diff --git a/lib/absinthe/blueprint/schema/enum_type_definition.ex b/lib/absinthe/blueprint/schema/enum_type_definition.ex
index fa8fe7f882..59951c605f 100644
--- a/lib/absinthe/blueprint/schema/enum_type_definition.ex
+++ b/lib/absinthe/blueprint/schema/enum_type_definition.ex
@@ -30,7 +30,6 @@ defmodule Absinthe.Blueprint.Schema.EnumTypeDefinition do
           errors: [Absinthe.Phase.Error.t()]
         }
 
-  @spec build(t, any) :: Absinthe.Type.Enum.t()
   def build(type_def, _schema) do
     %Absinthe.Type.Enum{
       identifier: type_def.identifier,
diff --git a/lib/absinthe/schema/notation/sdl_render.ex b/lib/absinthe/schema/notation/sdl_render.ex
index 9eda182dfb..e7fb38b700 100644
--- a/lib/absinthe/schema/notation/sdl_render.ex
+++ b/lib/absinthe/schema/notation/sdl_render.ex
@@ -109,7 +109,14 @@ defmodule Absinthe.Schema.Notation.SDL.Render do
           nil
 
         value when is_atom(value) ->
-          definition = Enum.find(type_definitions, fn d -> input_value.type == d.identifier end)
+          typ =
+            case input_value.type do
+              %Absinthe.Blueprint.TypeReference.NonNull{of_type: t} -> t
+              %Absinthe.Blueprint.TypeReference.List{of_type: t} -> t
+              t -> t
+            end
+
+          definition = Enum.find(type_definitions, fn d -> typ == d.identifier end)
 
           case definition do
             nil ->
diff --git a/test/absinthe/schema/sdl_render_test.exs b/test/absinthe/schema/sdl_render_test.exs
index 2eb9db992f..cb4e584ba9 100644
--- a/test/absinthe/schema/sdl_render_test.exs
+++ b/test/absinthe/schema/sdl_render_test.exs
@@ -198,7 +198,7 @@ defmodule Absinthe.Schema.SdlRenderTest do
         arg :times, :integer, default_value: 10, description: "The number of times"
         arg :time_interval, :integer
         arg :time_string, :string, default_value: "2021"
-        arg :order_status, :order_status, default_value: :processing
+        arg :order_status, non_null(:order_status), default_value: :processing
       end
 
       field :search, :search_result
@@ -259,7 +259,7 @@ defmodule Absinthe.Schema.SdlRenderTest do
 
                  timeString: String = "2021"
 
-                 orderStatus: OrderStatus = PROCESSING
+                 orderStatus: OrderStatus! = PROCESSING
                ): String
                search: SearchResult
              }