diff --git a/crates/fayalite-proc-macros-impl/src/lib.rs b/crates/fayalite-proc-macros-impl/src/lib.rs
index 903983f..194dbf3 100644
--- a/crates/fayalite-proc-macros-impl/src/lib.rs
+++ b/crates/fayalite-proc-macros-impl/src/lib.rs
@@ -78,7 +78,6 @@ mod kw {
     custom_keyword!(output);
     custom_keyword!(reg_builder);
     custom_keyword!(reset);
-    custom_keyword!(reset_default);
     custom_keyword!(skip);
     custom_keyword!(target);
     custom_keyword!(wire);
diff --git a/crates/fayalite-proc-macros-impl/src/module/transform_body.rs b/crates/fayalite-proc-macros-impl/src/module/transform_body.rs
index 1f9565a..6e99e87 100644
--- a/crates/fayalite-proc-macros-impl/src/module/transform_body.rs
+++ b/crates/fayalite-proc-macros-impl/src/module/transform_body.rs
@@ -265,11 +265,6 @@ pub(crate) enum RegBuilderReset {
         paren: Paren,
         init_expr: Box<Expr>,
     },
-    ResetDefault {
-        dot_token: Token![.],
-        reset_default: kw::reset_default,
-        paren: Paren,
-    },
 }
 
 impl_fold! {
@@ -286,11 +281,6 @@ impl_fold! {
             paren: Paren,
             init_expr: Box<Expr>,
         },
-        ResetDefault {
-            dot_token: Token![.],
-            reset_default: kw::reset_default,
-            paren: Paren,
-        },
     }
 }
 
@@ -312,11 +302,6 @@ impl Parse for RegBuilderReset {
                 paren: parenthesized!(paren_contents in input),
                 init_expr: paren_contents.call(parse_single_fn_arg)?,
             }),
-            RegBuilderMethod::ResetDefault(reset_default) => Ok(Self::ResetDefault {
-                dot_token,
-                reset_default,
-                paren: parenthesized!(paren_contents in input),
-            }),
         }
     }
 }
@@ -344,15 +329,6 @@ impl ToTokens for RegBuilderReset {
                 reset.to_tokens(tokens);
                 paren.surround(tokens, |tokens| init_expr.to_tokens(tokens));
             }
-            RegBuilderReset::ResetDefault {
-                dot_token,
-                reset_default,
-                paren,
-            } => {
-                dot_token.to_tokens(tokens);
-                reset_default.to_tokens(tokens);
-                paren.surround(tokens, |_| {});
-            }
         }
     }
 }
@@ -401,8 +377,6 @@ make_builder_method_enum! {
         NoReset(no_reset),
         #[cond = need_reset]
         Reset(reset),
-        #[cond = need_reset]
-        ResetDefault(reset_default),
     }
 }
 
@@ -445,17 +419,13 @@ impl HdlLetKindRegBuilder {
         let mut clock_domain = None;
         match RegBuilderMethod::parse_dot_prefixed(&input.fork(), true, true)?.1 {
             RegBuilderMethod::ClockDomain(_) => clock_domain = Some(input.parse()?),
-            RegBuilderMethod::NoReset(_)
-            | RegBuilderMethod::Reset(_)
-            | RegBuilderMethod::ResetDefault(_) => {}
+            RegBuilderMethod::NoReset(_) | RegBuilderMethod::Reset(_) => {}
         }
         let reset = input.parse()?;
         if clock_domain.is_none() {
             match RegBuilderMethod::parse_dot_prefixed(&input.fork(), true, false)?.1 {
                 RegBuilderMethod::ClockDomain(_) => clock_domain = Some(input.parse()?),
-                RegBuilderMethod::NoReset(_)
-                | RegBuilderMethod::Reset(_)
-                | RegBuilderMethod::ResetDefault(_) => unreachable!(),
+                RegBuilderMethod::NoReset(_) | RegBuilderMethod::Reset(_) => unreachable!(),
             }
         }
         Ok(Self {
@@ -1370,7 +1340,7 @@ impl Visitor<'_> {
                 no_reset.to_tokens(&mut expr);
                 paren.surround(&mut expr, |expr| ty_expr.to_tokens(expr));
             }
-            RegBuilderReset::Reset { .. } | RegBuilderReset::ResetDefault { .. } => {
+            RegBuilderReset::Reset { .. } => {
                 hdl_let.kind.reset.to_tokens(&mut expr);
             }
         }
diff --git a/crates/fayalite/src/expr/ops.rs b/crates/fayalite/src/expr/ops.rs
index 4814d2d..e5d3d9b 100644
--- a/crates/fayalite/src/expr/ops.rs
+++ b/crates/fayalite/src/expr/ops.rs
@@ -1236,10 +1236,11 @@ macro_rules! impl_dyn_shl {
             }
         }
 
-        impl_binary_op_trait! {
-            #[generics(LhsWidth: Size, RhsWidth: Size)]
-            fn Shl::shl(lhs: $ty<LhsWidth>, rhs: UIntType<RhsWidth>) -> $ty {
-                $name::new(Expr::as_dyn_int(lhs), Expr::as_dyn_int(rhs)).to_expr()
+        impl<LhsWidth: Size, RhsWidth: Size> Shl<Expr<UIntType<RhsWidth>>> for Expr<$ty<LhsWidth>> {
+            type Output = Expr<$ty>;
+
+            fn shl(self, rhs: Expr<UIntType<RhsWidth>>) -> Self::Output {
+                $name::new(Expr::as_dyn_int(self), Expr::as_dyn_int(rhs)).to_expr()
             }
         }
     };
@@ -1308,10 +1309,11 @@ macro_rules! impl_dyn_shr {
             }
         }
 
-        impl_binary_op_trait! {
-            #[generics(LhsWidth: Size, RhsWidth: Size)]
-            fn Shr::shr(lhs: $ty<LhsWidth>, rhs: UIntType<RhsWidth>) -> $ty<LhsWidth> {
-                $name::new(lhs, Expr::as_dyn_int(rhs)).to_expr()
+        impl<LhsWidth: Size, RhsWidth: Size> Shr<Expr<UIntType<RhsWidth>>> for Expr<$ty<LhsWidth>> {
+            type Output = Expr<$ty<LhsWidth>>;
+
+            fn shr(self, rhs: Expr<UIntType<RhsWidth>>) -> Self::Output {
+                $name::new(self, Expr::as_dyn_int(rhs)).to_expr()
             }
         }
     };
diff --git a/crates/fayalite/src/int.rs b/crates/fayalite/src/int.rs
index 2950086..b48f617 100644
--- a/crates/fayalite/src/int.rs
+++ b/crates/fayalite/src/int.rs
@@ -18,6 +18,7 @@ use std::{
     borrow::{BorrowMut, Cow},
     fmt,
     marker::PhantomData,
+    num::NonZero,
     ops::{Bound, Index, Not, Range, RangeBounds, RangeInclusive},
     sync::Arc,
 };
@@ -468,7 +469,11 @@ impl SInt {
 }
 
 macro_rules! impl_prim_int {
-    ($prim_int:ident, $ty:ty) => {
+    (
+        $(#[$meta:meta])*
+        $prim_int:ident, $ty:ty
+    ) => {
+        $(#[$meta])*
         impl ToExpr for $prim_int {
             type Type = $ty;
 
@@ -479,6 +484,17 @@ macro_rules! impl_prim_int {
                 )
             }
         }
+        $(#[$meta])*
+        impl ToExpr for NonZero<$prim_int> {
+            type Type = $ty;
+
+            fn to_expr(&self) -> Expr<Self::Type> {
+                <$ty>::le_bytes_to_expr_wrapping(
+                    &self.get().to_le_bytes(),
+                    <$ty as BoolOrIntType>::Width::VALUE,
+                )
+            }
+        }
     };
 }
 
@@ -493,6 +509,16 @@ impl_prim_int!(i32, SInt<32>);
 impl_prim_int!(i64, SInt<64>);
 impl_prim_int!(i128, SInt<128>);
 
+impl_prim_int!(
+    /// for portability reasons, [`usize`] always translates to [`UInt<64>`]
+    usize, UInt<64>
+);
+
+impl_prim_int!(
+    /// for portability reasons, [`isize`] always translates to [`SInt<64>`]
+    isize, SInt<64>
+);
+
 pub trait BoolOrIntType: Type + sealed::BoolOrIntTypeSealed {
     type Width: Size;
     type Signed: GenericConstBool;