SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 2)
    Function CAST (alias t) (children 1)
     ExpressionList (children 2)
      Literal \'[(1, \\\'a\\\'), (3, \\\'b\\\')]\'
      Literal \'Nested(u UInt8, s String)\'
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Identifier t
