Automatically document feature flag requirements on docs.rs by using the feature doc_auto_cfg

Cargo.toml

@@ -54,7 +54,11 @@ debug = true
 debug = true
 
 [package.metadata.docs.rs]
-features = ["borsh", "serde", "zeroize"]
+all-features = true
+# Enables the `docsrs` config attribute when running on docs.rs,
+# which always uses the latest nightly compiler. 
+# Idea taken from <https://stackoverflow.com/a/70914430>.
+rustdoc-flags = ["--cfg", "docsrs"]
 
 [package.metadata.release]
 no-dev-version = true

src/array_string.rs

@@ -580,7 +580,6 @@ impl<const CAP: usize> FromStr for ArrayString<CAP>
 }
 
 #[cfg(feature="serde")]
-/// Requires crate feature `"serde"`
 impl<const CAP: usize> Serialize for ArrayString<CAP>
 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -591,7 +590,6 @@ impl<const CAP: usize> Serialize for ArrayString<CAP>
 }
 
 #[cfg(feature="serde")]
-/// Requires crate feature `"serde"`
 impl<'de, const CAP: usize> Deserialize<'de> for ArrayString<CAP> 
 {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
@@ -629,15 +627,13 @@ impl<'de, const CAP: usize> Deserialize<'de> for ArrayString<CAP>
 }
 
 #[cfg(feature = "borsh")]
-/// Requires crate feature `"borsh"`
 impl<const CAP: usize> borsh::BorshSerialize for ArrayString<CAP> {
     fn serialize<W: borsh::io::Write>(&self, writer: &mut W) -> borsh::io::Result<()> {
         <str as borsh::BorshSerialize>::serialize(&*self, writer)
     }
 }
 
 #[cfg(feature = "borsh")]
-/// Requires crate feature `"borsh"`
 impl<const CAP: usize> borsh::BorshDeserialize for ArrayString<CAP> {
     fn deserialize_reader<R: borsh::io::Read>(reader: &mut R) -> borsh::io::Result<Self> {
         let len = <u32 as borsh::BorshDeserialize>::deserialize_reader(reader)? as usize;
@@ -683,7 +679,7 @@ impl<'a, const CAP: usize> TryFrom<fmt::Arguments<'a>> for ArrayString<CAP>
 }
 
 #[cfg(feature = "zeroize")]
-/// "Best efforts" zeroing of the `ArrayString`'s buffer when the `zeroize` feature is enabled.
+/// "Best efforts" zeroing of the `ArrayString`'s buffer.
 ///
 /// The length is set to 0, and the buffer is dropped and zeroized.
 /// Cannot ensure that previous moves of the `ArrayString` did not leave values on the stack.

src/arrayvec.rs

@@ -850,7 +850,7 @@ impl<T, const CAP: usize> IntoIterator for ArrayVec<T, CAP> {
 
 
 #[cfg(feature = "zeroize")]
-/// "Best efforts" zeroing of the `ArrayVec`'s buffer when the `zeroize` feature is enabled.
+/// "Best efforts" zeroing of the `ArrayVec`'s buffer.
 ///
 /// The length is set to 0, and the buffer is dropped and zeroized.
 /// Cannot ensure that previous moves of the `ArrayVec` did not leave values on the stack.
@@ -1254,8 +1254,6 @@ impl<T, const CAP: usize> Ord for ArrayVec<T, CAP> where T: Ord {
 
 #[cfg(feature="std")]
 /// `Write` appends written data to the end of the vector.
-///
-/// Requires `features="std"`.
 impl<const CAP: usize> io::Write for ArrayVec<u8, CAP> {
     fn write(&mut self, data: &[u8]) -> io::Result<usize> {
         let len = cmp::min(self.remaining_capacity(), data.len());
@@ -1267,7 +1265,6 @@ impl<const CAP: usize> io::Write for ArrayVec<u8, CAP> {
 }
 
 #[cfg(feature="serde")]
-/// Requires crate feature `"serde"`
 impl<T: Serialize, const CAP: usize> Serialize for ArrayVec<T, CAP> {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer
@@ -1277,7 +1274,6 @@ impl<T: Serialize, const CAP: usize> Serialize for ArrayVec<T, CAP> {
 }
 
 #[cfg(feature="serde")]
-/// Requires crate feature `"serde"`
 impl<'de, T: Deserialize<'de>, const CAP: usize> Deserialize<'de> for ArrayVec<T, CAP> {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer<'de>
@@ -1314,7 +1310,6 @@ impl<'de, T: Deserialize<'de>, const CAP: usize> Deserialize<'de> for ArrayVec<T
 }
 
 #[cfg(feature = "borsh")]
-/// Requires crate feature `"borsh"`
 impl<T, const CAP: usize> borsh::BorshSerialize for ArrayVec<T, CAP>
 where
     T: borsh::BorshSerialize,
@@ -1325,7 +1320,6 @@ where
 }
 
 #[cfg(feature = "borsh")]
-/// Requires crate feature `"borsh"`
 impl<T, const CAP: usize> borsh::BorshDeserialize for ArrayVec<T, CAP>
 where
     T: borsh::BorshDeserialize,

src/errors.rs

@@ -32,7 +32,6 @@ impl<T> CapacityError<T> {
 const CAPERROR: &'static str = "insufficient capacity";
 
 #[cfg(feature="std")]
-/// Requires `features="std"`.
 impl<T: Any> Error for CapacityError<T> {}
 
 impl<T> fmt::Display for CapacityError<T> {

src/lib.rs

@@ -21,6 +21,9 @@
 //!
 #![doc(html_root_url="https://docs.rs/arrayvec/0.7/")]
 #![cfg_attr(not(feature="std"), no_std)]
+// This enables the nightly feature `doc_auto_cfg` when running on docs.rs,
+// which always uses the nightly compiler.
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
 
 #[cfg(feature="serde")]
 extern crate serde;