[wip] Implement error source dropping

.github/workflows/ci.yml

@@ -10,10 +10,6 @@ name: Build & Tests
 
 on:
   pull_request:
-  push:
-    branches:
-      - main
-      - v0.6.x
   merge_group:
 
 permissions: read-all
@@ -56,10 +52,6 @@ jobs:
           # which a particular feature is supported.
           "zerocopy-core-error",
           "zerocopy-diagnostic-on-unimplemented",
-          "zerocopy-generic-bounds-in-const-fn",
-          "zerocopy-target-has-atomics",
-          "zerocopy-aarch64-simd",
-          "zerocopy-panic-in-const-and-vec-try-reserve"
         ]
         target: [
           "i686-unknown-linux-gnu",
@@ -93,14 +85,6 @@ jobs:
             features: "--all-features"
           - toolchain: "zerocopy-diagnostic-on-unimplemented"
             features: "--all-features"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            features: "--all-features"
-          - toolchain: "zerocopy-target-has-atomics"
-            features: "--all-features"
-          - toolchain: "zerocopy-aarch64-simd"
-            features: "--all-features"
-          - toolchain: "zerocopy-panic-in-const-and-vec-try-reserve"
-            features: "--all-features"
           # Exclude any combination for the zerocopy-derive crate which
           # uses zerocopy features.
           - crate: "zerocopy-derive"
@@ -117,36 +101,6 @@ jobs:
             toolchain: "zerocopy-core-error"
           - crate: "zerocopy-derive"
             toolchain: "zerocopy-diagnostic-on-unimplemented"
-          - crate: "zerocopy-derive"
-            toolchain: "zerocopy-generic-bounds-in-const-fn"
-          - crate: "zerocopy-derive"
-            toolchain: "zerocopy-target-has-atomics"
-          - crate: "zerocopy-derive"
-            toolchain: "zerocopy-aarch64-simd"
-          - crate: "zerocopy-derive"
-            toolchain: "zerocopy-panic-in-const-and-vec-try-reserve"
-          # Exclude non-aarch64 targets from the `zerocopy-aarch64-simd`
-          # toolchain.
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "i686-unknown-linux-gnu"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "x86_64-unknown-linux-gnu"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "arm-unknown-linux-gnueabi"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "powerpc-unknown-linux-gnu"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "powerpc64-unknown-linux-gnu"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "riscv64gc-unknown-linux-gnu"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "s390x-unknown-linux-gnu"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "x86_64-pc-windows-msvc"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "thumbv6m-none-eabi"
-          - toolchain: "zerocopy-aarch64-simd"
-            target: "wasm32-wasi"
           # Exclude most targets targets from the `zerocopy-core-error`
           # toolchain since the `zerocopy-core-error` feature is unrelated to
           # compilation target. This only leaves i686 and x86_64 targets.
@@ -190,28 +144,6 @@ jobs:
             target: "thumbv6m-none-eabi"
           - toolchain: "zerocopy-diagnostic-on-unimplemented"
             target: "wasm32-wasi"
-          # Exclude most targets targets from the
-          # `zerocopy-generic-bounds-in-const-fn` toolchain since the
-          # `zerocopy-generic-bounds-in-const-fn` feature is unrelated to
-          # compilation target. This only leaves i686 and x86_64 targets.
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "arm-unknown-linux-gnueabi"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "aarch64-unknown-linux-gnu"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "powerpc-unknown-linux-gnu"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "powerpc64-unknown-linux-gnu"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "riscv64gc-unknown-linux-gnu"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "s390x-unknown-linux-gnu"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "x86_64-pc-windows-msvc"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "thumbv6m-none-eabi"
-          - toolchain: "zerocopy-generic-bounds-in-const-fn"
-            target: "wasm32-wasi"
           # Exclude `thumbv6m-none-eabi` combined with any feature that implies
           # the `std` feature since `thumbv6m-none-eabi` does not include a
           # pre-compiled std.
@@ -259,7 +191,7 @@ jobs:
         set -eo pipefail
         # Override the exising `syn` dependency with one which requires an exact
         # version.
-        cargo add -p zerocopy-derive 'syn@=2.0.46'
+        cargo add -p zerocopy-derive 'syn@=2.0.79'
 
     - name: Configure environment variables
       run: |
@@ -321,7 +253,7 @@ jobs:
           components: clippy, rust-src ${{ matrix.toolchain == 'nightly' && ', miri' || '' }}
 
     - name: Rust Cache
-      uses: Swatinem/rust-cache@23bce251a8cd2ffc3c1075eaa2367cf899916d84 # v2.7.3
+      uses: Swatinem/rust-cache@82a92a6e8fbeee089604da2575dc567ae9ddeaab # v2.7.5
       with:
         key: "${{ matrix.target }}"
 
@@ -594,7 +526,7 @@ jobs:
           echo "RUSTFLAGS=$RUSTFLAGS" >> $GITHUB_ENV
           echo "ZC_TOOLCHAIN=$ZC_TOOLCHAIN" >> $GITHUB_ENV
       - name: Rust Cache
-        uses: Swatinem/rust-cache@23bce251a8cd2ffc3c1075eaa2367cf899916d84 # v2.7.3
+        uses: Swatinem/rust-cache@82a92a6e8fbeee089604da2575dc567ae9ddeaab # v2.7.5
         with:
           key: aarch64_be-unknown-linux-gnu
       - name: Install stable Rust for use in 'cargo.sh'
@@ -681,7 +613,7 @@ jobs:
           #
           # TODO(#1595): Debug why this step is still necessary after #1564 and
           # maybe remove it.
-          cargo add -p zerocopy-derive 'syn@=2.0.46' &> /dev/null
+          cargo add -p zerocopy-derive 'syn@=2.0.79' &> /dev/null
 
           cargo check --workspace --tests            &> /dev/null &
           cargo metadata                             &> /dev/null &

.github/workflows/roll-pinned-toolchain-versions.yml

@@ -35,7 +35,7 @@ jobs:
       fail-fast: false
       matrix:
         toolchain: ["stable", "nightly"]
-        branch: ["main"]
+        branch: ["main", "v0.8.x"]
     name: Roll pinned toolchain ${{ matrix.toolchain }} version on ${{ matrix.branch }}
     steps:
       - name: Checkout code

.github/workflows/scorecard.yml

@@ -66,6 +66,6 @@ jobs:
 
       # Upload the results to GitHub's code scanning dashboard.
       - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@c36620d31ac7c881962c3d9dd939c40ec9434f2b # v3.26.12
+        uses: github/codeql-action/upload-sarif@f779452ac5af1c261dce0346a8f964149f49322b # v3.26.13
         with:
           sarif_file: results.sarif

Cargo.toml

@@ -15,14 +15,14 @@
 [package]
 edition = "2021"
 name = "zerocopy"
-version = "0.8.5"
+version = "0.9.0-alpha.0"
 authors = ["Joshua Liebow-Feeser <[email protected]>"]
 description = "Zerocopy makes zero-cost memory manipulation effortless. We write \"unsafe\" so you don't have to."
 categories = ["embedded", "encoding", "no-std::no-alloc", "parsing", "rust-patterns"]
 keywords = ["cast", "convert", "transmute", "transmutation", "type-punning"]
 license = "BSD-2-Clause OR Apache-2.0 OR MIT"
 repository = "https://github.com/google/zerocopy"
-rust-version = "1.56.0"
+rust-version = "1.65.0"
 
 exclude = [".*"]
 
@@ -38,25 +38,10 @@ zerocopy-core-error = "1.81.0"
 # From 1.78.0, Rust supports the `#[diagnostic::on_unimplemented]` attribute.
 zerocopy-diagnostic-on-unimplemented = "1.78.0"
 
-# From 1.61.0, Rust supports generic types with trait bounds in `const fn`.
-zerocopy-generic-bounds-in-const-fn = "1.61.0"
-
-# From 1.60.0, Rust supports `cfg(target_has_atomics)`, which allows us to
-# detect whether a target supports particular sets of atomics.
-zerocopy-target-has-atomics = "1.60.0"
-
-# When the "simd" feature is enabled, include SIMD types from the
-# `core::arch::aarch64` module, which was stabilized in 1.59.0. On earlier Rust
-# versions, these types require the "simd-nightly" feature.
-zerocopy-aarch64-simd = "1.59.0"
-
-# Permit panicking in `const fn`s and calling `Vec::try_reserve`.
-zerocopy-panic-in-const-and-vec-try-reserve = "1.57.0"
-
 [package.metadata.ci]
 # The versions of the stable and nightly compiler toolchains to use in CI.
 pinned-stable = "1.81.0"
-pinned-nightly = "nightly-2024-10-11"
+pinned-nightly = "nightly-2024-10-14"
 
 [package.metadata.docs.rs]
 all-features = true
@@ -77,26 +62,26 @@ std = ["alloc"]
 __internal_use_only_features_that_work_on_stable = ["alloc", "derive", "simd", "std"]
 
 [dependencies]
-zerocopy-derive = { version = "=0.8.5", path = "zerocopy-derive", optional = true }
+zerocopy-derive = { version = "=0.9.0-alpha.0", path = "zerocopy-derive", optional = true }
 
 # The "associated proc macro pattern" ensures that the versions of zerocopy and
 # zerocopy-derive remain equal, even if the 'derive' feature isn't used.
 # See: https://github.com/matklad/macro-dep-test
 [target.'cfg(any())'.dependencies]
-zerocopy-derive = { version = "=0.8.5", path = "zerocopy-derive" }
+zerocopy-derive = { version = "=0.9.0-alpha.0", path = "zerocopy-derive" }
 
 [dev-dependencies]
-itertools = "0.11"
+itertools = "0.13.0"
 rand = { version = "0.8.5", default-features = false, features = ["small_rng"] }
-rustversion = "1.0"
-static_assertions = "1.1"
+rustversion = "1.0.17"
+static_assertions = "1.1.0"
 testutil = { path = "testutil" }
 # Pinned to a specific version so that the version used for local development
 # and the version used in CI are guaranteed to be the same. Future versions
 # sometimes change the output format slightly, so a version mismatch can cause
 # CI test failures.
-trybuild = { version = "=1.0.89", features = ["diff"] }
+trybuild = { version = "=1.0.90", features = ["diff"] }
 # In tests, unlike in production, zerocopy-derive is not optional
-zerocopy-derive = { version = "=0.8.5", path = "zerocopy-derive" }
+zerocopy-derive = { version = "=0.9.0-alpha.0", path = "zerocopy-derive" }
 # TODO(#381) Remove this dependency once we have our own layout gadgets.
 elain = "0.3.0"

src/byteorder.rs

@@ -539,33 +539,29 @@ example of how it can be used for parsing UDP packets.
         }
 
         impl<O: ByteOrder> $name<O> {
-            maybe_const_trait_bounded_fn! {
-                /// Constructs a new value, possibly performing an endianness
-                /// swap to guarantee that the returned value has endianness
-                /// `O`.
-                #[must_use = "has no side effects"]
-                #[inline(always)]
-                pub const fn new(n: $native) -> $name<O> {
-                    let bytes = match O::ORDER {
-                        Order::BigEndian => $to_be_fn(n),
-                        Order::LittleEndian => $to_le_fn(n),
-                    };
+            /// Constructs a new value, possibly performing an endianness
+            /// swap to guarantee that the returned value has endianness
+            /// `O`.
+            #[must_use = "has no side effects"]
+            #[inline(always)]
+            pub const fn new(n: $native) -> $name<O> {
+                let bytes = match O::ORDER {
+                    Order::BigEndian => $to_be_fn(n),
+                    Order::LittleEndian => $to_le_fn(n),
+                };
 
-                    $name(bytes, PhantomData)
-                }
+                $name(bytes, PhantomData)
             }
 
-            maybe_const_trait_bounded_fn! {
-                /// Returns the value as a primitive type, possibly performing
-                /// an endianness swap to guarantee that the return value has
-                /// the endianness of the native platform.
-                #[must_use = "has no side effects"]
-                #[inline(always)]
-                pub const fn get(self) -> $native {
-                    match O::ORDER {
-                        Order::BigEndian => $from_be_fn(self.0),
-                        Order::LittleEndian => $from_le_fn(self.0),
-                    }
+            /// Returns the value as a primitive type, possibly performing
+            /// an endianness swap to guarantee that the return value has
+            /// the endianness of the native platform.
+            #[must_use = "has no side effects"]
+            #[inline(always)]
+            pub const fn get(self) -> $native {
+                match O::ORDER {
+                    Order::BigEndian => $from_be_fn(self.0),
+                    Order::LittleEndian => $from_le_fn(self.0),
                 }
             }
 
@@ -971,6 +967,7 @@ module!(network_endian, NetworkEndian, "network-endian");
 module!(native_endian, NativeEndian, "native-endian");
 
 #[cfg(any(test, kani))]
+#[allow(clippy::missing_const_for_fn)]
 mod tests {
     use super::*;
 
@@ -1057,8 +1054,8 @@ mod tests {
         /// themselves. This method is like `assert_eq!`, but it treats NaN
         /// values as equal.
         fn assert_eq_or_nan(self, other: Self) {
-            let slf = (!self.is_nan()).then(|| self);
-            let other = (!other.is_nan()).then(|| other);
+            let slf = (!self.is_nan()).then_some(self);
+            let other = (!other.is_nan()).then_some(other);
             assert_eq!(slf, other);
         }
     }
@@ -1088,8 +1085,8 @@ mod tests {
         /// themselves. This method is like `assert_eq!`, but it treats NaN
         /// values as equal.
         fn assert_eq_or_nan(self, other: Self) {
-            let slf = (!self.get().is_nan()).then(|| self);
-            let other = (!other.get().is_nan()).then(|| other);
+            let slf = (!self.get().is_nan()).then_some(self);
+            let other = (!other.get().is_nan()).then_some(other);
             assert_eq!(slf, other);
         }
     }
@@ -1396,11 +1393,11 @@ mod tests {
                 // For `f32` and `f64`, NaN values are not considered equal to
                 // themselves. We store `Option<f32>`/`Option<f64>` and store
                 // NaN as `None` so they can still be compared.
-                let val_or_none = |t: T| (!T::Native::is_nan(t.get())).then(|| t.get());
+                let val_or_none = |t: T| (!T::Native::is_nan(t.get())).then_some(t.get());
                 let t_t_res = val_or_none(t_t_res);
                 let t_n_res = val_or_none(t_n_res);
                 let n_t_res = val_or_none(n_t_res);
-                let n_n_res = (!T::Native::is_nan(n_n_res)).then(|| n_n_res);
+                let n_n_res = (!T::Native::is_nan(n_n_res)).then_some(n_n_res);
                 assert_eq!(t_t_res, n_n_res);
                 assert_eq!(t_n_res, n_n_res);
                 assert_eq!(n_t_res, n_n_res);
@@ -1418,7 +1415,7 @@ mod tests {
                     // NaN as `None` so they can still be compared.
                     let t_t_res = val_or_none(t_t_res);
                     let t_n_res = val_or_none(t_n_res);
-                    let n_t_res = (!T::Native::is_nan(n_t_res)).then(|| n_t_res);
+                    let n_t_res = (!T::Native::is_nan(n_t_res)).then_some(n_t_res);
                     assert_eq!(t_t_res, n_n_res);
                     assert_eq!(t_n_res, n_n_res);
                     assert_eq!(n_t_res, n_n_res);