Auto merge of #55912 - kennytm:rollup, r=kennytm

Rollup of 20 pull requests

Successful merges:

 - #55136 (Remove short doc where it starts with a codeblock)
 - #55711 (Format BtreeMap::range_mut example)
 - #55722 (impl_stable_hash_for: support enums and tuple structs with generic parameters)
 - #55754 (Avoid converting bytes to UTF-8 strings to print, just pass bytes to stdout/err)
 - #55804 (rustdoc: don't inline `pub use some_crate` unless directly asked to)
 - #55805 (Move `static_assert!` into librustc_data_structures)
 - #55837 (Make PhantomData #[structural_match])
 - #55840 (Fix TLS errors when downloading stage0)
 - #55843 (add FromIterator<A> to Box<[A]>)
 - #55858 (Small fixes on code blocks in rustdoc)
 - #55863 (Fix a typo in std::panic)
 - #55870 (Fix typos.)
 - #55874 (string: Add documentation for `From` impls)
 - #55879 (save-analysis: Don't panic for macro-generated use globs)
 - #55882 (Reference count `crate_inherent_impls`s return value.)
 - #55888 (miri: for uniformity, also move memory_deallocated to AllocationExtra)
 - #55889 (global allocators: add a few comments)
 - #55896 (Document optimizations enabled by FusedIterator)
 - #55905 (Change `Lit::short_name` to `Lit::literal_name`.)
 - #55908 (Fix their/there grammar nit)

1 files changed, 5 insertions, 0 deletions

diff --git a/src/libstd/alloc.rs b/src/libstd/alloc.rs
index 485b2ffe197..9c057396470 100644
--- a/src/libstd/alloc.rs
+++ b/src/libstd/alloc.rs
@@ -142,6 +142,7 @@ pub use alloc_crate::alloc::*;
 #[derive(Debug, Copy, Clone)]
 pub struct System;
 
+// The Alloc impl just forwards to the GlobalAlloc impl, which is in `std::sys::*::alloc`.
 #[unstable(feature = "allocator_api", issue = "32838")]
 unsafe impl Alloc for System {
     #[inline]
@@ -226,6 +227,10 @@ pub fn rust_oom(layout: Layout) -> ! {
 #[unstable(feature = "alloc_internals", issue = "0")]
 pub mod __default_lib_allocator {
     use super::{System, Layout, GlobalAlloc};
+    // These magic symbol names are used as a fallback for implementing the
+    // `__rust_alloc` etc symbols (see `src/liballoc/alloc.rs) when there is
+    // no `#[global_allocator]` attribute.
+
     // for symbol names src/librustc/middle/allocator.rs
     // for signatures src/librustc_allocator/lib.rs