scaffold nested name controller should be fine.

railties/lib/rails/generators/erb/scaffold/templates/_form.html.erb

-<%%= form_with(model: <%= singular_table_name %>, local: true) do |form| %>
+<%%= form_with(model: <%= model_resource_name %>, local: true) do |form| %>
   <%% if <%= singular_table_name %>.errors.any? %>
     <div id="error_explanation">
       <h2><%%= pluralize(<%= singular_table_name %>.errors.count, "error") %> prohibited this <%= singular_table_name %> from being saved:</h2>

railties/lib/rails/generators/erb/scaffold/templates/index.html.erb

@@ -18,9 +18,9 @@
 <% attributes.reject(&:password_digest?).each do |attribute| -%>
         <td><%%= <%= singular_table_name %>.<%= attribute.name %> %></td>
 <% end -%>
-        <td><%%= link_to 'Show', <%= singular_table_name %> %></td>
-        <td><%%= link_to 'Edit', edit_<%= singular_table_name %>_path(<%= singular_table_name %>) %></td>
-        <td><%%= link_to 'Destroy', <%= singular_table_name %>, method: :delete, data: { confirm: 'Are you sure?' } %></td>
+        <td><%%= link_to 'Show', <%= model_resource_name %> %></td>
+        <td><%%= link_to 'Edit', edit_<%= singular_route_name %>_path(<%= singular_table_name %>) %></td>
+        <td><%%= link_to 'Destroy', <%= model_resource_name %>, method: :delete, data: { confirm: 'Are you sure?' } %></td>
       </tr>
     <%% end %>
   </tbody>
@@ -28,4 +28,4 @@
 
 <br>
 
-<%%= link_to 'New <%= singular_table_name.titleize %>', new_<%= singular_table_name %>_path %>
+<%%= link_to 'New <%= singular_table_name.titleize %>', new_<%= singular_route_name %>_path %>

railties/lib/rails/generators/named_base.rb

@@ -100,11 +100,11 @@ def uncountable? # :doc:
         end
 
         def index_helper # :doc:
-          uncountable? ? "#{plural_table_name}_index" : plural_table_name
+          uncountable? ? "#{plural_route_name}_index" : plural_route_name
         end
 
         def show_helper # :doc:
-          "#{singular_table_name}_url(@#{singular_table_name})"
+          "#{singular_route_name}_url(@#{singular_table_name})"
         end
 
         def edit_helper # :doc:
@@ -112,7 +112,7 @@ def edit_helper # :doc:
         end
 
         def new_helper # :doc:
-          "new_#{singular_table_name}_url"
+          "new_#{singular_route_name}_url"
         end
 
         def field_id(attribute_name)
@@ -152,6 +152,35 @@ def application_name # :doc:
           end
         end
 
+        def redirect_resource_name # :doc:
+          model_resource_name(prefix: "@")
+        end
+
+        def model_resource_name(prefix: "") # :doc:
+          resource_name = "#{prefix}#{singular_table_name}"
+          if controller_class_path.empty?
+            resource_name
+          else
+            "[#{controller_class_path.map { |name| ":" + name }.join(", ")}, #{resource_name}]"
+          end
+        end
+
+        def singular_route_name # :doc:
+          if controller_class_path.empty?
+            singular_table_name
+          else
+            "#{controller_class_path.join('_')}_#{singular_table_name}"
+          end
+        end
+
+        def plural_route_name # :doc:
+          if controller_class_path.empty?
+            plural_table_name
+          else
+            "#{controller_class_path.join('_')}_#{plural_table_name}"
+          end
+        end
+
         def assign_names!(name)
           @class_path = name.include?("/") ? name.split("/") : name.split("::")
           @class_path.map!(&:underscore)

railties/lib/rails/generators/rails/scaffold_controller/templates/controller.rb

@@ -29,7 +29,7 @@ def create
     @<%= singular_table_name %> = <%= orm_class.build(class_name, "#{singular_table_name}_params") %>
 
     if @<%= orm_instance.save %>
-      redirect_to @<%= singular_table_name %>, notice: <%= "'#{human_name} was successfully created.'" %>
+      redirect_to <%= redirect_resource_name %>, notice: <%= "'#{human_name} was successfully created.'" %>
     else
       render :new
     end
@@ -38,7 +38,7 @@ def create
   # PATCH/PUT <%= route_url %>/1
   def update
     if @<%= orm_instance.update("#{singular_table_name}_params") %>
-      redirect_to @<%= singular_table_name %>, notice: <%= "'#{human_name} was successfully updated.'" %>
+      redirect_to <%= redirect_resource_name %>, notice: <%= "'#{human_name} was successfully updated.'" %>
     else
       render :edit
     end

railties/test/generators/named_base_test.rb

@@ -131,6 +131,19 @@ def test_scaffold_plural_names_with_model_name_option
     assert_name g, "admin/foos",  :controller_file_path
     assert_name g, "foos",        :controller_file_name
     assert_name g, "admin.foos",  :controller_i18n_scope
+    assert_name g, "admin_user",  :singular_route_name
+    assert_name g, "admin_users", :plural_route_name
+    assert_name g, "[:admin, @user]", :redirect_resource_name
+    assert_name g, "[:admin, user]",  :model_resource_name
+    assert_name g, "admin_users", :index_helper
+  end
+
+  def test_scaffold_plural_names
+    g = generator ["User"]
+    assert_name g, "@user", :redirect_resource_name
+    assert_name g, "user",  :model_resource_name
+    assert_name g, "user",  :singular_route_name
+    assert_name g, "users", :plural_route_name
   end
 
   private

railties/test/generators/scaffold_controller_generator_test.rb

@@ -174,6 +174,29 @@ def test_model_name_option
       assert_instance_method :index, content do |m|
         assert_match("@users = User.all", m)
       end
+
+      assert_instance_method :create, content do |m|
+        assert_match("redirect_to [:admin, @user]", m)
+      end
+
+      assert_instance_method :update, content do |m|
+        assert_match("redirect_to [:admin, @user]", m)
+      end
+    end
+
+    assert_file "app/views/admin/users/index.html.erb" do |content|
+      assert_match("'Show', [:admin, user]", content)
+      assert_match("'Edit', edit_admin_user_path(user)", content)
+      assert_match("'Destroy', [:admin, user]", content)
+      assert_match("'New User', new_admin_user_path", content)
+    end
+
+    assert_file "app/views/admin/users/new.html.erb" do |content|
+      assert_match("'Back', admin_users_path", content)
+    end
+
+    assert_file "app/views/admin/users/_form.html.erb" do |content|
+      assert_match("model: [:admin, user]", content)
     end
   end