStarTransform("""
  
negative.code:         case 5:
            // after finally
            // implicit return
            return thenHelper(null, 0, __completer);
          case 1:
            // rethrow
            return thenHelper(__currentError, 1, __completer);
        }
    });
    return thenHelper(null, body, __completer);
  }""");
  
    testAsyncTransform("""
  