anchor.diff:    /// Returns a possibly synthesized name for this library, consistent with
     /// the names across all [toString] calls.
     String toString() => debugLibraryName(this);
  +
  +  Location _getLocationInEnclosingFile(int offset) {
  +    return enclosingProgram.getLocation(fileUri, offset);
  +  }
   }
   
   /// The degree to which the contents of a class have been loaded into memory.
  
positive.code:   void replaceSetterInterfaceWith(Procedure setter) {
      _setterInterface.target = setter;
      _setterInterface = new _MemberAccessor(this);
    }
  }
  
  
negative.code:   void remove() {
      parent?.replaceChild(this, null);
      parent = null;
    }
  
    Program get enclosingProgram => parent?.enclosingProgram;
  
    /// Returns the best known source location of the given AST node, or `null` if
    /// the node is orphaned.
    ///
    /// This getter is intended for diagnostics and debugging, and should be
    /// avoided in production code.
    Location get location {
      if (fileOffset == noOffset) return parent?.location;
      return _getLocationInEnclosingFile(fileOffset);
    }
  
    Location _getLocationInEnclosingFile(int offset) {
      return parent?._getLocationInEnclosingFile(offset);
    }
  }
  
  