From 1ab9fe5d44860050232438967bbbf9bdc35dbde1 Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Wed, 17 Feb 2021 13:33:47 +0100
Subject: [PATCH] Add {core,std}::prelude::{rust_2015,rust_2018,rust_2021}.

rust_2015 and rust_2018 are just re-exports of v1.
rust_2021 is a module that for now just re-exports everything from v1,
such that we can add more things later.
---
 library/core/src/prelude/mod.rs | 36 +++++++++++++++++++++++++++++++++
 library/core/src/prelude/v1.rs  |  6 ++----
 library/std/src/lib.rs          |  1 +
 library/std/src/prelude/mod.rs  | 34 +++++++++++++++++++++++++++++++
 4 files changed, 73 insertions(+), 4 deletions(-)

diff --git a/library/core/src/prelude/mod.rs b/library/core/src/prelude/mod.rs
index 51f4acf0685..1cb65eabb9a 100644
--- a/library/core/src/prelude/mod.rs
+++ b/library/core/src/prelude/mod.rs
@@ -1,5 +1,41 @@
 //! The libcore prelude
+//!
+//! This module is intended for users of libcore which do not link to libstd as
+//! well. This module is imported by default when `#![no_std]` is used in the
+//! same manner as the standard library's prelude.
 
 #![stable(feature = "core_prelude", since = "1.4.0")]
 
 pub mod v1;
+
+/// The 2015 version of the core prelude.
+///
+/// See the [module-level documentation](../index.html) for more.
+#[unstable(feature = "prelude_2015", issue = "none")]
+pub mod rust_2015 {
+    #[unstable(feature = "prelude_2015", issue = "none")]
+    #[doc(no_inline)]
+    pub use super::v1::*;
+}
+
+/// The 2018 version of the core prelude.
+///
+/// See the [module-level documentation](../index.html) for more.
+#[unstable(feature = "prelude_2018", issue = "none")]
+pub mod rust_2018 {
+    #[unstable(feature = "prelude_2018", issue = "none")]
+    #[doc(no_inline)]
+    pub use super::v1::*;
+}
+
+/// The 2021 version of the core prelude.
+///
+/// See the [module-level documentation](../index.html) for more.
+#[unstable(feature = "prelude_2021", issue = "none")]
+pub mod rust_2021 {
+    #[unstable(feature = "prelude_2021", issue = "none")]
+    #[doc(no_inline)]
+    pub use super::v1::*;
+
+    // FIXME: Add more things.
+}
diff --git a/library/core/src/prelude/v1.rs b/library/core/src/prelude/v1.rs
index a1fbd8dec75..993281fe882 100644
--- a/library/core/src/prelude/v1.rs
+++ b/library/core/src/prelude/v1.rs
@@ -1,8 +1,6 @@
-//! The core prelude
+//! The first version of the core prelude.
 //!
-//! This module is intended for users of libcore which do not link to libstd as
-//! well. This module is imported by default when `#![no_std]` is used in the
-//! same manner as the standard library's prelude.
+//! See the [module-level documentation](../index.html) for more.
 
 #![stable(feature = "core_prelude", since = "1.4.0")]
 
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 588bffb57c9..de816bdfef0 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -299,6 +299,7 @@
 #![feature(panic_internals)]
 #![feature(panic_unwind)]
 #![feature(pin_static_ref)]
+#![feature(prelude_2021)]
 #![feature(prelude_import)]
 #![feature(ptr_internals)]
 #![feature(raw)]
diff --git a/library/std/src/prelude/mod.rs b/library/std/src/prelude/mod.rs
index eb2095b8196..bb45aed90e7 100644
--- a/library/std/src/prelude/mod.rs
+++ b/library/std/src/prelude/mod.rs
@@ -84,3 +84,37 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 pub mod v1;
+
+/// The 2015 version of the prelude of The Rust Standard Library.
+///
+/// See the [module-level documentation](../index.html) for more.
+#[unstable(feature = "prelude_2015", issue = "none")]
+pub mod rust_2015 {
+    #[unstable(feature = "prelude_2015", issue = "none")]
+    #[doc(no_inline)]
+    pub use super::v1::*;
+}
+
+/// The 2018 version of the prelude of The Rust Standard Library.
+///
+/// See the [module-level documentation](../index.html) for more.
+#[unstable(feature = "prelude_2018", issue = "none")]
+pub mod rust_2018 {
+    #[unstable(feature = "prelude_2018", issue = "none")]
+    #[doc(no_inline)]
+    pub use super::v1::*;
+}
+
+/// The 2021 version of the prelude of The Rust Standard Library.
+///
+/// See the [module-level documentation](../index.html) for more.
+#[unstable(feature = "prelude_2021", issue = "none")]
+pub mod rust_2021 {
+    #[unstable(feature = "prelude_2021", issue = "none")]
+    #[doc(no_inline)]
+    pub use super::v1::*;
+
+    #[unstable(feature = "prelude_2021", issue = "none")]
+    #[doc(no_inline)]
+    pub use core::prelude::rust_2021::*;
+}