diff --git a/lib/absinthe/blueprint/schema/interface_type_definition.ex b/lib/absinthe/blueprint/schema/interface_type_definition.ex
index b1fd11be9e..26dfbcd048 100644
--- a/lib/absinthe/blueprint/schema/interface_type_definition.ex
+++ b/lib/absinthe/blueprint/schema/interface_type_definition.ex
@@ -45,13 +45,15 @@ defmodule Absinthe.Blueprint.Schema.InterfaceTypeDefinition do
       identifier: type_def.identifier,
       resolve_type: type_def.resolve_type,
       definition: type_def.module,
-      interfaces: type_def.interfaces
+      interfaces: Enum.map(type_def.interfaces, &Blueprint.TypeReference.to_type(&1, schema))
     }
   end
 
   def find_implementors(iface, type_defs) do
+    type_ref = %Blueprint.TypeReference.Identifier{id: iface.identifier}
+
     for %Schema.ObjectTypeDefinition{} = obj <- type_defs,
-        iface.identifier in obj.interfaces,
+        type_ref in obj.interfaces,
         do: obj.identifier
   end
 
diff --git a/lib/absinthe/blueprint/schema/object_type_definition.ex b/lib/absinthe/blueprint/schema/object_type_definition.ex
index 8e7bb9d7bd..cec8837496 100644
--- a/lib/absinthe/blueprint/schema/object_type_definition.ex
+++ b/lib/absinthe/blueprint/schema/object_type_definition.ex
@@ -47,7 +47,7 @@ defmodule Absinthe.Blueprint.Schema.ObjectTypeDefinition do
       name: type_def.name,
       description: type_def.description,
       fields: build_fields(type_def, schema),
-      interfaces: type_def.interfaces,
+      interfaces: Enum.map(type_def.interfaces, &Blueprint.TypeReference.to_type(&1, schema)),
       definition: type_def.module,
       is_type_of: type_def.is_type_of,
       __private__: type_def.__private__
diff --git a/lib/absinthe/blueprint/type_reference.ex b/lib/absinthe/blueprint/type_reference.ex
index a60d7a22a0..7c7ff81993 100644
--- a/lib/absinthe/blueprint/type_reference.ex
+++ b/lib/absinthe/blueprint/type_reference.ex
@@ -45,6 +45,10 @@ defmodule Absinthe.Blueprint.TypeReference do
     name
   end
 
+  def name(%__MODULE__.Identifier{id: id}) do
+    name(id)
+  end
+
   def name(name) do
     name |> to_string() |> String.capitalize()
   end
diff --git a/lib/absinthe/language/interface_type_definition.ex b/lib/absinthe/language/interface_type_definition.ex
index 444808963d..8e6a895a84 100644
--- a/lib/absinthe/language/interface_type_definition.ex
+++ b/lib/absinthe/language/interface_type_definition.ex
@@ -36,7 +36,10 @@ defmodule Absinthe.Language.InterfaceTypeDefinition do
     defp interfaces(interfaces, doc) do
       interfaces
       |> Absinthe.Blueprint.Draft.convert(doc)
-      |> Enum.map(&(&1.name |> Macro.underscore() |> String.to_atom()))
+      |> Enum.map(fn interface ->
+        id = interface.name |> Macro.underscore() |> String.to_atom()
+        %Absinthe.Blueprint.TypeReference.Identifier{id: id}
+      end)
     end
 
     defp source_location(%{loc: nil}), do: nil
diff --git a/lib/absinthe/language/object_type_definition.ex b/lib/absinthe/language/object_type_definition.ex
index 4ca8d55603..77011219fe 100644
--- a/lib/absinthe/language/object_type_definition.ex
+++ b/lib/absinthe/language/object_type_definition.ex
@@ -39,7 +39,10 @@ defmodule Absinthe.Language.ObjectTypeDefinition do
     defp interfaces(interfaces, doc) do
       interfaces
       |> Absinthe.Blueprint.Draft.convert(doc)
-      |> Enum.map(&(&1.name |> Macro.underscore() |> String.to_atom()))
+      |> Enum.map(fn interface ->
+        id = interface.name |> Macro.underscore() |> String.to_atom()
+        %Absinthe.Blueprint.TypeReference.Identifier{id: id}
+      end)
     end
   end
 end
diff --git a/lib/absinthe/phase/schema/introspection.ex b/lib/absinthe/phase/schema/introspection.ex
index b0e8081e7a..3c831f3fb2 100644
--- a/lib/absinthe/phase/schema/introspection.ex
+++ b/lib/absinthe/phase/schema/introspection.ex
@@ -63,7 +63,7 @@ defmodule Absinthe.Phase.Schema.Introspection do
       name: "__typename",
       identifier: :__typename,
       module: __MODULE__,
-      type: :string,
+      type: %Absinthe.Blueprint.TypeReference.Identifier{id: :string},
       description: "The name of the object type currently being queried.",
       complexity: 0,
       triggers: %{},
@@ -80,7 +80,7 @@ defmodule Absinthe.Phase.Schema.Introspection do
       __reference__: Absinthe.Schema.Notation.build_reference(__ENV__),
       name: "__type",
       identifier: :__type,
-      type: :__type,
+      type: %Absinthe.Blueprint.TypeReference.Identifier{id: :__type},
       module: __MODULE__,
       description: "Represents scalars, interfaces, object types, unions, enums in the system",
       triggers: %{},
@@ -105,7 +105,7 @@ defmodule Absinthe.Phase.Schema.Introspection do
     %FieldDefinition{
       name: "__schema",
       identifier: :__schema,
-      type: :__schema,
+      type: %Absinthe.Blueprint.TypeReference.Identifier{id: :__schema},
       module: __MODULE__,
       description: "Represents the schema",
       triggers: %{},
diff --git a/lib/absinthe/phase/schema/validation/interfaces_must_resolve_types.ex b/lib/absinthe/phase/schema/validation/interfaces_must_resolve_types.ex
index 5c774dce44..263232214f 100644
--- a/lib/absinthe/phase/schema/validation/interfaces_must_resolve_types.ex
+++ b/lib/absinthe/phase/schema/validation/interfaces_must_resolve_types.ex
@@ -14,7 +14,7 @@ defmodule Absinthe.Phase.Schema.Validation.InterfacesMustResolveTypes do
       schema.type_definitions
       |> Enum.filter(&match?(%Blueprint.Schema.ObjectTypeDefinition{}, &1))
       |> Enum.flat_map(fn obj ->
-        for iface <- obj.interfaces do
+        for %{id: iface} <- obj.interfaces do
           {iface, obj}
         end
       end)
diff --git a/lib/absinthe/phase/schema/validation/no_interface_cycles.ex b/lib/absinthe/phase/schema/validation/no_interface_cycles.ex
index ec361e4edd..e658c904fa 100644
--- a/lib/absinthe/phase/schema/validation/no_interface_cycles.ex
+++ b/lib/absinthe/phase/schema/validation/no_interface_cycles.ex
@@ -42,7 +42,7 @@ defmodule Absinthe.Phase.Schema.Validation.NoInterfaceCyles do
   defp vertex(%Schema.InterfaceTypeDefinition{} = implementor, graph) do
     :digraph.add_vertex(graph, implementor.identifier)
 
-    for interface <- implementor.interfaces do
+    for interface <- Enum.map(implementor.interfaces, & &1.id) do
       edge(implementor, interface, graph)
     end
 
diff --git a/lib/absinthe/phase/schema/validation/object_interfaces_must_be_valid.ex b/lib/absinthe/phase/schema/validation/object_interfaces_must_be_valid.ex
index 8aca52041f..a9d13ad67a 100644
--- a/lib/absinthe/phase/schema/validation/object_interfaces_must_be_valid.ex
+++ b/lib/absinthe/phase/schema/validation/object_interfaces_must_be_valid.ex
@@ -44,13 +44,14 @@ defmodule Absinthe.Phase.Schema.Validation.ObjectInterfacesMustBeValid do
          implemented_by,
          visited
        ) do
-    current_interface = all_interfaces[object_interface]
+    current_interface = all_interfaces[object_interface.id]
 
-    if current_interface && current_interface.identifier in object.interfaces do
+    if current_interface &&
+         %Blueprint.TypeReference.Identifier{id: current_interface.identifier} in object.interfaces do
       case current_interface do
         %{interfaces: interfaces} = interface ->
           # to prevent walking in cycles we need to filter out visited interfaces
-          interfaces = Enum.filter(interfaces, &(&1 not in visited))
+          interfaces = interfaces |> Enum.filter(&(&1 not in visited))
 
           check_transitive_interfaces(object, tail ++ interfaces, all_interfaces, interface, [
             object_interface | visited
@@ -64,7 +65,7 @@ defmodule Absinthe.Phase.Schema.Validation.ObjectInterfacesMustBeValid do
     else
       detail = %{
         object: object.identifier,
-        interface: object_interface,
+        interface: object_interface.id,
         implemented_by: implemented_by
       }
 
@@ -93,7 +94,7 @@ defmodule Absinthe.Phase.Schema.Validation.ObjectInterfacesMustBeValid do
 
   def explanation(%{object: obj, interface: interface, implemented_by: nil}) do
     """
-    Type "#{obj}" must implement interface type "#{interface}"
+    Type "#{obj}" must implement interface type "#{inspect(interface)}"
 
     #{@description}
     """
diff --git a/lib/absinthe/phase/schema/validation/object_must_implement_interfaces.ex b/lib/absinthe/phase/schema/validation/object_must_implement_interfaces.ex
index d25fff0b27..185dc5887a 100644
--- a/lib/absinthe/phase/schema/validation/object_must_implement_interfaces.ex
+++ b/lib/absinthe/phase/schema/validation/object_must_implement_interfaces.ex
@@ -36,7 +36,7 @@ defmodule Absinthe.Phase.Schema.Validation.ObjectMustImplementInterfaces do
   end
 
   defp validate_objects(%struct{} = object, ifaces, types) when struct in @interface_types do
-    Enum.reduce(object.interfaces, object, fn ident, object ->
+    Enum.reduce(object.interfaces, object, fn %{id: ident}, object ->
       case Map.fetch(ifaces, ident) do
         {:ok, iface} -> validate_object(object, iface, types)
         _ -> object
@@ -162,6 +162,7 @@ defmodule Absinthe.Phase.Schema.Validation.ObjectMustImplementInterfaces do
          types
        ) do
     %{interfaces: field_type_interfaces} = Map.get(types, field_type)
+    field_type_interfaces = Enum.map(field_type_interfaces, & &1.id)
     (interface_ident in field_type_interfaces && :ok) || {:error, field_ident}
   end
 
@@ -196,6 +197,15 @@ defmodule Absinthe.Phase.Schema.Validation.ObjectMustImplementInterfaces do
     :ok
   end
 
+  defp check_covariant(
+         %Blueprint.TypeReference.Identifier{id: id},
+         %Blueprint.TypeReference.Identifier{id: id},
+         _field_ident,
+         _types
+       ) do
+    :ok
+  end
+
   defp check_covariant(
          %Blueprint.TypeReference.Name{name: iface_name},
          %Blueprint.TypeReference.Name{name: type_name},
@@ -208,6 +218,15 @@ defmodule Absinthe.Phase.Schema.Validation.ObjectMustImplementInterfaces do
     check_covariant(itype, type, field_ident, types)
   end
 
+  defp check_covariant(
+         %Blueprint.TypeReference.Identifier{id: iface_identifier},
+         %Blueprint.TypeReference.Identifier{id: type_identifier},
+         field_ident,
+         types
+       ) do
+    check_covariant(iface_identifier, type_identifier, field_ident, types)
+  end
+
   defp check_covariant(nil, _, field_ident, _), do: {:error, field_ident}
   defp check_covariant(_, nil, field_ident, _), do: {:error, field_ident}
 
diff --git a/lib/absinthe/phase/schema/validation/type_references_exist.ex b/lib/absinthe/phase/schema/validation/type_references_exist.ex
index badac8900c..49792b4d12 100644
--- a/lib/absinthe/phase/schema/validation/type_references_exist.ex
+++ b/lib/absinthe/phase/schema/validation/type_references_exist.ex
@@ -131,6 +131,10 @@ defmodule Absinthe.Phase.Schema.Validation.TypeReferencesExist do
     name
   end
 
+  defp inner_type(%Absinthe.Blueprint.TypeReference.Identifier{id: id}) do
+    id
+  end
+
   defp unwrapped?(value) when is_binary(value) or is_atom(value), do: {:ok, value}
   defp unwrapped?(%Absinthe.Blueprint.TypeReference.Name{name: name}), do: {:ok, name}
   defp unwrapped?(%Absinthe.Blueprint.TypeReference.Identifier{id: id}), do: {:ok, id}
diff --git a/lib/absinthe/schema/notation.ex b/lib/absinthe/schema/notation.ex
index 56bc5b9d54..18bc58acba 100644
--- a/lib/absinthe/schema/notation.ex
+++ b/lib/absinthe/schema/notation.ex
@@ -502,12 +502,25 @@ defmodule Absinthe.Schema.Notation do
       |> Keyword.delete(:directives)
       |> Keyword.delete(:args)
       |> Keyword.delete(:meta)
+      |> Keyword.update(:type, nil, &wrap_type/1)
       |> Keyword.update(:description, nil, &wrap_in_unquote/1)
       |> Keyword.update(:default_value, nil, &wrap_in_unquote/1)
 
     {attrs, block}
   end
 
+  defp wrap_type(type) when is_atom(type) do
+    %Absinthe.Blueprint.TypeReference.Identifier{id: type}
+  end
+
+  defp wrap_type(%{of_type: type} = type_reference) do
+    %{type_reference | of_type: wrap_type(type)}
+  end
+
+  defp wrap_type(%Absinthe.Blueprint.TypeReference.Identifier{} = type) do
+    type
+  end
+
   # FIELDS
   @placement {:field, [under: [:input_object, :interface, :object, :schema_declaration]]}
   @doc """
@@ -748,7 +761,7 @@ defmodule Absinthe.Schema.Notation do
   ```
   """
   defmacro arg(identifier, type, attrs) do
-    {attrs, block} = handle_arg_attrs(identifier, type, attrs)
+    {attrs, block} = handle_arg_attrs(identifier, Keyword.put(attrs, :type, type), __CALLER__)
 
     __CALLER__
     |> recordable!(:arg, @placement[:arg])
@@ -761,7 +774,7 @@ defmodule Absinthe.Schema.Notation do
   See `arg/3`
   """
   defmacro arg(identifier, attrs) when is_list(attrs) do
-    {attrs, block} = handle_arg_attrs(identifier, nil, attrs)
+    {attrs, block} = handle_arg_attrs(identifier, attrs, __CALLER__)
 
     __CALLER__
     |> recordable!(:arg, @placement[:arg])
@@ -769,7 +782,7 @@ defmodule Absinthe.Schema.Notation do
   end
 
   defmacro arg(identifier, type) do
-    {attrs, block} = handle_arg_attrs(identifier, type, [])
+    {attrs, block} = handle_arg_attrs(identifier, [type: type], __CALLER__)
 
     __CALLER__
     |> recordable!(:arg, @placement[:arg])
@@ -1318,7 +1331,8 @@ defmodule Absinthe.Schema.Notation do
   end
 
   defmacro non_null(type) do
-    %Absinthe.Blueprint.TypeReference.NonNull{of_type: expand_ast(type, __CALLER__)}
+    type = type |> expand_ast(__CALLER__) |> build_identifier()
+    %Absinthe.Blueprint.TypeReference.NonNull{of_type: type}
   end
 
   @doc """
@@ -1327,7 +1341,8 @@ defmodule Absinthe.Schema.Notation do
   See `field/3` for examples
   """
   defmacro list_of(type) do
-    %Absinthe.Blueprint.TypeReference.List{of_type: expand_ast(type, __CALLER__)}
+    type = type |> expand_ast(__CALLER__) |> build_identifier()
+    %Absinthe.Blueprint.TypeReference.List{of_type: type}
   end
 
   @placement {:import_fields, [under: [:input_object, :interface, :object]]}
@@ -1561,15 +1576,16 @@ defmodule Absinthe.Schema.Notation do
   defp reason(msg) when is_binary(msg), do: [reason: msg]
   defp reason(msg), do: raise(ArgumentError, "Invalid reason: #{msg}")
 
-  def handle_arg_attrs(identifier, type, raw_attrs) do
+  def handle_arg_attrs(identifier, raw_attrs, caller) do
     block = block_from_directive_attrs(raw_attrs)
 
     attrs =
       raw_attrs
+      |> expand_ast(caller)
       |> Keyword.put_new(:name, to_string(identifier))
-      |> Keyword.put_new(:type, type)
       |> Keyword.delete(:directives)
       |> Keyword.delete(:deprecate)
+      |> Keyword.update(:type, nil, &wrap_type/1)
       |> Keyword.update(:description, nil, &wrap_in_unquote/1)
       |> Keyword.update(:default_value, nil, &wrap_in_unquote/1)
 
@@ -1711,7 +1727,8 @@ defmodule Absinthe.Schema.Notation do
   @doc false
   # Record an implemented interface in the current scope
   def record_interface!(env, type) do
-    type = expand_ast(type, env)
+    type = type |> expand_ast(env) |> build_identifier
+
     put_attr(env.module, {:interface, type})
   end
 
@@ -1735,8 +1752,9 @@ defmodule Absinthe.Schema.Notation do
     Enum.each(types, &record_type!(env, &1))
   end
 
-  defp record_type!(env, type) do
-    type = expand_ast(type, env)
+  def record_type!(env, type) do
+    type = type |> expand_ast(env) |> build_identifier()
+
     put_attr(env.module, {:type, type})
   end
 
@@ -1917,6 +1935,18 @@ defmodule Absinthe.Schema.Notation do
     }
   end
 
+  def build_identifier(%wrapper{} = type)
+      when wrapper in [
+             Absinthe.Blueprint.TypeReference.NonNull,
+             Absinthe.Blueprint.TypeReference.List
+           ] do
+    type
+  end
+
+  def build_identifier(type) when is_atom(type) or is_binary(type) do
+    %Absinthe.Blueprint.TypeReference.Identifier{id: type}
+  end
+
   @scope_map %{
     Schema.ObjectTypeDefinition => :object,
     Schema.FieldDefinition => :field,
diff --git a/lib/absinthe/schema/notation/sdl_render.ex b/lib/absinthe/schema/notation/sdl_render.ex
index baac5a2429..613cf25d34 100644
--- a/lib/absinthe/schema/notation/sdl_render.ex
+++ b/lib/absinthe/schema/notation/sdl_render.ex
@@ -114,9 +114,6 @@ defmodule Absinthe.Schema.Notation.SDL.Render do
 
   defp render(%Blueprint.Schema.UnionTypeDefinition{} = union_type, type_definitions) do
     Enum.map(union_type.types, fn
-      identifier when is_atom(identifier) ->
-        render(%Blueprint.TypeReference.Identifier{id: identifier}, type_definitions)
-
       %Blueprint.TypeReference.Name{} = ref ->
         render(ref, type_definitions)
 
@@ -246,10 +243,6 @@ defmodule Absinthe.Schema.Notation.SDL.Render do
     raise "Unexpected nil"
   end
 
-  defp render(identifier, type_definitions) when is_atom(identifier) do
-    render(%Blueprint.TypeReference.Identifier{id: identifier}, type_definitions)
-  end
-
   # SDL Syntax Helpers
 
   defp directives([], _) do
@@ -329,11 +322,18 @@ defmodule Absinthe.Schema.Notation.SDL.Render do
     interface_names =
       case interface do
         %{interface_blueprints: [], interfaces: identifiers} ->
-          Enum.map(identifiers, fn identifier ->
-            Enum.find_value(type_definitions, fn
-              %{identifier: ^identifier, name: name} -> name
-              _ -> nil
-            end)
+          Enum.map(identifiers, fn
+            %{id: identifier} ->
+              Enum.find_value(type_definitions, fn
+                %{identifier: ^identifier, name: name} -> name
+                _ -> nil
+              end)
+
+            identifier ->
+              Enum.find_value(type_definitions, fn
+                %{identifier: ^identifier, name: name} -> name
+                _ -> nil
+              end)
           end)
 
         %{interface_blueprints: blueprints} ->
diff --git a/test/absinthe/language/object_type_definition_test.exs b/test/absinthe/language/object_type_definition_test.exs
index bd3b882305..46a5710db9 100644
--- a/test/absinthe/language/object_type_definition_test.exs
+++ b/test/absinthe/language/object_type_definition_test.exs
@@ -54,7 +54,7 @@ defmodule Absinthe.Language.ObjectTypeDefinitionTest do
 
       assert %Blueprint.Schema.ObjectTypeDefinition{
                name: "Person",
-               interfaces: [:entity],
+               interfaces: [%Blueprint.TypeReference.Identifier{id: :entity}],
                interface_blueprints: [%Blueprint.TypeReference.Name{name: "Entity"}]
              } = rep
     end
@@ -72,7 +72,7 @@ defmodule Absinthe.Language.ObjectTypeDefinitionTest do
 
       assert %Blueprint.Schema.ObjectTypeDefinition{
                name: "Person",
-               interfaces: [:entity],
+               interfaces: [%Blueprint.TypeReference.Identifier{id: :entity}],
                interface_blueprints: [%Blueprint.TypeReference.Name{name: "Entity"}],
                directives: [%{name: "description"}]
              } = rep
diff --git a/test/absinthe/phase/document/validation/arguments_of_correct_type_test.exs b/test/absinthe/phase/document/validation/arguments_of_correct_type_test.exs
index 4eb2b69867..4656d47ec7 100644
--- a/test/absinthe/phase/document/validation/arguments_of_correct_type_test.exs
+++ b/test/absinthe/phase/document/validation/arguments_of_correct_type_test.exs
@@ -1003,7 +1003,6 @@ defmodule Absinthe.Phase.Document.Validation.ArgumentsOfCorrectTypeTest do
       )
     end
 
-    @tag :o
     test "Invalid scalar input on mutation, no suggestion, custom error" do
       assert_fails_validation(
         """
diff --git a/test/absinthe/schema/notation/experimental/argument_test.exs b/test/absinthe/schema/notation/experimental/argument_test.exs
index a4e2a03ac7..ee2c88323c 100644
--- a/test/absinthe/schema/notation/experimental/argument_test.exs
+++ b/test/absinthe/schema/notation/experimental/argument_test.exs
@@ -28,12 +28,12 @@ defmodule Absinthe.Schema.Notation.Experimental.ArgumentTest do
 
   describe "arg" do
     test "with a bare type" do
-      assert %{name: "plain", description: nil, type: :string, identifier: :plain} =
+      assert %{name: "plain", description: nil, type: %{id: :string}, identifier: :plain} =
                lookup_argument(Definition, :obj, :field, :plain)
     end
 
     test "with attrs" do
-      assert %{name: "HasAttrs", type: :boolean, identifier: :with_attrs} =
+      assert %{name: "HasAttrs", type: %{id: :boolean}, identifier: :with_attrs} =
                lookup_argument(Definition, :obj, :field, :with_attrs)
     end
 
diff --git a/test/absinthe/schema/notation/experimental/field_test.exs b/test/absinthe/schema/notation/experimental/field_test.exs
index df786121b9..77cbd0e941 100644
--- a/test/absinthe/schema/notation/experimental/field_test.exs
+++ b/test/absinthe/schema/notation/experimental/field_test.exs
@@ -38,22 +38,22 @@ defmodule Absinthe.Schema.Notation.Experimental.FieldTest do
 
   describe "field" do
     test "without a body and with a bare type" do
-      assert %{name: "plain", description: nil, type: :string, identifier: :plain} =
+      assert %{name: "plain", description: nil, type: %{id: :string}, identifier: :plain} =
                lookup_field(Definition, :obj, :plain)
     end
 
     test "with a body and with a bare type" do
-      assert %{name: "with_block", type: :string, identifier: :with_block} =
+      assert %{name: "with_block", type: %{id: :string}, identifier: :with_block} =
                lookup_field(Definition, :obj, :with_block)
     end
 
     test "with attrs and without a body" do
-      assert %{name: "HasAttrs", type: :boolean, identifier: :with_attrs} =
+      assert %{name: "HasAttrs", type: %{id: :boolean}, identifier: :with_attrs} =
                lookup_field(Definition, :obj, :with_attrs)
     end
 
     test "with attrs and with a body" do
-      assert %{name: "HasAttrsAndBody", type: :boolean, identifier: :with_attrs_and_body} =
+      assert %{name: "HasAttrsAndBody", type: %{id: :boolean}, identifier: :with_attrs_and_body} =
                lookup_field(Definition, :obj, :with_attrs_and_body)
     end