Rename doc_cfg to docsrs and use doc_auto_cfg (#1450)

Author: newpavlov

Cargo.toml

@@ -19,9 +19,9 @@ include = ["src/", "LICENSE-*", "README.md", "CHANGELOG.md", "COPYRIGHT"]
 
 [package.metadata.docs.rs]
 # To build locally:
-# RUSTDOCFLAGS="--cfg doc_cfg -Zunstable-options --generate-link-to-definition" cargo +nightly doc --all --all-features --no-deps --open
+# RUSTDOCFLAGS="--cfg docsrs -Zunstable-options --generate-link-to-definition" cargo +nightly doc --all --all-features --no-deps --open
 all-features = true
-rustdoc-args = ["--cfg", "doc_cfg", "-Zunstable-options", "--generate-link-to-definition"]
+rustdoc-args = ["--cfg", "docsrs", "--generate-link-to-definition"]
 
 [package.metadata.playground]
 features = ["small_rng", "serde1"]

rand_core/Cargo.toml

@@ -17,9 +17,9 @@ rust-version = "1.61"
 
 [package.metadata.docs.rs]
 # To build locally:
-# RUSTDOCFLAGS="--cfg doc_cfg" cargo +nightly doc --all-features --no-deps --open
+# RUSTDOCFLAGS="--cfg docsrs" cargo +nightly doc --all-features --no-deps --open
 all-features = true
-rustdoc-args = ["--cfg", "doc_cfg", "--generate-link-to-definition"]
+rustdoc-args = ["--cfg", "docsrs", "--generate-link-to-definition"]
 
 [package.metadata.playground]
 all-features = true

rand_core/src/blanket_impls.rs

@@ -44,7 +44,6 @@ impl<'a, R: TryRngCore + ?Sized> TryRngCore for &'a mut R {
 impl<'a, R: TryCryptoRng + ?Sized> TryCryptoRng for &'a mut R {}
 
 #[cfg(feature = "alloc")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 impl<R: RngCore + ?Sized> RngCore for Box<R> {
     #[inline(always)]
     fn next_u32(&mut self) -> u32 {
@@ -63,11 +62,9 @@ impl<R: RngCore + ?Sized> RngCore for Box<R> {
 }
 
 #[cfg(feature = "alloc")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 impl<R: CryptoRng + ?Sized> CryptoRng for Box<R> {}
 
 #[cfg(feature = "alloc")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 impl<R: TryRngCore + ?Sized> TryRngCore for Box<R> {
     type Error = R::Error;
 
@@ -88,5 +85,4 @@ impl<R: TryRngCore + ?Sized> TryRngCore for Box<R> {
 }
 
 #[cfg(feature = "alloc")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 impl<R: TryCryptoRng + ?Sized> TryCryptoRng for Box<R> {}

rand_core/src/impls.rs

@@ -160,7 +160,7 @@ pub fn next_u64_via_fill<R: RngCore + ?Sized>(rng: &mut R) -> u64 {
     u64::from_le_bytes(buf)
 }
 
-/// Implement [`TryRngCore`] for a type implementing [`RngCore`].
+/// Implement [`TryRngCore`][crate::TryRngCore] for a type implementing [`RngCore`].
 ///
 /// Ideally, `rand_core` would define blanket impls for this, but they conflict with blanket impls
 /// for `&mut R` and `Box<R>`, so until specialziation is stabilized, implementer crates
@@ -195,6 +195,10 @@ macro_rules! impl_try_rng_from_rng_core {
 /// Ideally, `rand_core` would define blanket impls for this, but they conflict with blanket impls
 /// for `&mut R` and `Box<R>`, so until specialziation is stabilized, implementer crates
 /// have to implement `TryRngCore` and `TryCryptoRng` directly.
+///
+/// [`TryCryptoRng`]: crate::TryCryptoRng
+/// [`TryRngCore`]: crate::TryRngCore
+/// [`CryptoRng`]: crate::CryptoRng
 #[macro_export]
 macro_rules! impl_try_crypto_rng_from_crypto_rng {
     ($t:ty) => {

rand_core/src/lib.rs

@@ -32,8 +32,7 @@
 #![deny(missing_docs)]
 #![deny(missing_debug_implementations)]
 #![doc(test(attr(allow(unused_variables), deny(warnings))))]
-#![allow(unexpected_cfgs)]
-#![cfg_attr(doc_cfg, feature(doc_cfg))]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #![no_std]
 
 #[cfg(feature = "alloc")]
@@ -446,7 +445,6 @@ pub trait SeedableRng: Sized {
     /// [`getrandom`]: https://docs.rs/getrandom
     /// [`try_from_os_rng`]: SeedableRng::try_from_os_rng
     #[cfg(feature = "getrandom")]
-    #[cfg_attr(doc_cfg, doc(cfg(feature = "getrandom")))]
     fn from_os_rng() -> Self {
         match Self::try_from_os_rng() {
             Ok(res) => res,
@@ -463,7 +461,6 @@ pub trait SeedableRng: Sized {
     ///
     /// [`getrandom`]: https://docs.rs/getrandom
     #[cfg(feature = "getrandom")]
-    #[cfg_attr(doc_cfg, doc(cfg(feature = "getrandom")))]
     fn try_from_os_rng() -> Result<Self, getrandom::Error> {
         let mut seed = Self::Seed::default();
         getrandom::getrandom(seed.as_mut())?;

rand_core/src/os.rs

@@ -44,7 +44,6 @@ use getrandom::getrandom;
 /// ```
 ///
 /// [getrandom]: https://crates.io/crates/getrandom
-#[cfg_attr(doc_cfg, doc(cfg(feature = "getrandom")))]
 #[derive(Clone, Copy, Debug, Default)]
 pub struct OsRng;
 

rand_distr/Cargo.toml

@@ -17,7 +17,7 @@ rust-version = "1.61"
 include = ["src/", "LICENSE-*", "README.md", "CHANGELOG.md", "COPYRIGHT"]
 
 [package.metadata.docs.rs]
-rustdoc-args = ["--generate-link-to-definition"]
+rustdoc-args = ["--cfg docsrs", "--generate-link-to-definition"]
 
 [features]
 default = ["std"]

rand_distr/src/binomial.rs

@@ -58,7 +58,6 @@ impl fmt::Display for Error {
 }
 
 #[cfg(feature = "std")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl std::error::Error for Error {}
 
 impl Binomial {

rand_distr/src/cauchy.rs

@@ -58,7 +58,6 @@ impl fmt::Display for Error {
 }
 
 #[cfg(feature = "std")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl std::error::Error for Error {}
 
 impl<F> Cauchy<F>

rand_distr/src/dirichlet.rs

@@ -31,7 +31,6 @@ where
 }
 
 /// Error type returned from `DirchletFromGamma::new`.
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 enum DirichletFromGammaError {
     /// Gamma::new(a, 1) failed.
@@ -104,7 +103,6 @@ where
 }
 
 /// Error type returned from `DirchletFromBeta::new`.
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 enum DirichletFromBetaError {
     /// Beta::new(a, b) failed.
@@ -203,7 +201,6 @@ where
 /// let samples = dirichlet.sample(&mut rand::thread_rng());
 /// println!("{:?} is from a Dirichlet([1.0, 2.0, 3.0]) distribution", samples);
 /// ```
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 #[cfg_attr(feature = "serde_with", serde_as)]
 #[derive(Clone, Debug, PartialEq)]
 pub struct Dirichlet<F, const N: usize>
@@ -217,7 +214,6 @@ where
 }
 
 /// Error type returned from `Dirchlet::new`.
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum Error {
     /// `alpha.len() < 2`.
@@ -257,7 +253,6 @@ impl fmt::Display for Error {
 }
 
 #[cfg(feature = "std")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 impl std::error::Error for Error {}
 
 impl<F, const N: usize> Dirichlet<F, N>