class RBS::Types::Union

def ==(other)
  other.is_a?(Union) && other.types == types
end

def each_type(&block)
  if block
    types.each(&block)
  else
    enum_for :each_type
  end
end

def free_variables(set = Set.new)
  set.tap do
    types.each do |type|
      type.free_variables set
    end
  end
end

def hash
  self.class.hash ^ types.hash
end

def initialize(types:, location:)
  @types = types
  @location = location
end

def map_type(&block)
  if block
    Union.new(types: types.map(&block), location: location)
  else
    enum_for :map_type
  end
end

def map_type_name(&block)
  Union.new(
    types: types.map {|type| type.map_type_name(&block) },
    location: location
  )
end

def sub(s)
  self.class.new(types: types.map {|ty| ty.sub(s) },
                 location: location)
end

def to_json(state = _ = nil)
  { class: :union, types: types, location: location }.to_json(state)
end

def to_s(level = 0)
  if level > 0
    "(#{types.join(" | ")})"
  else
    types.join(" | ")
  end
end