Use of projection dsl is not available in Relation#exclude

[Armin]

Describe the bug

It I try to use the projection dsl in combination with #exlude...

mentions
  .select { integer::count(issue_id).as(:unit_mention_count) }
  .where(unit_id: 3, read: false)
  .exclude { user_ids.any(1) }

...I get the following error:

NoMethodError:
  undefined method `any' for #<Sequel::SQL::Identifier @value=>:user_ids>
         .exclude { user_ids.any(1) }

Expected behavior

SELECT COUNT(\"mentions\".\"issue_id\") AS \"unit_mention_count\" FROM \"mentions\" WHERE ((\"unit_id\" = 3) AND (\"read\" IS FALSE) AND NOT (1 = ANY(\"mentions\".\"user_ids\")))

Workaround

Overwrite #exclude at relation

class Mentions < ROM::Relation[:sql]
  schema(:mentions, infer: true) do
  end

  def exclude(*args, &block)
    if block
      exclude(*args).exclude(schema.canonical.restriction(&block))
    elsif args.size == 1 && args[0].is_a?(Hash)
      new(dataset.exclude(coerce_conditions(args[0])))
    elsif !args.empty?
      new(dataset.exclude(*args))
    else
      self
    end
  end
end

WDYT? I could provide a PR.