diff --git a/serde/build.rs b/serde/build.rs index 82129bc72..e27e2f34f 100644 --- a/serde/build.rs +++ b/serde/build.rs @@ -23,6 +23,12 @@ fn main() { println!("cargo:rustc-cfg=collections_bound"); } + // core::cmp::Reverse stabilized in Rust 1.19: + // https://doc.rust-lang.org/stable/core/cmp/struct.Reverse.html + if minor >= 19 { + println!("cargo:rustc-cfg=core_reverse"); + } + // CString::into_boxed_c_str stabilized in Rust 1.20: // https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str if minor >= 20 { diff --git a/serde/src/de/impls.rs b/serde/src/de/impls.rs index 13c8b5a7c..1c18fd969 100644 --- a/serde/src/de/impls.rs +++ b/serde/src/de/impls.rs @@ -578,6 +578,9 @@ macro_rules! forwarded_impl { #[cfg(all(feature = "std", de_boxed_c_str))] forwarded_impl!((), Box, CString::into_boxed_c_str); +#[cfg(core_reverse)] +forwarded_impl!((T), Reverse, Reverse); + //////////////////////////////////////////////////////////////////////////////// struct OptionVisitor { diff --git a/serde/src/lib.rs b/serde/src/lib.rs index 1d953d846..17d07dc3f 100644 --- a/serde/src/lib.rs +++ b/serde/src/lib.rs @@ -139,6 +139,8 @@ mod lib { pub use self::core::cell::{Cell, RefCell}; pub use self::core::clone::{self, Clone}; + #[cfg(core_reverse)] + pub use self::core::cmp::Reverse; pub use self::core::convert::{self, From, Into}; pub use self::core::default::{self, Default}; pub use self::core::fmt::{self, Debug, Display}; diff --git a/serde/src/ser/impls.rs b/serde/src/ser/impls.rs index 8b40bda31..46d406b23 100644 --- a/serde/src/ser/impls.rs +++ b/serde/src/ser/impls.rs @@ -824,3 +824,17 @@ where self.0.serialize(serializer) } } + +#[cfg(core_reverse)] +impl Serialize for Reverse + where + T: Serialize, +{ + #[inline] + fn serialize(&self, serializer: S) -> Result + where + S: Serializer, + { + self.0.serialize(serializer) + } +}