# File lib/mongoid/relations/bindings/referenced/many.rb, line 19
          def bind_one(doc)
            unless _binding?
              _binding do
                doc.you_must(metadata.foreign_key_setter, base.id)
                if metadata.type
                  doc.you_must(metadata.type_setter, base.class.model_name)
                end
                doc.send(metadata.inverse_setter, base)
              end
            end
          end