From 3d1630b4a148ed40d6eb21691e7f5794aea7b944 Mon Sep 17 00:00:00 2001
From: David Anderson <dave@natulte.net>
Date: Sun, 16 Aug 2026 11:55:36 -0700
Subject: [PATCH 1/2] Add TryFrom bounds for all integer primitive types to
 SimdIntElement

Signed-off-by: David Anderson <dave@natulte.net>
---
 CHANGELOG.md                |  1 +
 fearless_simd/src/traits.rs | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 923f04e0..f6c1e083 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ You can find its changes [documented below](#070-2026-08-11).
 - Added lane-wise `count_ones` and `count_zeros` operations for all integer vector types and backends.
 - Added `mul_add_precise` and `mul_sub_precise` for floating-point vectors. They guarantee the infinite-precision product-plus-add rounded once, including on SIMD levels without hardware fused multiply-add instructions. They are not susceptible to the [bug](https://github.com/rust-lang/compiler-builtins/issues/1262) in Rust standard library, `std::simd` and musl libc that causes incorrect rounding for subnormal results. SSE4.2 gets SIMD emulation of these operations for better performance. ([#323][], [#324][] by [@Shnatsel][])
 - Documented the storage representation of the SIMD vector types. The documented representation will not change without a semver major version change.
+- Added `TryFrom` bounds to `SimdIntElement`, allowing attempted conversion from all primitive integer types.
 
 ### Changed
 
diff --git a/fearless_simd/src/traits.rs b/fearless_simd/src/traits.rs
index 49d90a94..d94deb4c 100644
--- a/fearless_simd/src/traits.rs
+++ b/fearless_simd/src/traits.rs
@@ -6,6 +6,7 @@
     reason = "TODO: https://github.com/linebender/fearless_simd/issues/40"
 )]
 use crate::{Simd, SimdBase, seal::Seal};
+use core::error::Error;
 use core::fmt::{Binary, Debug, Display, LowerExp, UpperExp};
 use core::iter::{Product, Sum};
 use core::ops::{
@@ -219,6 +220,18 @@ pub trait SimdIntElement:
     + BitOrAssign<Self>
     + BitXor<Self, Output = Self>
     + BitXorAssign<Self>
+    + TryFrom<u8, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<u16, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<u32, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<u64, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<u128, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<usize, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<i8, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<i16, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<i32, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<i64, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<i128, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<isize, Error: Copy + Clone + Error + Eq + PartialEq>
     + for<'a> Shl<&'a usize, Output = Self>
     + for<'a> ShlAssign<&'a usize>
     + for<'a> Shr<&'a usize, Output = Self>

From fc72a3d42d7bddfee9b4a4623ade0f8c7cc7e543 Mon Sep 17 00:00:00 2001
From: "Sergey \"Shnatsel\" Davidoff" <shnatsel@gmail.com>
Date: Wed, 26 Aug 2026 22:39:05 +0100
Subject: [PATCH 2/2] More succinct bounds: Eq implies PartialEq, Copy implies
 Clone

---
 fearless_simd/src/traits.rs | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/fearless_simd/src/traits.rs b/fearless_simd/src/traits.rs
index d94deb4c..96da83ec 100644
--- a/fearless_simd/src/traits.rs
+++ b/fearless_simd/src/traits.rs
@@ -220,18 +220,18 @@ pub trait SimdIntElement:
     + BitOrAssign<Self>
     + BitXor<Self, Output = Self>
     + BitXorAssign<Self>
-    + TryFrom<u8, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<u16, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<u32, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<u64, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<u128, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<usize, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<i8, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<i16, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<i32, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<i64, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<i128, Error: Copy + Clone + Error + Eq + PartialEq>
-    + TryFrom<isize, Error: Copy + Clone + Error + Eq + PartialEq>
+    + TryFrom<u8, Error: Copy + Error + Eq>
+    + TryFrom<u16, Error: Copy + Error + Eq>
+    + TryFrom<u32, Error: Copy + Error + Eq>
+    + TryFrom<u64, Error: Copy + Error + Eq>
+    + TryFrom<u128, Error: Copy + Error + Eq>
+    + TryFrom<usize, Error: Copy + Error + Eq>
+    + TryFrom<i8, Error: Copy + Error + Eq>
+    + TryFrom<i16, Error: Copy + Error + Eq>
+    + TryFrom<i32, Error: Copy + Error + Eq>
+    + TryFrom<i64, Error: Copy + Error + Eq>
+    + TryFrom<i128, Error: Copy + Error + Eq>
+    + TryFrom<isize, Error: Copy + Error + Eq>
     + for<'a> Shl<&'a usize, Output = Self>
     + for<'a> ShlAssign<&'a usize>
     + for<'a> Shr<&'a usize, Output = Self>