WIP: use HdlOption[the_type_var] or UInt[123 + n] for creating types

crates/fayalite/tests/ui/hdl_types.rs

@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
-use fayalite::ty::Value;
+use fayalite::hdl;
 
-#[derive(Value)]
+#[hdl]
 union U {
     a: (),
 }

crates/fayalite/tests/ui/hdl_types.stderr

@@ -0,0 +1,7 @@
+error: top-level #[hdl] can only be used on structs or enums
+ --> tests/ui/hdl_types.rs:5:1
+  |
+5 | #[hdl]
+  | ^^^^^^
+  |
+  = note: this error originates in the attribute macro `hdl` (in Nightly builds, run with -Z macro-backtrace for more info)

crates/fayalite/tests/ui/value_derive.stderr

@@ -1,7 +0,0 @@
-error: derive(Value) can only be used on structs or enums
- --> tests/ui/value_derive.rs:5:10
-  |
-5 | #[derive(Value)]
-  |          ^^^^^
-  |
-  = note: this error originates in the derive macro `Value` (in Nightly builds, run with -Z macro-backtrace for more info)