Stabilize the alloc crate.

This implements RFC 2480:

* https://github.com/rust-lang/rfcs/pull/2480
* https://github.com/rust-lang/rfcs/blob/master/text/2480-liballoc.md

Closes https://github.com/rust-lang/rust/issues/27783

src/liballoc/lib.rs

@@ -51,10 +51,7 @@
 //! default global allocator. It is not compatible with the libc allocator API.
 
 #![allow(unused_attributes)]
-#![unstable(feature = "alloc",
-            reason = "this library is unlikely to be stabilized in its current \
-                      form or name",
-            issue = "27783")]
+#![stable(feature = "alloc", since = "1.36.0")]
 #![doc(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))))]

src/liballoc/prelude/mod.rs

@@ -5,7 +5,6 @@
 //!
 //! ```
 //! # #![allow(unused_imports)]
-//! # #![feature(alloc)]
 //! #![feature(alloc_prelude)]
 //! extern crate alloc;
 //! use alloc::prelude::v1::*;

src/liballoc/raw_vec.rs

@@ -256,7 +256,7 @@ impl<T, A: Alloc> RawVec<T, A> {
     /// # Examples
     ///
     /// ```
-    /// # #![feature(alloc, raw_vec_internals)]
+    /// # #![feature(raw_vec_internals)]
     /// # extern crate alloc;
     /// # use std::ptr;
     /// # use alloc::raw_vec::RawVec;
@@ -460,7 +460,7 @@ impl<T, A: Alloc> RawVec<T, A> {
     /// # Examples
     ///
     /// ```
-    /// # #![feature(alloc, raw_vec_internals)]
+    /// # #![feature(raw_vec_internals)]
     /// # extern crate alloc;
     /// # use std::ptr;
     /// # use alloc::raw_vec::RawVec;

src/libarena/lib.rs

@@ -13,7 +13,6 @@
 
 #![deny(rust_2018_idioms)]
 
-#![feature(alloc)]
 #![feature(core_intrinsics)]
 #![feature(dropck_eyepatch)]
 #![feature(raw_vec_internals)]

src/libpanic_unwind/lib.rs

@@ -19,8 +19,6 @@
 
 #![deny(rust_2018_idioms)]
 
-#![feature(allocator_api)]
-#![feature(alloc)]
 #![feature(core_intrinsics)]
 #![feature(lang_items)]
 #![feature(libc)]

src/libstd/lib.rs

@@ -229,7 +229,6 @@
 #![feature(align_offset)]
 #![feature(alloc_error_handler)]
 #![feature(alloc_layout_extra)]
-#![feature(alloc)]
 #![feature(allocator_api)]
 #![feature(allocator_internals)]
 #![feature(allow_internal_unsafe)]

src/test/run-make-fulldeps/sysroot-crates-are-unstable/test.py

@@ -7,8 +7,8 @@ from subprocess import PIPE, Popen
 
 # This is a whitelist of files which are stable crates or simply are not crates,
 # we don't check for the instability of these crates as they're all stable!
-STABLE_CRATES = ['std', 'core', 'proc_macro', 'rsbegin.o', 'rsend.o', 'dllcrt2.o', 'crt2.o',
-                 'clang_rt']
+STABLE_CRATES = ['std', 'alloc', 'core', 'proc_macro',
+                 'rsbegin.o', 'rsend.o', 'dllcrt2.o', 'crt2.o', 'clang_rt']
 
 
 def convert_to_string(s):

src/test/run-pass/array-slice-vec/vec-macro-no-std.rs

@@ -2,7 +2,7 @@
 
 // ignore-emscripten no no_std executables
 
-#![feature(lang_items, start, rustc_private, alloc)]
+#![feature(lang_items, start, rustc_private)]
 #![no_std]
 
 extern crate std as other;

src/test/run-pass/extern/extern-prelude-core.rs

@@ -1,5 +1,5 @@
 // run-pass
-#![feature(extern_prelude, lang_items, start, alloc)]
+#![feature(extern_prelude, lang_items, start)]
 #![no_std]
 
 extern crate std as other;

src/test/run-pass/extern/extern-prelude-core.stderr

@@ -1,7 +1,7 @@
 warning: the feature `extern_prelude` has been stable since 1.30.0 and no longer requires an attribute to enable
   --> $DIR/extern-prelude-core.rs:2:12
    |
-LL | #![feature(extern_prelude, lang_items, start, alloc)]
+LL | #![feature(extern_prelude, lang_items, start)]
    |            ^^^^^^^^^^^^^^
    |
    = note: #[warn(stable_features)] on by default

src/test/run-pass/for-loop-while/for-loop-no-std.rs

@@ -1,6 +1,6 @@
 // run-pass
 #![allow(unused_imports)]
-#![feature(lang_items, start, alloc)]
+#![feature(lang_items, start)]
 #![no_std]
 
 extern crate std as other;

src/test/run-pass/format-no-std.rs

@@ -1,6 +1,6 @@
 // ignore-emscripten no no_std executables
 
-#![feature(lang_items, start, alloc)]
+#![feature(lang_items, start)]
 #![no_std]
 
 extern crate std as other;

src/test/run-pass/structs-enums/unit-like-struct-drop-run.rs

@@ -3,9 +3,6 @@
 
 // Make sure the destructor is run for unit-like structs.
 
-
-#![feature(alloc)]
-
 use std::thread;
 
 struct Foo;

src/test/ui/allocator-submodule.rs

@@ -1,8 +1,6 @@
 // Tests that it is possible to create a global allocator in a submodule, rather than in the crate
 // root.
 
-#![feature(alloc, allocator_api, global_allocator)]
-
 extern crate alloc;
 
 use std::{

src/test/ui/allocator-submodule.stderr

@@ -1,5 +1,5 @@
 error: `global_allocator` cannot be used in submodules
-  --> $DIR/allocator-submodule.rs:27:5
+  --> $DIR/allocator-submodule.rs:25:5
    |
 LL |     static MY_HEAP: MyAlloc = MyAlloc;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/test/ui/error-codes/E0254.rs

@@ -1,4 +1,3 @@
-#![feature(alloc)]
 #![allow(unused_extern_crates, non_camel_case_types)]
 
 extern crate alloc;

src/test/ui/error-codes/E0254.stderr

@@ -1,5 +1,5 @@
 error[E0254]: the name `alloc` is defined multiple times
-  --> $DIR/E0254.rs:12:5
+  --> $DIR/E0254.rs:11:5
    |
 LL | extern crate alloc;
    | ------------------- previous import of the extern crate `alloc` here

src/test/ui/error-codes/E0259.rs

@@ -1,4 +1,4 @@
-#![feature(alloc, rustc_private)]
+#![feature(rustc_private)]
 #![allow(unused_extern_crates)]
 
 extern crate alloc;

src/test/ui/error-codes/E0260.rs

@@ -1,4 +1,3 @@
-#![feature(alloc)]
 #![allow(unused_extern_crates)]
 
 extern crate alloc;

src/test/ui/error-codes/E0260.stderr

@@ -1,5 +1,5 @@
 error[E0260]: the name `alloc` is defined multiple times
-  --> $DIR/E0260.rs:6:1
+  --> $DIR/E0260.rs:5:1
    |
 LL | extern crate alloc;
    | ------------------- previous import of the extern crate `alloc` here

src/test/ui/missing/missing-alloc_error_handler.rs

@@ -3,7 +3,7 @@
 
 #![no_std]
 #![crate_type = "staticlib"]
-#![feature(panic_handler, alloc_error_handler, alloc)]
+#![feature(panic_handler, alloc_error_handler)]
 
 #[panic_handler]
 fn panic(_: &core::panic::PanicInfo) -> ! {

src/test/ui/missing/missing-allocator.rs

@@ -3,7 +3,7 @@
 
 #![no_std]
 #![crate_type = "staticlib"]
-#![feature(panic_handler, alloc_error_handler, alloc)]
+#![feature(panic_handler, alloc_error_handler)]
 
 #[panic_handler]
 fn panic(_: &core::panic::PanicInfo) -> ! {

src/test/ui/resolve_self_super_hint.rs

@@ -1,4 +1,3 @@
-#![feature(alloc)]
 #![allow(unused_extern_crates)]
 
 mod a {

src/test/ui/resolve_self_super_hint.stderr

@@ -1,17 +1,17 @@
 error[E0432]: unresolved import `alloc`
-  --> $DIR/resolve_self_super_hint.rs:6:9
+  --> $DIR/resolve_self_super_hint.rs:5:9
    |
 LL |     use alloc::HashMap;
    |         ^^^^^ help: a similar path exists: `self::alloc`
 
 error[E0432]: unresolved import `alloc`
-  --> $DIR/resolve_self_super_hint.rs:11:13
+  --> $DIR/resolve_self_super_hint.rs:10:13
    |
 LL |         use alloc::HashMap;
    |             ^^^^^ help: a similar path exists: `super::alloc`
 
 error[E0432]: unresolved import `alloc`
-  --> $DIR/resolve_self_super_hint.rs:16:17
+  --> $DIR/resolve_self_super_hint.rs:15:17
    |
 LL |             use alloc::HashMap;
    |                 ^^^^^
@@ -20,7 +20,7 @@ LL |             use alloc::HashMap;
    |                 help: a similar path exists: `a::alloc`
 
 error[E0432]: unresolved import `alloc`
-  --> $DIR/resolve_self_super_hint.rs:21:21
+  --> $DIR/resolve_self_super_hint.rs:20:21
    |
 LL |                 use alloc::HashMap;
    |                     ^^^^^

src/test/ui/rust-2018/remove-extern-crate.fixed

@@ -4,7 +4,6 @@
 // aux-build:remove-extern-crate.rs
 // compile-flags:--extern remove_extern_crate
 
-#![feature(alloc)]
 #![warn(rust_2018_idioms)]
 
 

src/test/ui/rust-2018/remove-extern-crate.rs

@@ -4,7 +4,6 @@
 // aux-build:remove-extern-crate.rs
 // compile-flags:--extern remove_extern_crate
 
-#![feature(alloc)]
 #![warn(rust_2018_idioms)]
 
 extern crate core;

src/test/ui/rust-2018/remove-extern-crate.stderr

@@ -1,24 +1,24 @@
 warning: unused extern crate
-  --> $DIR/remove-extern-crate.rs:10:1
+  --> $DIR/remove-extern-crate.rs:9:1
    |
 LL | extern crate core;
    | ^^^^^^^^^^^^^^^^^^ help: remove it
    |
 note: lint level defined here
-  --> $DIR/remove-extern-crate.rs:8:9
+  --> $DIR/remove-extern-crate.rs:7:9
    |
 LL | #![warn(rust_2018_idioms)]
    |         ^^^^^^^^^^^^^^^^
    = note: #[warn(unused_extern_crates)] implied by #[warn(rust_2018_idioms)]
 
 warning: `extern crate` is not idiomatic in the new edition
-  --> $DIR/remove-extern-crate.rs:11:1
+  --> $DIR/remove-extern-crate.rs:10:1
    |
 LL | extern crate core as another_name;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `use`
 
 warning: `extern crate` is not idiomatic in the new edition
-  --> $DIR/remove-extern-crate.rs:29:5
+  --> $DIR/remove-extern-crate.rs:28:5
    |
 LL |     extern crate core;
    |     ^^^^^^^^^^^^^^^^^^ help: convert it to a `use`

src/test/ui/unnecessary-extern-crate.rs

@@ -1,7 +1,7 @@
 // edition:2018
 
 #![deny(unused_extern_crates)]
-#![feature(alloc, test, rustc_private, crate_visibility_modifier)]
+#![feature(test, rustc_private, crate_visibility_modifier)]
 
 extern crate libc;
 //~^ ERROR unused extern crate