diff --git a/crates/fayalite/tests/hdl_types.rs b/crates/fayalite/tests/hdl_types.rs
index b8cbff3..71450fc 100644
--- a/crates/fayalite/tests/hdl_types.rs
+++ b/crates/fayalite/tests/hdl_types.rs
@@ -1,6 +1,13 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
 use fayalite::prelude::*;
+#[cfg(todo)]
+use fayalite::{
+    bundle::BundleType,
+    enum_::EnumType,
+    int::{BoolOrIntType, IntType},
+    ty::StaticType,
+};
 use std::marker::PhantomData;
 
 #[hdl(outline_generated)]
@@ -32,13 +39,6 @@ pub struct S2<T = ()> {
     pub v: E<T>,
 }
 
-#[cfg(todo)]
-#[hdl(outline_generated)]
-pub struct S4<W: KnownSize, W2: KnownSize> {
-    pub v: UIntType<W>,
-    pub v2: SIntType<W2>,
-}
-
 // check that #[hdl] properly handles hygiene
 macro_rules! types_in_macros {
     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident, $f:ident, $A:ident, $B:ident, $C:ident, $D:ident, $E:ident, $F:ident) => {
@@ -104,3 +104,84 @@ macro_rules! types_in_macros {
 }
 
 types_in_macros!();
+
+mod bound_kind {
+    use fayalite::prelude::*;
+
+    #[hdl]
+    pub struct Type<T> {
+        v: T,
+    }
+
+    #[hdl]
+    pub struct Size<T: ::fayalite::int::Size> {
+        v: UIntType<T>,
+    }
+}
+
+macro_rules! check_bounds {
+    ($name:ident<$(#[$field:ident, $kind:ident] $var:ident: $($bound:ident +)*),*>) => {
+        #[cfg(todo)]
+        #[hdl(outline_generated)]
+        struct $name<$($var: $($bound +)*,)*> {
+            $($field: bound_kind::$kind<$var>,)*
+        }
+    };
+}
+
+check_bounds!(CheckBoundsS0<#[a, Size] A: Size +>);
+check_bounds!(CheckBoundsS1<#[a, Size] A: KnownSize +>);
+check_bounds!(CheckBoundsT0<#[a, Type] A: Type +>);
+check_bounds!(CheckBoundsT1<#[a, Type] A: BoolOrIntType +>);
+check_bounds!(CheckBoundsT2<#[a, Type] A: BundleType +>);
+check_bounds!(CheckBoundsT3<#[a, Type] A: EnumType +>);
+check_bounds!(CheckBoundsT4<#[a, Type] A: IntType +>);
+check_bounds!(CheckBoundsT5<#[a, Type] A: StaticType +>);
+check_bounds!(CheckBoundsSS0<#[a, Size] A: Size +, #[b, Size] B: Size +>);
+check_bounds!(CheckBoundsSS1<#[a, Size] A: KnownSize +, #[b, Size] B: Size +>);
+check_bounds!(CheckBoundsST0<#[a, Size] A: Size +, #[b, Type] B: Type +>);
+check_bounds!(CheckBoundsST1<#[a, Size] A: KnownSize +, #[b, Type] B: Type +>);
+check_bounds!(CheckBoundsTS0<#[a, Type] A: Type +, #[b, Size] B: Size +>);
+check_bounds!(CheckBoundsTS1<#[a, Type] A: BoolOrIntType +, #[b, Size] B: Size +>);
+check_bounds!(CheckBoundsTS2<#[a, Type] A: BundleType +, #[b, Size] B: Size +>);
+check_bounds!(CheckBoundsTS3<#[a, Type] A: EnumType +, #[b, Size] B: Size +>);
+check_bounds!(CheckBoundsTS4<#[a, Type] A: IntType +, #[b, Size] B: Size +>);
+check_bounds!(CheckBoundsTS5<#[a, Type] A: StaticType +, #[b, Size] B: Size +>);
+check_bounds!(CheckBoundsTT0<#[a, Type] A: Type +, #[b, Type] B: Type +>);
+check_bounds!(CheckBoundsTT1<#[a, Type] A: BoolOrIntType +, #[b, Type] B: Type +>);
+check_bounds!(CheckBoundsTT2<#[a, Type] A: BundleType +, #[b, Type] B: Type +>);
+check_bounds!(CheckBoundsTT3<#[a, Type] A: EnumType +, #[b, Type] B: Type +>);
+check_bounds!(CheckBoundsTT4<#[a, Type] A: IntType +, #[b, Type] B: Type +>);
+check_bounds!(CheckBoundsTT5<#[a, Type] A: StaticType +, #[b, Type] B: Type +>);
+check_bounds!(CheckBoundsSSS0<#[a, Size] A: Size +, #[b, Size] B: Size +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsSSS1<#[a, Size] A: KnownSize +, #[b, Size] B: Size +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsSST0<#[a, Size] A: Size +, #[b, Size] B: Size +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsSST1<#[a, Size] A: KnownSize +, #[b, Size] B: Size +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsSTS0<#[a, Size] A: Size +, #[b, Type] B: Type +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsSTS1<#[a, Size] A: KnownSize +, #[b, Type] B: Type +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsSTT0<#[a, Size] A: Size +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsSTT1<#[a, Size] A: KnownSize +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTSS0<#[a, Type] A: Type +, #[b, Size] B: Size +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTSS1<#[a, Type] A: BoolOrIntType +, #[b, Size] B: Size +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTSS2<#[a, Type] A: BundleType +, #[b, Size] B: Size +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTSS3<#[a, Type] A: EnumType +, #[b, Size] B: Size +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTSS4<#[a, Type] A: IntType +, #[b, Size] B: Size +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTSS5<#[a, Type] A: StaticType +, #[b, Size] B: Size +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTST0<#[a, Type] A: Type +, #[b, Size] B: Size +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTST1<#[a, Type] A: BoolOrIntType +, #[b, Size] B: Size +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTST2<#[a, Type] A: BundleType +, #[b, Size] B: Size +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTST3<#[a, Type] A: EnumType +, #[b, Size] B: Size +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTST4<#[a, Type] A: IntType +, #[b, Size] B: Size +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTST5<#[a, Type] A: StaticType +, #[b, Size] B: Size +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTTS0<#[a, Type] A: Type +, #[b, Type] B: Type +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTTS1<#[a, Type] A: BoolOrIntType +, #[b, Type] B: Type +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTTS2<#[a, Type] A: BundleType +, #[b, Type] B: Type +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTTS3<#[a, Type] A: EnumType +, #[b, Type] B: Type +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTTS4<#[a, Type] A: IntType +, #[b, Type] B: Type +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTTS5<#[a, Type] A: StaticType +, #[b, Type] B: Type +, #[c, Size] C: Size +>);
+check_bounds!(CheckBoundsTTT0<#[a, Type] A: Type +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTTT1<#[a, Type] A: BoolOrIntType +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTTT2<#[a, Type] A: BundleType +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTTT3<#[a, Type] A: EnumType +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTTT4<#[a, Type] A: IntType +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
+check_bounds!(CheckBoundsTTT5<#[a, Type] A: StaticType +, #[b, Type] B: Type +, #[c, Type] C: Type +>);