Reintroduce deprecated collections crate

src/bootstrap/dist.rs

@@ -550,6 +550,7 @@ pub fn rust_src(build: &Build) {
         "src/liballoc_jemalloc",
         "src/liballoc_system",
         "src/libbacktrace",
+        "src/libcollections",
         "src/libcompiler_builtins",
         "src/libcore",
         "src/liblibc",

src/bootstrap/doc.rs

@@ -254,7 +254,7 @@ pub fn std(build: &Build, stage: u32, target: &str) {
     // for which docs must be built.
     if !build.config.compiler_docs {
         cargo.arg("--no-deps");
-        for krate in &["alloc", "core", "std", "std_unicode"] {
+        for krate in &["alloc", "collections", "core", "std", "std_unicode"] {
             cargo.arg("-p").arg(krate);
             // Create all crate output directories first to make sure rustdoc uses
             // relative links.

src/doc/unstable-book/src/SUMMARY.md

@@ -108,6 +108,7 @@
     - [char_escape_debug](library-features/char-escape-debug.md)
     - [coerce_unsized](library-features/coerce-unsized.md)
     - [collection_placement](library-features/collection-placement.md)
+    - [collections](library-features/collections.md)
     - [collections_range](library-features/collections-range.md)
     - [command_envs](library-features/command-envs.md)
     - [compiler_builtins_lib](library-features/compiler-builtins-lib.md)

src/doc/unstable-book/src/library-features/collections.md

@@ -0,0 +1,5 @@
+# `collections`
+
+This feature is internal to the Rust compiler and is not intended for general use.
+
+------------------------

src/libcollections/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+authors = ["The Rust Project Developers"]
+name = "collections"
+version = "0.0.0"
+
+[lib]
+name = "collections"
+path = "lib.rs"
+
+[dependencies]
+alloc = { path = "../liballoc" }
+core = { path = "../libcore" }

src/libcollections/lib.rs

@@ -0,0 +1,72 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![crate_name = "collections"]
+#![crate_type = "rlib"]
+#![allow(unused_attributes)]
+#![unstable(feature = "collections",
+            reason = "this library is unlikely to be stabilized in its current \
+                      form or name",
+            issue = "27783")]
+#![rustc_deprecated(since = "1.20.0",
+                    reason = "collections moved to `alloc`")]
+#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
+       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
+       html_root_url = "https://doc.rust-lang.org/nightly/",
+       issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
+       test(no_crate_inject, attr(allow(unused_variables), deny(warnings))))]
+#![no_std]
+#![needs_allocator]
+#![deny(warnings)]
+
+#![feature(alloc)]
+#![feature(collections_range)]
+#![feature(macro_reexport)]
+#![feature(needs_allocator)]
+#![feature(staged_api)]
+
+//! Collection types
+//!
+//! See [`std::collections`](../std/collections/index.html) for a detailed
+//! discussion of collections in Rust.
+
+#[macro_reexport(vec, format)]
+extern crate alloc;
+
+pub use alloc::Bound;
+
+pub use alloc::binary_heap;
+pub use alloc::borrow;
+pub use alloc::fmt;
+pub use alloc::linked_list;
+pub use alloc::range;
+pub use alloc::slice;
+pub use alloc::str;
+pub use alloc::string;
+pub use alloc::vec;
+pub use alloc::vec_deque;
+
+pub use alloc::btree_map;
+pub use alloc::btree_set;
+
+#[doc(no_inline)]
+pub use alloc::binary_heap::BinaryHeap;
+#[doc(no_inline)]
+pub use alloc::btree_map::BTreeMap;
+#[doc(no_inline)]
+pub use alloc::btree_set::BTreeSet;
+#[doc(no_inline)]
+pub use alloc::linked_list::LinkedList;
+#[doc(no_inline)]
+pub use alloc::vec_deque::VecDeque;
+#[doc(no_inline)]
+pub use alloc::string::String;
+#[doc(no_inline)]
+pub use alloc::vec::Vec;

src/libstd/Cargo.toml

@@ -15,6 +15,7 @@ alloc_jemalloc = { path = "../liballoc_jemalloc", optional = true }
 alloc_system = { path = "../liballoc_system" }
 panic_unwind = { path = "../libpanic_unwind", optional = true }
 panic_abort = { path = "../libpanic_abort" }
+collections = { path = "../libcollections" }
 core = { path = "../libcore" }
 libc = { path = "../rustc/libc_shim" }
 rand = { path = "../librand" }