Unscoping a model in an association

post.rb

class Post < ActiveRecord::Base
  has_many :comments
  default_scope { where(public: true) }
end

class Comment < ActiveRecord::Base
  belongs_to :post
  default_scope { where(deleted_at: nil) }
  
  def self.with_deleted
    all.tap { |rel| rel.default_scoped = false }
  end
end

Post.first.comments.with_deleted