Reform and Form Helper workaround

reform_simple_form.rb

# concepts/thing/contract/contract.rb

require 'disposable/twin/property/hash'

module Thing::Contract
  class Contract < Reform::Form
    include Disposable::Twin::Property::Hash

    property :data, field: :hash do
      property :foo_bar
    end
  end
end

# views/things/_form.html.erb
# <%= f.simple_fields_for :data do %>
#  <%= f.input :foo_bar %>
# <% end %>
# f.simple_fields_for will raise error, method `persisted?` not found for Hash:{}

## Work around
# concepts/thing/contract/contract.rb

require 'disposable/twin/property/hash'

module Thing::Contract
  class Contract < Reform::Form
    include Disposable::Twin::Property::Hash

    property :data, field: :hash do
      # Add this
      def persisted?
        false
      end
      property :foo_bar
    end
  end
end