class Steep::TypeInference::LocalVariableTypeEnv::Entry

def +(other)
  self.class.new(type: AST::Types::Union.build(types: [type, other.type]),
                 annotations: annotations + other.annotations,
                 nodes: nodes + other.nodes)
end

def ==(other)
  other.is_a?(Entry) &&
    other.type == type &&
    other.annotations == annotations &&
    other.nodes == nodes
end

def initialize(type:, annotations: [], nodes: [])
  @type = type
  @annotations = Set.new(annotations)
  @nodes = Set[].compare_by_identity.merge(nodes)
end

def optional
  self.class.new(type: AST::Types::Union.build(types: [type, AST::Builtin.nil_type]),
                 annotations: annotations,
                 nodes: nodes)
end

def update(type: self.type, annotations: self.annotations, nodes: self.nodes)
  Entry.new(type: type, annotations: annotations, nodes: nodes)
end