From 9dacfbbd69d7911910eb641ed3deb6ce723059f0 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Mon, 6 Nov 2023 08:29:16 -0800
Subject: [PATCH] Fill in more doc(cfg) attributes

---
 serde/src/de/impls.rs  | 41 +++++++++++++++++++++++++++++++++++++++++
 serde/src/de/mod.rs    |  2 ++
 serde/src/de/value.rs  | 12 ++++++++++++
 serde/src/ser/impls.rs | 38 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 93 insertions(+)

diff --git a/serde/src/de/impls.rs b/serde/src/de/impls.rs
index f4c313ef2..1f05c5333 100644
--- a/serde/src/de/impls.rs
+++ b/serde/src/de/impls.rs
@@ -39,6 +39,7 @@ impl<'de> Deserialize<'de> for () {
 }
 
 #[cfg(feature = "unstable")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "unstable")))]
 impl<'de> Deserialize<'de> for ! {
     fn deserialize<D>(_deserializer: D) -> Result<Self, D::Error>
     where
@@ -596,6 +597,7 @@ impl<'a, 'de> Visitor<'de> for StringInPlaceVisitor<'a> {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de> Deserialize<'de> for String {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -739,6 +741,7 @@ impl<'de> Visitor<'de> for CStringVisitor {
 }
 
 #[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de> Deserialize<'de> for CString {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -767,6 +770,7 @@ macro_rules! forwarded_impl {
 
 forwarded_impl! {
     #[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     (), Box<CStr>, CString::into_boxed_c_str
 }
 
@@ -978,6 +982,7 @@ fn nop_reserve<T>(_seq: T, _n: usize) {}
 
 seq_impl!(
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     BinaryHeap<T: Ord>,
     seq,
     BinaryHeap::clear,
@@ -988,6 +993,7 @@ seq_impl!(
 
 seq_impl!(
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     BTreeSet<T: Eq + Ord>,
     seq,
     BTreeSet::clear,
@@ -998,6 +1004,7 @@ seq_impl!(
 
 seq_impl!(
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     LinkedList<T>,
     seq,
     LinkedList::clear,
@@ -1008,6 +1015,7 @@ seq_impl!(
 
 seq_impl!(
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     HashSet<T: Eq + Hash, S: BuildHasher + Default>,
     seq,
     HashSet::clear,
@@ -1018,6 +1026,7 @@ seq_impl!(
 
 seq_impl!(
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     VecDeque<T>,
     seq,
     VecDeque::clear,
@@ -1029,6 +1038,7 @@ seq_impl!(
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, T> Deserialize<'de> for Vec<T>
 where
     T: Deserialize<'de>,
@@ -1432,6 +1442,7 @@ macro_rules! map_impl {
 
 map_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     BTreeMap<K: Ord, V>,
     map,
     BTreeMap::new(),
@@ -1439,6 +1450,7 @@ map_impl! {
 
 map_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     HashMap<K: Eq + Hash, V, S: BuildHasher + Default>,
     map,
     HashMap::with_capacity_and_hasher(size_hint::cautious::<(K, V)>(map.size_hint()), S::default()),
@@ -1580,6 +1592,7 @@ macro_rules! deserialize_enum {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<'de> Deserialize<'de> for net::IpAddr {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -1600,11 +1613,13 @@ impl<'de> Deserialize<'de> for net::IpAddr {
 
 parse_ip_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     net::Ipv4Addr, "IPv4 address", 4
 }
 
 parse_ip_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     net::Ipv6Addr, "IPv6 address", 16
 }
 
@@ -1631,6 +1646,7 @@ macro_rules! parse_socket_impl {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<'de> Deserialize<'de> for net::SocketAddr {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -1651,12 +1667,14 @@ impl<'de> Deserialize<'de> for net::SocketAddr {
 
 parse_socket_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     net::SocketAddrV4, "IPv4 socket address",
     |(ip, port)| net::SocketAddrV4::new(ip, port),
 }
 
 parse_socket_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     net::SocketAddrV6, "IPv6 socket address",
     |(ip, port)| net::SocketAddrV6::new(ip, port, 0, 0),
 }
@@ -1692,6 +1710,7 @@ impl<'a> Visitor<'a> for PathVisitor {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<'de: 'a, 'a> Deserialize<'de> for &'a Path {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -1746,6 +1765,7 @@ impl<'de> Visitor<'de> for PathBufVisitor {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<'de> Deserialize<'de> for PathBuf {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -1757,6 +1777,7 @@ impl<'de> Deserialize<'de> for PathBuf {
 
 forwarded_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     (), Box<Path>, PathBuf::into_boxed_path
 }
 
@@ -1818,6 +1839,7 @@ impl<'de> Visitor<'de> for OsStringVisitor {
 }
 
 #[cfg(all(feature = "std", any(unix, windows)))]
+#[cfg_attr(doc_cfg, doc(cfg(all(feature = "std", any(unix, windows)))))]
 impl<'de> Deserialize<'de> for OsString {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -1831,25 +1853,30 @@ impl<'de> Deserialize<'de> for OsString {
 
 forwarded_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     (T), Box<T>, Box::new
 }
 
 forwarded_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     (T), Box<[T]>, Vec::into_boxed_slice
 }
 
 forwarded_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     (), Box<str>, String::into_boxed_str
 }
 
 forwarded_impl! {
     #[cfg(all(feature = "std", any(unix, windows)))]
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "std", any(unix, windows)))))]
     (), Box<OsStr>, OsString::into_boxed_os_str
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, 'a, T: ?Sized> Deserialize<'de> for Cow<'a, T>
 where
     T: ToOwned,
@@ -1871,6 +1898,10 @@ where
 ///
 /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
 #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
+#[cfg_attr(
+    doc_cfg,
+    doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc"))))
+)]
 impl<'de, T: ?Sized> Deserialize<'de> for RcWeak<T>
 where
     T: Deserialize<'de>,
@@ -1889,6 +1920,10 @@ where
 ///
 /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
 #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
+#[cfg_attr(
+    doc_cfg,
+    doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc"))))
+)]
 impl<'de, T: ?Sized> Deserialize<'de> for ArcWeak<T>
 where
     T: Deserialize<'de>,
@@ -1933,6 +1968,7 @@ box_forwarded_impl! {
     ///
     /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
     #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))))]
     Rc
 }
 
@@ -1945,6 +1981,7 @@ box_forwarded_impl! {
     ///
     /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
     #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))))]
     Arc
 }
 
@@ -1968,11 +2005,13 @@ forwarded_impl! {
 
 forwarded_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     (T), Mutex<T>, Mutex::new
 }
 
 forwarded_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     (T), RwLock<T>, RwLock::new
 }
 
@@ -2127,6 +2166,7 @@ impl<'de> Deserialize<'de> for Duration {
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<'de> Deserialize<'de> for SystemTime {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -2962,6 +3002,7 @@ macro_rules! atomic_impl {
     ($($ty:ident $size:expr)*) => {
         $(
             #[cfg(any(no_target_has_atomic, target_has_atomic = $size))]
+            #[cfg_attr(doc_cfg, doc(cfg(all(feature = "std", target_has_atomic = $size))))]
             impl<'de> Deserialize<'de> for $ty {
                 fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
                 where
diff --git a/serde/src/de/mod.rs b/serde/src/de/mod.rs
index afbc23af6..c22ed070b 100644
--- a/serde/src/de/mod.rs
+++ b/serde/src/de/mod.rs
@@ -1525,6 +1525,7 @@ pub trait Visitor<'de>: Sized {
     /// `String`.
     #[inline]
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
     where
         E: Error,
@@ -1583,6 +1584,7 @@ pub trait Visitor<'de>: Sized {
     /// The default implementation forwards to `visit_bytes` and then drops the
     /// `Vec<u8>`.
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
     where
         E: Error,
diff --git a/serde/src/de/value.rs b/serde/src/de/value.rs
index 1234b8103..b229ebab7 100644
--- a/serde/src/de/value.rs
+++ b/serde/src/de/value.rs
@@ -112,6 +112,7 @@ impl Debug for Error {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl error::Error for Error {
     fn description(&self) -> &str {
         &self.err
@@ -184,12 +185,14 @@ impl<E> Debug for UnitDeserializer<E> {
 
 /// A deserializer that cannot be instantiated.
 #[cfg(feature = "unstable")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "unstable")))]
 pub struct NeverDeserializer<E> {
     never: !,
     marker: PhantomData<E>,
 }
 
 #[cfg(feature = "unstable")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "unstable")))]
 impl<'de, E> IntoDeserializer<'de, E> for !
 where
     E: de::Error,
@@ -562,6 +565,7 @@ impl<'de, E> Debug for BorrowedStrDeserializer<'de, E> {
 
 /// A deserializer holding a `String`.
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 pub struct StringDeserializer<E> {
     value: String,
     marker: PhantomData<E>,
@@ -578,6 +582,7 @@ impl<E> Clone for StringDeserializer<E> {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, E> IntoDeserializer<'de, E> for String
 where
     E: de::Error,
@@ -665,6 +670,7 @@ impl<E> Debug for StringDeserializer<E> {
 
 /// A deserializer holding a `Cow<str>`.
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 pub struct CowStrDeserializer<'a, E> {
     value: Cow<'a, str>,
     marker: PhantomData<E>,
@@ -681,6 +687,7 @@ impl<'a, E> Clone for CowStrDeserializer<'a, E> {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, 'a, E> IntoDeserializer<'de, E> for Cow<'a, str>
 where
     E: de::Error,
@@ -999,6 +1006,7 @@ where
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, T, E> IntoDeserializer<'de, E> for Vec<T>
 where
     T: IntoDeserializer<'de, E>,
@@ -1012,6 +1020,7 @@ where
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, T, E> IntoDeserializer<'de, E> for BTreeSet<T>
 where
     T: IntoDeserializer<'de, E> + Eq + Ord,
@@ -1025,6 +1034,7 @@ where
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<'de, T, S, E> IntoDeserializer<'de, E> for HashSet<T, S>
 where
     T: IntoDeserializer<'de, E> + Eq + Hash,
@@ -1411,6 +1421,7 @@ impl Expected for ExpectedInMap {
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, K, V, E> IntoDeserializer<'de, E> for BTreeMap<K, V>
 where
     K: IntoDeserializer<'de, E> + Eq + Ord,
@@ -1425,6 +1436,7 @@ where
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<'de, K, V, S, E> IntoDeserializer<'de, E> for HashMap<K, V, S>
 where
     K: IntoDeserializer<'de, E> + Eq + Hash,
diff --git a/serde/src/ser/impls.rs b/serde/src/ser/impls.rs
index fdf3994d7..8c70634af 100644
--- a/serde/src/ser/impls.rs
+++ b/serde/src/ser/impls.rs
@@ -48,6 +48,7 @@ impl Serialize for str {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl Serialize for String {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -70,6 +71,7 @@ impl<'a> Serialize for fmt::Arguments<'a> {
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(any(feature = "std", not(no_core_cstr)))]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for CStr {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -81,6 +83,7 @@ impl Serialize for CStr {
 }
 
 #[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
+#[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl Serialize for CString {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -226,31 +229,37 @@ macro_rules! seq_impl {
 
 seq_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     BinaryHeap<T: Ord>
 }
 
 seq_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     BTreeSet<T: Ord>
 }
 
 seq_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     HashSet<T: Eq + Hash, H: BuildHasher>
 }
 
 seq_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     LinkedList<T>
 }
 
 seq_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     Vec<T>
 }
 
 seq_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     VecDeque<T>
 }
 
@@ -359,6 +368,7 @@ impl Serialize for () {
 }
 
 #[cfg(feature = "unstable")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "unstable")))]
 impl Serialize for ! {
     fn serialize<S>(&self, _serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -463,11 +473,13 @@ macro_rules! map_impl {
 
 map_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     BTreeMap<K: Ord, V>
 }
 
 map_impl! {
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     HashMap<K: Eq + Hash, V, H: BuildHasher>
 }
 
@@ -501,6 +513,7 @@ deref_impl! {
 
 deref_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     <T: ?Sized> Serialize for Box<T> where T: Serialize
 }
 
@@ -514,6 +527,7 @@ deref_impl! {
     ///
     /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
     #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))))]
     <T: ?Sized> Serialize for Rc<T> where T: Serialize
 }
 
@@ -527,11 +541,13 @@ deref_impl! {
     ///
     /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
     #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))))]
     <T: ?Sized> Serialize for Arc<T> where T: Serialize
 }
 
 deref_impl! {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "std", feature = "alloc"))))]
     <'a, T: ?Sized> Serialize for Cow<'a, T> where T: Serialize + ToOwned
 }
 
@@ -541,6 +557,10 @@ deref_impl! {
 ///
 /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
 #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
+#[cfg_attr(
+    doc_cfg,
+    doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc"))))
+)]
 impl<T: ?Sized> Serialize for RcWeak<T>
 where
     T: Serialize,
@@ -557,6 +577,10 @@ where
 ///
 /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
 #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
+#[cfg_attr(
+    doc_cfg,
+    doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc"))))
+)]
 impl<T: ?Sized> Serialize for ArcWeak<T>
 where
     T: Serialize,
@@ -633,6 +657,7 @@ where
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<T: ?Sized> Serialize for Mutex<T>
 where
     T: Serialize,
@@ -649,6 +674,7 @@ where
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl<T: ?Sized> Serialize for RwLock<T>
 where
     T: Serialize,
@@ -702,6 +728,7 @@ impl Serialize for Duration {
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for SystemTime {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -746,6 +773,7 @@ macro_rules! serialize_display_bounded_length {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for net::IpAddr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -816,6 +844,7 @@ fn test_format_u8() {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for net::Ipv4Addr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -840,6 +869,7 @@ impl Serialize for net::Ipv4Addr {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for net::Ipv6Addr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -856,6 +886,7 @@ impl Serialize for net::Ipv6Addr {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for net::SocketAddr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -880,6 +911,7 @@ impl Serialize for net::SocketAddr {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for net::SocketAddrV4 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -896,6 +928,7 @@ impl Serialize for net::SocketAddrV4 {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for net::SocketAddrV6 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -917,6 +950,7 @@ impl Serialize for net::SocketAddrV6 {
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for Path {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -930,6 +964,7 @@ impl Serialize for Path {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl Serialize for PathBuf {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -940,6 +975,7 @@ impl Serialize for PathBuf {
 }
 
 #[cfg(all(feature = "std", any(unix, windows)))]
+#[cfg_attr(doc_cfg, doc(cfg(all(feature = "std", any(unix, windows)))))]
 impl Serialize for OsStr {
     #[cfg(unix)]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -962,6 +998,7 @@ impl Serialize for OsStr {
 }
 
 #[cfg(all(feature = "std", any(unix, windows)))]
+#[cfg_attr(doc_cfg, doc(cfg(all(feature = "std", any(unix, windows)))))]
 impl Serialize for OsString {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -1006,6 +1043,7 @@ macro_rules! atomic_impl {
     ($($ty:ident $size:expr)*) => {
         $(
             #[cfg(any(no_target_has_atomic, target_has_atomic = $size))]
+            #[cfg_attr(doc_cfg, doc(cfg(all(feature = "std", target_has_atomic = $size))))]
             impl Serialize for $ty {
                 fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
                 where