proper Token.Declaration for internal_declaration;

--- a/src/Pure/Isar/attrib.ML	Tue May 16 20:26:09 2023 +0200
+++ b/src/Pure/Isar/attrib.ML	Thu May 18 14:06:35 2023 +0200
@@ -237,23 +237,32 @@
 
 (* internal attribute *)
 
+fun internal_name ctxt name =
+  Token.make_src (name, Position.none) [] |> check_src ctxt |> hd;
+
+local
+
 val _ = Theory.setup
   (setup (Binding.make ("attribute", \<^here>))
-    (Scan.lift Args.internal_attribute >> Morphism.form)
+    (Scan.lift Args.internal_attribute >> Morphism.form ||
+      Scan.lift Args.internal_declaration >> (Thm.declaration_attribute o K o Morphism.form))
     "internal attribute");
 
-fun internal_name ctxt name =
-  Token.make_src (name, Position.none) [] |> check_src ctxt |> hd;
-
 val internal_attribute_name =
   internal_name (Context.the_local_context ()) "attribute";
 
-fun internal att =
+fun internal_source value =
   internal_attribute_name ::
-    [Token.make_string ("<attribute>", Position.none) |> Token.assign (SOME (Token.Attribute att))];
+    [Token.make_string ("<attribute>", Position.none) |> Token.assign (SOME value)];
+
+in
+
+fun internal att = internal_source (Token.Attribute att);
 
 fun internal_declaration decl =
-  [([Drule.dummy_thm], [internal (fn phi => Thm.declaration_attribute (K (decl phi)))])];
+  [([Drule.dummy_thm], [internal_source (Token.Declaration decl)])];
+
+end;
 
 
 (* add/del syntax *)