class Steep::AST::Types::Union

def self.build(types:, location: nil)
  types.flat_map do |type|
    if type.is_a?(Union)
      type.types
    else
      [type]
    end
  end.map do |type|
    case type
    when AST::Types::Any
      return AST::Types::Any.new(location: location)
    when AST::Types::Top
      return AST::Types::Top.new(location: location)
    when AST::Types::Bot
      nil
    else
      type
    end
  end.compact.uniq.yield_self do |tys|
    if tys.length == 1
      tys.first
    else
      new(types: tys.sort_by(&:hash), location: location)
    end
  end
end