Have cfgs as part of the input to impl_unsafe_marker_for_simd (#207)

... so that the macro can correctly expand with `doc(cfg(...))` attributes under `feature = "nightly_docs"`.

src/lib.rs

@@ -79,10 +79,13 @@ macro_rules! transmute {
 /// with relevant cargo features enabled.
 #[allow(unused)]
 macro_rules! impl_unsafe_marker_for_simd {
-  (unsafe impl $trait:ident for $platform:ident :: {}) => {};
+  ($(#[cfg($cfg_predicate:meta)])? unsafe impl $trait:ident for $platform:ident :: {}) => {};
-  (unsafe impl $trait:ident for $platform:ident :: { $first_type:ident $(, $types:ident)* $(,)? }) => {
+  ($(#[cfg($cfg_predicate:meta)])? unsafe impl $trait:ident for $platform:ident :: { $first_type:ident $(, $types:ident)* $(,)? }) => {
+    $( #[cfg($cfg_predicate)] )?
+    $( #[cfg_attr(feature = "nightly_docs", doc(cfg($cfg_predicate)))] )?
     unsafe impl $trait for $platform::$first_type {}
-    impl_unsafe_marker_for_simd!(unsafe impl $trait for $platform::{ $( $types ),* });
+    $( #[cfg($cfg_predicate)] )? // To prevent recursion errors if nothing is going to be expanded anyway.
+    impl_unsafe_marker_for_simd!($( #[cfg($cfg_predicate)] )? unsafe impl $trait for $platform::{ $( $types ),* });
   };
 }
 

src/pod.rs

@@ -54,13 +54,22 @@ unsafe impl Pod for f64 {}
 unsafe impl<T: Pod> Pod for Wrapping<T> {}
 
 #[cfg(feature = "unsound_ptr_pod_impl")]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "unsound_ptr_pod_impl")))]
+#[cfg_attr(
+  feature = "nightly_docs",
+  doc(cfg(feature = "unsound_ptr_pod_impl"))
+)]
 unsafe impl<T: 'static> Pod for *mut T {}
 #[cfg(feature = "unsound_ptr_pod_impl")]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "unsound_ptr_pod_impl")))]
+#[cfg_attr(
+  feature = "nightly_docs",
+  doc(cfg(feature = "unsound_ptr_pod_impl"))
+)]
 unsafe impl<T: 'static> Pod for *const T {}
 #[cfg(feature = "unsound_ptr_pod_impl")]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "unsound_ptr_pod_impl")))]
+#[cfg_attr(
+  feature = "nightly_docs",
+  doc(cfg(feature = "unsound_ptr_pod_impl"))
+)]
 unsafe impl<T: 'static> PodInOption for NonNull<T> {}
 
 unsafe impl<T: ?Sized + 'static> Pod for PhantomData<T> {}
@@ -80,13 +89,13 @@ impl_unsafe_marker_for_array!(
   512, 1024, 2048, 4096
 );
 
-#[cfg(all(target_arch = "wasm32", feature = "wasm_simd"))]
 impl_unsafe_marker_for_simd!(
+  #[cfg(all(target_arch = "wasm32", feature = "wasm_simd"))]
   unsafe impl Pod for wasm32::{v128}
 );
 
-#[cfg(all(target_arch = "aarch64", feature = "aarch64_simd"))]
 impl_unsafe_marker_for_simd!(
+  #[cfg(all(target_arch = "aarch64", feature = "aarch64_simd"))]
   unsafe impl Pod for aarch64::{
     float32x2_t, float32x2x2_t, float32x2x3_t, float32x2x4_t, float32x4_t,
     float32x4x2_t, float32x4x3_t, float32x4x4_t, float64x1_t, float64x1x2_t,
@@ -111,16 +120,16 @@ impl_unsafe_marker_for_simd!(
   }
 );
 
-#[cfg(target_arch = "x86")]
 impl_unsafe_marker_for_simd!(
+  #[cfg(target_arch = "x86")]
   unsafe impl Pod for x86::{
     __m128i, __m128, __m128d,
     __m256i, __m256, __m256d,
   }
 );
 
-#[cfg(target_arch = "x86_64")]
 impl_unsafe_marker_for_simd!(
+  #[cfg(target_arch = "x86_64")]
   unsafe impl Pod for x86_64::{
     __m128i, __m128, __m128d,
     __m256i, __m256, __m256d,
@@ -128,7 +137,10 @@ impl_unsafe_marker_for_simd!(
 );
 
 #[cfg(feature = "nightly_portable_simd")]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "nightly_portable_simd")))]
+#[cfg_attr(
+  feature = "nightly_docs",
+  doc(cfg(feature = "nightly_portable_simd"))
+)]
 unsafe impl<T, const N: usize> Pod for core::simd::Simd<T, N>
 where
   T: core::simd::SimdElement + Pod,
@@ -136,18 +148,16 @@ where
 {
 }
 
-#[cfg(all(target_arch = "x86", feature = "nightly_stdsimd"))]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "nightly_stdsimd")))]
 impl_unsafe_marker_for_simd!(
+  #[cfg(all(target_arch = "x86", feature = "nightly_stdsimd"))]
   unsafe impl Pod for x86::{
     __m128bh, __m256bh, __m512,
     __m512bh, __m512d, __m512i,
   }
 );
 
-#[cfg(all(target_arch = "x86_64", feature = "nightly_stdsimd"))]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "nightly_stdsimd")))]
 impl_unsafe_marker_for_simd!(
+  #[cfg(all(target_arch = "x86_64", feature = "nightly_stdsimd"))]
   unsafe impl Pod for x86_64::{
     __m128bh, __m256bh, __m512,
     __m512bh, __m512d, __m512i,

src/zeroable.rs

@@ -19,8 +19,8 @@ use super::*;
 ///
 /// * `MaybeUninit<T>` was not available in 1.34.0, but is available under the
 ///   `zeroable_maybe_uninit` feature flag.
-/// * `Atomic*` types require Rust 1.60.0 or later to work on certain platforms, but is available
+/// * `Atomic*` types require Rust 1.60.0 or later to work on certain platforms,
-///   under the `zeroable_atomics` feature flag.
+///   but is available under the `zeroable_atomics` feature flag.
 /// * `[T; N]` for arbitrary `N` requires the `min_const_generics` feature flag.
 pub unsafe trait Zeroable: Sized {
   /// Calls [`zeroed`](core::mem::zeroed).
@@ -107,7 +107,10 @@ mod atomic_impls {
 }
 
 #[cfg(feature = "zeroable_maybe_uninit")]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "zeroable_maybe_uninit")))]
+#[cfg_attr(
+  feature = "nightly_docs",
+  doc(cfg(feature = "zeroable_maybe_uninit"))
+)]
 unsafe impl<T> Zeroable for core::mem::MaybeUninit<T> {}
 
 unsafe impl<A: Zeroable> Zeroable for (A,) {}
@@ -166,13 +169,13 @@ impl_unsafe_marker_for_array!(
   512, 1024, 2048, 4096
 );
 
-#[cfg(all(target_arch = "wasm32", feature = "wasm_simd"))]
 impl_unsafe_marker_for_simd!(
+  #[cfg(all(target_arch = "wasm32", feature = "wasm_simd"))]
   unsafe impl Zeroable for wasm32::{v128}
 );
 
-#[cfg(all(target_arch = "aarch64", feature = "aarch64_simd"))]
 impl_unsafe_marker_for_simd!(
+  #[cfg(all(target_arch = "aarch64", feature = "aarch64_simd"))]
   unsafe impl Zeroable for aarch64::{
     float32x2_t, float32x2x2_t, float32x2x3_t, float32x2x4_t, float32x4_t,
     float32x4x2_t, float32x4x3_t, float32x4x4_t, float64x1_t, float64x1x2_t,
@@ -197,16 +200,16 @@ impl_unsafe_marker_for_simd!(
   }
 );
 
-#[cfg(target_arch = "x86")]
 impl_unsafe_marker_for_simd!(
+  #[cfg(target_arch = "x86")]
   unsafe impl Zeroable for x86::{
     __m128i, __m128, __m128d,
     __m256i, __m256, __m256d,
   }
 );
 
-#[cfg(target_arch = "x86_64")]
 impl_unsafe_marker_for_simd!(
+  #[cfg(target_arch = "x86_64")]
     unsafe impl Zeroable for x86_64::{
         __m128i, __m128, __m128d,
         __m256i, __m256, __m256d,
@@ -214,7 +217,10 @@ impl_unsafe_marker_for_simd!(
 );
 
 #[cfg(feature = "nightly_portable_simd")]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "nightly_portable_simd")))]
+#[cfg_attr(
+  feature = "nightly_docs",
+  doc(cfg(feature = "nightly_portable_simd"))
+)]
 unsafe impl<T, const N: usize> Zeroable for core::simd::Simd<T, N>
 where
   T: core::simd::SimdElement + Zeroable,
@@ -222,18 +228,16 @@ where
 {
 }
 
-#[cfg(all(target_arch = "x86", feature = "nightly_stdsimd"))]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "nightly_std_simd")))]
 impl_unsafe_marker_for_simd!(
+  #[cfg(all(target_arch = "x86", feature = "nightly_stdsimd"))]
   unsafe impl Zeroable for x86::{
     __m128bh, __m256bh, __m512,
     __m512bh, __m512d, __m512i,
   }
 );
 
-#[cfg(all(target_arch = "x86_64", feature = "nightly_stdsimd"))]
-#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "nightly_std_simd")))]
 impl_unsafe_marker_for_simd!(
+  #[cfg(all(target_arch = "x86_64", feature = "nightly_stdsimd"))]
   unsafe impl Zeroable for x86_64::{
     __m128bh, __m256bh, __m512,
     __m512bh, __m512d, __m512i,