Type resolve

typer.rb

class Typer
  def resolve
    old_len = @deferred_nodes.length
    while true
      @deferred_nodes.each do |node|
        type = infer(node)
        if type != nil
          @deferred_nodes.remove(node)
        end
      end
    
      if @deferred_nodes.length == 0
        break
      elsif old_len == @deferred_nodes.length
        raise # can't infer error!
      end
    end
  end
end