ctutils: use cast_(un)signed; MSRV 1.87

.github/workflows/ctutils.yml

@@ -33,7 +33,7 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.86.0 # MSRV
+          - 1.87.0 # MSRV
           - stable
         target:
           - thumbv7em-none-eabi
@@ -58,7 +58,7 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.86.0 # MSRV
+          - 1.87.0 # MSRV
           - stable
     steps:
       - uses: actions/checkout@v7

ctutils/Cargo.toml

@@ -14,7 +14,7 @@ categories = ["cryptography", "no-std"]
 keywords = ["constant-time", "crypto", "intrinsics"]
 readme = "README.md"
 edition = "2024"
-rust-version = "1.86"
+rust-version = "1.87"
 
 [dependencies]
 cmov = "0.5.3"

ctutils/README.md

@@ -79,7 +79,7 @@ dual licensed as above, without any additional terms or conditions.
 [docs-image]: https://docs.rs/ctutils/badge.svg
 [docs-link]: https://docs.rs/ctutils/
 [license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg
-[msrv-image]: https://img.shields.io/badge/rustc-1.86+-blue.svg
+[msrv-image]: https://img.shields.io/badge/rustc-1.87+-blue.svg
 [build-image]: https://github.com/RustCrypto/utils/actions/workflows/ctutils.yml/badge.svg
 [build-link]: https://github.com/RustCrypto/utils/actions/workflows/ctutils.yml
 [chat-image]: https://img.shields.io/badge/zulip-join_chat-blue.svg

ctutils/src/choice.rs

@@ -108,10 +108,8 @@ impl Choice {
     /// Returns [`Choice::TRUE`] if `x == y`, and [`Choice::FALSE`] otherwise.
     #[inline]
     #[must_use]
-    #[allow(clippy::cast_sign_loss)]
     pub const fn from_i64_eq(x: i64, y: i64) -> Self {
-        // TODO(tarcieri): use `cast_unsigned` when MSRV is 1.87
-        Self::from_u64_nz(x as u64 ^ y as u64).not()
+        Self::from_u64_nz(x.cast_unsigned() ^ y.cast_unsigned()).not()
     }
 
     // u8
@@ -309,10 +307,9 @@ impl Choice {
     /// and can't use the trait. The former will provide better constant-time assurances.
     #[inline]
     #[must_use]
-    #[allow(clippy::cast_possible_wrap, clippy::cast_sign_loss)]
     pub const fn select_i64(self, a: i64, b: i64) -> i64 {
-        // TODO(tarcieri): use `cast_signed` when MSRV is 1.87
-        self.select_u64(a as u64, b as u64) as i64
+        self.select_u64(a.cast_unsigned(), b.cast_unsigned())
+            .cast_signed()
     }
 
     /// `const fn` helper: return `b` if `self` is [`Choice::TRUE`], otherwise return `a`.

ctutils/src/traits/ct_gt.rs

@@ -55,13 +55,11 @@ impl CtGt for cmp::Ordering {
     #[inline]
     #[allow(clippy::arithmetic_side_effects, clippy::cast_sign_loss)]
     fn ct_gt(&self, other: &Self) -> Choice {
-        // No impl of `CtGt` for `i8`, so use `u8`
-        // TODO(tarcieri): use `cast_signed` when MSRV is 1.87
         let a = (*self as i8) + 1;
         let b = (*other as i8) + 1;
 
-        // TODO(tarcieri): use `cast_unsigned` when MSRV is 1.87
-        (a as u8).ct_gt(&(b as u8))
+        // No impl of `CtGt` for `i8`, so use `u8`
+        a.cast_unsigned().ct_gt(&b.cast_unsigned())
     }
 }
 

ctutils/src/traits/ct_lt.rs

@@ -55,13 +55,11 @@ impl CtLt for cmp::Ordering {
     #[inline]
     #[allow(clippy::arithmetic_side_effects, clippy::cast_sign_loss)]
     fn ct_lt(&self, other: &Self) -> Choice {
-        // No impl of `CtLt` for `i8`, so use `u8`
-        // TODO(tarcieri): use `cast_signed` when MSRV is 1.87
         let a = (*self as i8) + 1;
         let b = (*other as i8) + 1;
 
-        // TODO(tarcieri): use `cast_unsigned` when MSRV is 1.87
-        (a as u8).ct_lt(&(b as u8))
+        // No impl of `CtLt` for `i8`, so use `u8`
+        a.cast_unsigned().ct_lt(&b.cast_unsigned())
     }
 }