anchor.diff:        .toList(growable: false));
   
     @override
  -  sql.SqlNode get as =>
  -      this.isAliased ? sql.as(target, name) : sql.as(this, name);
  +  sql.SqlNode get as => isAliased ? sql.as(target, name) : this;
   
     @override
     sql.SqlNode get unqualified => sql.node(name).single;
  
positive.code:   SqlColumn alias(String alias) {
      SqlColumnImpl column = _cachedColumnAliases[alias];
      if (column == null) {
        column = nodeManager.registerNode(
            new SqlColumnImpl.aliased(alias, this, isPrimaryKey, table));
  
        if (isShared) {
          column = column.share();
  
negative.code:   @override
    SqlColumnImpl createClone(bool freeze) =>
        new SqlColumnImpl.cloneFrom(this, freeze);
  
    SqlColumn createColumnAlias(String alias) =>
        new SqlColumnImpl.aliased(alias, this, isPrimaryKey, table);
  
    @override
    createNode() {
  