diff --git a/lib/administrate/field/base.rb b/lib/administrate/field/base.rb
index fcc67c8d5e..dbc73a39b1 100644
--- a/lib/administrate/field/base.rb
+++ b/lib/administrate/field/base.rb
@@ -20,6 +20,10 @@ def self.field_type
         to_s.split("::").last.underscore
       end
 
+      def self.permitted_attribute(attr, _options = nil)
+        attr
+      end
+
       def initialize(attribute, data, page, options = {})
         @attribute = attribute
         @data = data
@@ -28,10 +32,6 @@ def initialize(attribute, data, page, options = {})
         @options = options
       end
 
-      def self.permitted_attribute(attr, _options = nil)
-        attr
-      end
-
       def html_class
         self.class.html_class
       end
diff --git a/lib/administrate/field/has_one.rb b/lib/administrate/field/has_one.rb
index 32cbe60ff1..c8d59186ee 100644
--- a/lib/administrate/field/has_one.rb
+++ b/lib/administrate/field/has_one.rb
@@ -3,13 +3,6 @@
 module Administrate
   module Field
     class HasOne < Associative
-      def nested_form
-        @nested_form ||= Administrate::Page::Form.new(
-          resolver.dashboard_class.new,
-          data || resolver.resource_class.new,
-        )
-      end
-
       def self.permitted_attribute(attr, options = nil)
         associated_class_name =
           if options
@@ -24,6 +17,13 @@ def self.permitted_attribute(attr, options = nil)
         { "#{attr}_attributes": related_dashboard_attributes }
       end
 
+      def nested_form
+        @nested_form ||= Administrate::Page::Form.new(
+          resolver.dashboard_class.new,
+          data || resolver.resource_class.new,
+        )
+      end
+
       private
 
       def resolver
diff --git a/lib/administrate/field/polymorphic.rb b/lib/administrate/field/polymorphic.rb
index 22294b5e95..e622542512 100644
--- a/lib/administrate/field/polymorphic.rb
+++ b/lib/administrate/field/polymorphic.rb
@@ -3,6 +3,10 @@
 module Administrate
   module Field
     class Polymorphic < BelongsTo
+      def self.permitted_attribute(attr, _options = nil)
+        { attr => %i{type value} }
+      end
+
       def associated_resource_grouped_options
         classes.map do |klass|
           [klass.to_s, candidate_resources_for(klass).map do |resource|
@@ -11,10 +15,6 @@ def associated_resource_grouped_options
         end
       end
 
-      def self.permitted_attribute(attr, _options = nil)
-        { attr => %i{type value} }
-      end
-
       def permitted_attribute
         { attribute => %i{type value} }
       end