16 files changed, 60 insertions, 45 deletions

diff --git a/src/doc/unstable-book/src/library-features/allocator-api.md b/src/doc/unstable-book/src/library-features/allocator-api.md
index e3969ace7e9..9f045ce08a4 100644
--- a/src/doc/unstable-book/src/library-features/allocator-api.md
+++ b/src/doc/unstable-book/src/library-features/allocator-api.md
@@ -9,7 +9,7 @@ The tracking issue for this feature is [#32838]
 Sometimes you want the memory for one collection to use a different
 allocator than the memory for another collection. In this case,
 replacing the global allocator is not a workable option. Instead,
-you need to pass in an instance of an `Alloc` to each collection
+you need to pass in an instance of an `AllocRef` to each collection
 for which you want a custom allocator.
 
 TBD
diff --git a/src/liballoc/alloc.rs b/src/liballoc/alloc.rs
index 0c0dc928b95..9fb0de63e6f 100644
--- a/src/liballoc/alloc.rs
+++ b/src/liballoc/alloc.rs
@@ -31,14 +31,14 @@ extern "Rust" {
 
 /// The global memory allocator.
 ///
-/// This type implements the [`Alloc`] trait by forwarding calls
+/// This type implements the [`AllocRef`] trait by forwarding calls
 /// to the allocator registered with the `#[global_allocator]` attribute
 /// if there is one, or the `std` crate’s default.
 ///
 /// Note: while this type is unstable, the functionality it provides can be
 /// accessed through the [free functions in `alloc`](index.html#functions).
 ///
-/// [`Alloc`]: trait.Alloc.html
+/// [`AllocRef`]: trait.AllocRef.html
 #[unstable(feature = "allocator_api", issue = "32838")]
 #[derive(Copy, Clone, Default, Debug)]
 pub struct Global;
@@ -50,14 +50,14 @@ pub struct Global;
 /// if there is one, or the `std` crate’s default.
 ///
 /// This function is expected to be deprecated in favor of the `alloc` method
-/// of the [`Global`] type when it and the [`Alloc`] trait become stable.
+/// of the [`Global`] type when it and the [`AllocRef`] trait become stable.
 ///
 /// # Safety
 ///
 /// See [`GlobalAlloc::alloc`].
 ///
 /// [`Global`]: struct.Global.html
-/// [`Alloc`]: trait.Alloc.html
+/// [`AllocRef`]: trait.AllocRef.html
 /// [`GlobalAlloc::alloc`]: trait.GlobalAlloc.html#tymethod.alloc
 ///
 /// # Examples
@@ -88,14 +88,14 @@ pub unsafe fn alloc(layout: Layout) -> *mut u8 {
 /// if there is one, or the `std` crate’s default.
 ///
 /// This function is expected to be deprecated in favor of the `dealloc` method
-/// of the [`Global`] type when it and the [`Alloc`] trait become stable.
+/// of the [`Global`] type when it and the [`AllocRef`] trait become stable.
 ///
 /// # Safety
 ///
 /// See [`GlobalAlloc::dealloc`].
 ///
 /// [`Global`]: struct.Global.html
-/// [`Alloc`]: trait.Alloc.html
+/// [`AllocRef`]: trait.AllocRef.html
 /// [`GlobalAlloc::dealloc`]: trait.GlobalAlloc.html#tymethod.dealloc
 #[stable(feature = "global_alloc", since = "1.28.0")]
 #[inline]
@@ -110,14 +110,14 @@ pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
 /// if there is one, or the `std` crate’s default.
 ///
 /// This function is expected to be deprecated in favor of the `realloc` method
-/// of the [`Global`] type when it and the [`Alloc`] trait become stable.
+/// of the [`Global`] type when it and the [`AllocRef`] trait become stable.
 ///
 /// # Safety
 ///
 /// See [`GlobalAlloc::realloc`].
 ///
 /// [`Global`]: struct.Global.html
-/// [`Alloc`]: trait.Alloc.html
+/// [`AllocRef`]: trait.AllocRef.html
 /// [`GlobalAlloc::realloc`]: trait.GlobalAlloc.html#method.realloc
 #[stable(feature = "global_alloc", since = "1.28.0")]
 #[inline]
@@ -132,14 +132,14 @@ pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8
 /// if there is one, or the `std` crate’s default.
 ///
 /// This function is expected to be deprecated in favor of the `alloc_zeroed` method
-/// of the [`Global`] type when it and the [`Alloc`] trait become stable.
+/// of the [`Global`] type when it and the [`AllocRef`] trait become stable.
 ///
 /// # Safety
 ///
 /// See [`GlobalAlloc::alloc_zeroed`].
 ///
 /// [`Global`]: struct.Global.html
-/// [`Alloc`]: trait.Alloc.html
+/// [`AllocRef`]: trait.AllocRef.html
 /// [`GlobalAlloc::alloc_zeroed`]: trait.GlobalAlloc.html#method.alloc_zeroed
 ///
 /// # Examples
@@ -163,7 +163,7 @@ pub unsafe fn alloc_zeroed(layout: Layout) -> *mut u8 {
 }
 
 #[unstable(feature = "allocator_api", issue = "32838")]
-unsafe impl Alloc for Global {
+unsafe impl AllocRef for Global {
     #[inline]
     unsafe fn alloc(&mut self, layout: Layout) -> Result<NonNull<u8>, AllocErr> {
         NonNull::new(alloc(layout)).ok_or(AllocErr)
diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index 87a4924f9be..8735c2c8f36 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -145,7 +145,7 @@ use core::ptr::{self, NonNull, Unique};
 use core::slice;
 use core::task::{Context, Poll};
 
-use crate::alloc::{self, Alloc, Global};
+use crate::alloc::{self, AllocRef, Global};
 use crate::raw_vec::RawVec;
 use crate::str::from_boxed_utf8_unchecked;
 use crate::vec::Vec;
diff --git a/src/liballoc/collections/btree/node.rs b/src/liballoc/collections/btree/node.rs
index d9cdebb4f73..c0a96e89366 100644
--- a/src/liballoc/collections/btree/node.rs
+++ b/src/liballoc/collections/btree/node.rs
@@ -36,7 +36,7 @@ use core::mem::{self, MaybeUninit};
 use core::ptr::{self, NonNull, Unique};
 use core::slice;
 
-use crate::alloc::{Alloc, Global, Layout};
+use crate::alloc::{AllocRef, Global, Layout};
 use crate::boxed::Box;
 
 const B: usize = 6;
diff --git a/src/liballoc/raw_vec.rs b/src/liballoc/raw_vec.rs
index 86aed612efe..e1b549bed18 100644
--- a/src/liballoc/raw_vec.rs
+++ b/src/liballoc/raw_vec.rs
@@ -7,7 +7,7 @@ use core::ops::Drop;
 use core::ptr::{self, NonNull, Unique};
 use core::slice;
 
-use crate::alloc::{handle_alloc_error, Alloc, AllocErr, Global, Layout};
+use crate::alloc::{handle_alloc_error, AllocErr, AllocRef, Global, Layout};
 use crate::boxed::Box;
 use crate::collections::TryReserveError::{self, *};
 
@@ -42,13 +42,13 @@ mod tests;
 /// field. This allows zero-sized types to not be special-cased by consumers of
 /// this type.
 #[allow(missing_debug_implementations)]
-pub struct RawVec<T, A: Alloc = Global> {
+pub struct RawVec<T, A: AllocRef = Global> {
     ptr: Unique<T>,
     cap: usize,
     a: A,
 }
 
-impl<T, A: Alloc> RawVec<T, A> {
+impl<T, A: AllocRef> RawVec<T, A> {
     /// Like `new`, but parameterized over the choice of allocator for
     /// the returned `RawVec`.
     pub const fn new_in(a: A) -> Self {
@@ -147,7 +147,7 @@ impl<T> RawVec<T, Global> {
     }
 }
 
-impl<T, A: Alloc> RawVec<T, A> {
+impl<T, A: AllocRef> RawVec<T, A> {
     /// Reconstitutes a `RawVec` from a pointer, capacity, and allocator.
     ///
     /// # Undefined Behavior
@@ -182,7 +182,7 @@ impl<T> RawVec<T, Global> {
     }
 }
 
-impl<T, A: Alloc> RawVec<T, A> {
+impl<T, A: AllocRef> RawVec<T, A> {
     /// Gets a raw pointer to the start of the allocation. Note that this is
     /// `Unique::empty()` if `capacity == 0` or `T` is zero-sized. In the former case, you must
     /// be careful.
@@ -622,7 +622,7 @@ enum ReserveStrategy {
 
 use ReserveStrategy::*;
 
-impl<T, A: Alloc> RawVec<T, A> {
+impl<T, A: AllocRef> RawVec<T, A> {
     fn reserve_internal(
         &mut self,
         used_capacity: usize,
@@ -700,7 +700,7 @@ impl<T> RawVec<T, Global> {
     }
 }
 
-impl<T, A: Alloc> RawVec<T, A> {
+impl<T, A: AllocRef> RawVec<T, A> {
     /// Frees the memory owned by the `RawVec` *without* trying to drop its contents.
     pub unsafe fn dealloc_buffer(&mut self) {
         let elem_size = mem::size_of::<T>();
@@ -712,7 +712,7 @@ impl<T, A: Alloc> RawVec<T, A> {
     }
 }
 
-unsafe impl<#[may_dangle] T, A: Alloc> Drop for RawVec<T, A> {
+unsafe impl<#[may_dangle] T, A: AllocRef> Drop for RawVec<T, A> {
     /// Frees the memory owned by the `RawVec` *without* trying to drop its contents.
     fn drop(&mut self) {
         unsafe {
diff --git a/src/liballoc/raw_vec/tests.rs b/src/liballoc/raw_vec/tests.rs
index b214cef3011..63087501f0e 100644
--- a/src/liballoc/raw_vec/tests.rs
+++ b/src/liballoc/raw_vec/tests.rs
@@ -19,7 +19,7 @@ fn allocator_param() {
     struct BoundedAlloc {
         fuel: usize,
     }
-    unsafe impl Alloc for BoundedAlloc {
+    unsafe impl AllocRef for BoundedAlloc {
         unsafe fn alloc(&mut self, layout: Layout) -> Result<NonNull<u8>, AllocErr> {
             let size = layout.size();
             if size > self.fuel {
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index b176e0f6e2a..9dc5447397f 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -252,7 +252,7 @@ use core::ptr::{self, NonNull};
 use core::slice::{self, from_raw_parts_mut};
 use core::usize;
 
-use crate::alloc::{box_free, handle_alloc_error, Alloc, Global, Layout};
+use crate::alloc::{box_free, handle_alloc_error, AllocRef, Global, Layout};
 use crate::string::String;
 use crate::vec::Vec;
 
diff --git a/src/liballoc/sync.rs b/src/liballoc/sync.rs
index 4aa0190b149..fd285242d5b 100644
--- a/src/liballoc/sync.rs
+++ b/src/liballoc/sync.rs
@@ -25,7 +25,7 @@ use core::sync::atomic;
 use core::sync::atomic::Ordering::{Acquire, Relaxed, Release, SeqCst};
 use core::{isize, usize};
 
-use crate::alloc::{box_free, handle_alloc_error, Alloc, Global, Layout};
+use crate::alloc::{box_free, handle_alloc_error, AllocRef, Global, Layout};
 use crate::boxed::Box;
 use crate::rc::is_dangling;
 use crate::string::String;
diff --git a/src/liballoc/tests/heap.rs b/src/liballoc/tests/heap.rs
index 43cd7187823..7fcfcf9b294 100644
--- a/src/liballoc/tests/heap.rs
+++ b/src/liballoc/tests/heap.rs
@@ -1,4 +1,4 @@
-use std::alloc::{Alloc, Global, Layout, System};
+use std::alloc::{AllocRef, Global, Layout, System};
 
 /// Issue #45955 and #62251.
 #[test]
@@ -11,7 +11,7 @@ fn std_heap_overaligned_request() {
     check_overalign_requests(Global)
 }
 
-fn check_overalign_requests<T: Alloc>(mut allocator: T) {
+fn check_overalign_requests<T: AllocRef>(mut allocator: T) {
     for &align in &[4, 8, 16, 32] {
         // less than and bigger than `MIN_ALIGN`
         for &size in &[align / 2, align - 1] {
diff --git a/src/libcore/alloc.rs b/src/libcore/alloc.rs
index 09f743fb81e..1b7dfafbd70 100644
--- a/src/libcore/alloc.rs
+++ b/src/libcore/alloc.rs
@@ -31,7 +31,7 @@ const fn size_align<T>() -> (usize, usize) {
 ///
 /// (Note however that layouts are *not* required to have positive
 /// size, even though many allocators require that all memory
-/// requests have positive size. A caller to the `Alloc::alloc`
+/// requests have positive size. A caller to the `AllocRef::alloc`
 /// method must either ensure that conditions like this are met, or
 /// use specific allocators with looser requirements.)
 #[stable(feature = "alloc_layout", since = "1.28.0")]
@@ -364,8 +364,8 @@ impl fmt::Display for AllocErr {
 /// [`shrink_in_place`] were unable to reuse the given memory block for
 /// a requested layout.
 ///
-/// [`grow_in_place`]: ./trait.Alloc.html#method.grow_in_place
-/// [`shrink_in_place`]: ./trait.Alloc.html#method.shrink_in_place
+/// [`grow_in_place`]: ./trait.AllocRef.html#method.grow_in_place
+/// [`shrink_in_place`]: ./trait.AllocRef.html#method.shrink_in_place
 #[unstable(feature = "allocator_api", issue = "32838")]
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct CannotReallocInPlace;
@@ -580,9 +580,14 @@ pub unsafe trait GlobalAlloc {
     }
 }
 
-/// An implementation of `Alloc` can allocate, reallocate, and
+/// An implementation of `AllocRef` can allocate, reallocate, and
 /// deallocate arbitrary blocks of data described via `Layout`.
 ///
+/// `AllocRef` is designed to be implemented on ZSTs, references, or
+/// smart pointers because having an allocator like `MyAlloc([u8; N])`
+/// cannot be moved, without updating the pointers to the allocated
+/// memory.
+///
 /// Some of the methods require that a memory block be *currently
 /// allocated* via an allocator. This means that:
 ///
@@ -598,7 +603,7 @@ pub unsafe trait GlobalAlloc {
 ///   passed to a reallocation method (see above) that returns `Ok`.
 ///
 /// A note regarding zero-sized types and zero-sized layouts: many
-/// methods in the `Alloc` trait state that allocation requests
+/// methods in the `AllocRef` trait state that allocation requests
 /// must be non-zero size, or else undefined behavior can result.
 ///
 /// * However, some higher-level allocation methods (`alloc_one`,
@@ -606,7 +611,7 @@ pub unsafe trait GlobalAlloc {
 ///   optionally support them: it is left up to the implementor
 ///   whether to return `Err`, or to return `Ok` with some pointer.
 ///
-/// * If an `Alloc` implementation chooses to return `Ok` in this
+/// * If an `AllocRef` implementation chooses to return `Ok` in this
 ///   case (i.e., the pointer denotes a zero-sized inaccessible block)
 ///   then that returned pointer must be considered "currently
 ///   allocated". On such an allocator, *all* methods that take
@@ -646,13 +651,16 @@ pub unsafe trait GlobalAlloc {
 ///
 /// # Safety
 ///
-/// The `Alloc` trait is an `unsafe` trait for a number of reasons, and
+/// The `AllocRef` trait is an `unsafe` trait for a number of reasons, and
 /// implementors must ensure that they adhere to these contracts:
 ///
 /// * Pointers returned from allocation functions must point to valid memory and
-///   retain their validity until at least the instance of `Alloc` is dropped
+///   retain their validity until at least one instance of `AllocRef` is dropped
 ///   itself.
 ///
+/// * Cloning or moving the allocator must not invalidate pointers returned
+///   from this allocator. Cloning must return a reference to the same allocator.
+///
 /// * `Layout` queries and calculations in general must be correct. Callers of
 ///   this trait are allowed to rely on the contracts defined on each method,
 ///   and implementors must ensure such contracts remain true.
@@ -660,7 +668,7 @@ pub unsafe trait GlobalAlloc {
 /// Note that this list may get tweaked over time as clarifications are made in
 /// the future.
 #[unstable(feature = "allocator_api", issue = "32838")]
-pub unsafe trait Alloc {
+pub unsafe trait AllocRef {
     // (Note: some existing allocators have unspecified but well-defined
     // behavior in response to a zero size allocation request ;
     // e.g., in C, `malloc` of 0 will either return a null pointer or a
@@ -1042,7 +1050,7 @@ pub unsafe trait Alloc {
     /// must be considered "currently allocated" and must be
     /// acceptable input to methods such as `realloc` or `dealloc`,
     /// *even if* `T` is a zero-sized type. In other words, if your
-    /// `Alloc` implementation overrides this method in a manner
+    /// `AllocRef` implementation overrides this method in a manner
     /// that can return a zero-sized `ptr`, then all reallocation and
     /// deallocation methods need to be similarly overridden to accept
     /// such values as input.
@@ -1106,7 +1114,7 @@ pub unsafe trait Alloc {
     /// must be considered "currently allocated" and must be
     /// acceptable input to methods such as `realloc` or `dealloc`,
     /// *even if* `T` is a zero-sized type. In other words, if your
-    /// `Alloc` implementation overrides this method in a manner
+    /// `AllocRef` implementation overrides this method in a manner
     /// that can return a zero-sized `ptr`, then all reallocation and
     /// deallocation methods need to be similarly overridden to accept
     /// such values as input.
@@ -1219,3 +1227,10 @@ pub unsafe trait Alloc {
         }
     }
 }
+
+// In order to rename `Alloc` to `AllocRef`, some submoduleshas to be updated as well. The CI fails
+// if either of the submodules fails to compile. The submodules have their own CI depending on a
+// specific Rust version, which don't have `AllocRef` yet. This alias is used to make the submodules
+// compile and pass the CI.
+#[unstable(feature = "allocator_api", issue = "32838")]
+pub use self::AllocRef as Alloc;
diff --git a/src/libstd/alloc.rs b/src/libstd/alloc.rs
index 7fd55af1694..8965c6860c4 100644
--- a/src/libstd/alloc.rs
+++ b/src/libstd/alloc.rs
@@ -133,9 +133,9 @@ pub use alloc_crate::alloc::*;
 #[derive(Debug, Default, Copy, Clone)]
 pub struct System;
 
-// The Alloc impl just forwards to the GlobalAlloc impl, which is in `std::sys::*::alloc`.
+// The AllocRef impl just forwards to the GlobalAlloc impl, which is in `std::sys::*::alloc`.
 #[unstable(feature = "allocator_api", issue = "32838")]
-unsafe impl Alloc for System {
+unsafe impl AllocRef for System {
     #[inline]
     unsafe fn alloc(&mut self, layout: Layout) -> Result<NonNull<u8>, AllocErr> {
         NonNull::new(GlobalAlloc::alloc(self, layout)).ok_or(AllocErr)
diff --git a/src/test/ui/allocator-alloc-one.rs b/src/test/ui/allocator-alloc-one.rs
index 312d5f13b1a..b821a2c5939 100644
--- a/src/test/ui/allocator-alloc-one.rs
+++ b/src/test/ui/allocator-alloc-one.rs
@@ -4,7 +4,7 @@
 
 #![feature(allocator_api, nonnull)]
 
-use std::alloc::{Alloc, Global, Layout, handle_alloc_error};
+use std::alloc::{AllocRef, Global, Layout, handle_alloc_error};
 
 fn main() {
     unsafe {
diff --git a/src/test/ui/allocator/custom.rs b/src/test/ui/allocator/custom.rs
index 71f72ae46c2..0b1f6d5a96e 100644
--- a/src/test/ui/allocator/custom.rs
+++ b/src/test/ui/allocator/custom.rs
@@ -7,7 +7,7 @@
 
 extern crate helper;
 
-use std::alloc::{self, Global, Alloc, System, Layout};
+use std::alloc::{self, Global, AllocRef, System, Layout};
 use std::sync::atomic::{AtomicUsize, Ordering};
 
 static HITS: AtomicUsize = AtomicUsize::new(0);
diff --git a/src/test/ui/allocator/xcrate-use.rs b/src/test/ui/allocator/xcrate-use.rs
index 039c70e77be..37b28c195df 100644
--- a/src/test/ui/allocator/xcrate-use.rs
+++ b/src/test/ui/allocator/xcrate-use.rs
@@ -9,7 +9,7 @@
 extern crate custom;
 extern crate helper;
 
-use std::alloc::{Global, Alloc, System, Layout};
+use std::alloc::{Global, AllocRef, System, Layout};
 use std::sync::atomic::{Ordering, AtomicUsize};
 
 #[global_allocator]
diff --git a/src/test/ui/realloc-16687.rs b/src/test/ui/realloc-16687.rs
index 69292d241c3..425aa83e70a 100644
--- a/src/test/ui/realloc-16687.rs
+++ b/src/test/ui/realloc-16687.rs
@@ -6,7 +6,7 @@
 
 #![feature(allocator_api)]
 
-use std::alloc::{Global, Alloc, Layout, handle_alloc_error};
+use std::alloc::{Global, AllocRef, Layout, handle_alloc_error};
 use std::ptr::{self, NonNull};
 
 fn main() {
diff --git a/src/test/ui/regions/regions-mock-codegen.rs b/src/test/ui/regions/regions-mock-codegen.rs
index 521ef3f6a4b..f50b1c8b17f 100644
--- a/src/test/ui/regions/regions-mock-codegen.rs
+++ b/src/test/ui/regions/regions-mock-codegen.rs
@@ -6,7 +6,7 @@
 
 #![feature(allocator_api)]
 
-use std::alloc::{Alloc, Global, Layout, handle_alloc_error};
+use std::alloc::{AllocRef, Global, Layout, handle_alloc_error};
 use std::ptr::NonNull;
 
 struct arena(());