SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function map (alias map) (children 1)
     ExpressionList (children 4)
      Literal UInt64_1
      Literal \'val1\'
      Literal UInt64_2
      Literal \'val2\'
   ExpressionList (children 2)
    Function CAST (alias c) (children 1)
     ExpressionList (children 2)
      Identifier map
      Literal \'Array(Tuple(k UInt32, v String))\'
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Identifier c
