class Steep::AST::Types::Instance

def self.instance
  @instance ||= new()
end

def ==(other)
  other.is_a?(Instance)
end

def free_variables
  @@fvs
end

def hash
  self.class.hash
end

def initialize(location: nil)
  @location = location
end

def level
  [0]
end

def subst(s)
  if s.instance_type
    s.instance_type
  else
    self
  end
end

def to_s
  "instance"
end

def with_location(new_location)
  self.class.new(location: new_location)
end