Auto merge of #55660 - alexcrichton:cleanup-alloc-system, r=dtolnay,SimonSapin

Remove the `alloc_system` crate

In what's hopefully one of the final nails in the coffin of the "old allocator story of yore" this PR deletes the `alloc_system` crate and all traces of it from the compiler. The compiler no longer needs to inject allocator crates anywhere and the `alloc_system` crate has no real reason to exist outside the standard library.

The unstable `alloc_system` crate is folded directly into the standard library where its stable interface, the `System` type, remains the same. All unstable traces of `alloc_system` are removed, however.

2 files changed, 1 insertions, 4 deletions

diff --git a/src/liballoc/tests/heap.rs b/src/liballoc/tests/heap.rs
index b6be38107da..bf256b23f9a 100644
--- a/src/liballoc/tests/heap.rs
+++ b/src/liballoc/tests/heap.rs
@@ -8,8 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use alloc_system::System;
-use std::alloc::{Global, Alloc, Layout};
+use std::alloc::{Global, Alloc, Layout, System};
 
 /// https://github.com/rust-lang/rust/issues/45955
 #[test]
diff --git a/src/liballoc/tests/lib.rs b/src/liballoc/tests/lib.rs
index 3294837cb91..e514a8a69c0 100644
--- a/src/liballoc/tests/lib.rs
+++ b/src/liballoc/tests/lib.rs
@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![feature(allocator_api)]
-#![feature(alloc_system)]
 #![feature(box_syntax)]
 #![feature(drain_filter)]
 #![feature(exact_size_is_empty)]
@@ -20,7 +19,6 @@
 #![feature(unboxed_closures)]
 #![feature(repeat_generic_slice)]
 
-extern crate alloc_system;
 extern crate core;
 extern crate rand;