Use allocator-api through allocator-api2 crate

Cargo.toml

@@ -30,6 +30,9 @@ name = "try_alloc"
 path = "tests/try_alloc.rs"
 harness = false
 
+[dependencies]
+allocator-api2 = { version = "0.2.6" }
+
 [dev-dependencies]
 quickcheck = "1.0.3"
 criterion = "0.3.6"
@@ -39,7 +42,7 @@ rand = "0.8.5"
 default = []
 collections = []
 boxed = []
-allocator_api = []
+allocator_api = ["allocator-api2/nightly"]
 
 # [profile.bench]
 # debug = true

src/lib.rs

@@ -2,10 +2,7 @@
 #![deny(missing_debug_implementations)]
 #![deny(missing_docs)]
 #![no_std]
-#![cfg_attr(
-    feature = "allocator_api",
-    feature(allocator_api, nonnull_slice_from_raw_parts)
-)]
+#![cfg_attr(feature = "allocator_api", feature(allocator_api))]
 
 #[doc(hidden)]
 pub extern crate alloc as core_alloc;
@@ -25,9 +22,8 @@ use core::mem;
 use core::ptr::{self, NonNull};
 use core::slice;
 use core::str;
-use core_alloc::alloc::{alloc, dealloc, Layout};
-#[cfg(feature = "allocator_api")]
-use core_alloc::alloc::{AllocError, Allocator};
+
+use allocator_api2::alloc::{alloc, dealloc, AllocError, Allocator, Layout};
 
 pub use alloc::AllocErr;
 
@@ -1886,11 +1882,12 @@ unsafe impl<'a> alloc::Alloc for &'a Bump {
     }
 }
 
-#[cfg(feature = "allocator_api")]
 unsafe impl<'a> Allocator for &'a Bump {
     fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
         self.try_alloc_layout(layout)
-            .map(|p| NonNull::slice_from_raw_parts(p, layout.size()))
+            .map(|p| unsafe {
+                NonNull::new_unchecked(ptr::slice_from_raw_parts_mut(p.as_ptr(), layout.size()))
+            })
             .map_err(|_| AllocError)
     }
 
@@ -1905,7 +1902,9 @@ unsafe impl<'a> Allocator for &'a Bump {
         new_layout: Layout,
     ) -> Result<NonNull<[u8]>, AllocError> {
         Bump::shrink(self, ptr, old_layout, new_layout)
-            .map(|p| NonNull::slice_from_raw_parts(p, new_layout.size()))
+            .map(|p| unsafe {
+                NonNull::new_unchecked(ptr::slice_from_raw_parts_mut(p.as_ptr(), new_layout.size()))
+            })
             .map_err(|_| AllocError)
     }
 
@@ -1916,7 +1915,9 @@ unsafe impl<'a> Allocator for &'a Bump {
         new_layout: Layout,
     ) -> Result<NonNull<[u8]>, AllocError> {
         Bump::grow(self, ptr, old_layout, new_layout)
-            .map(|p| NonNull::slice_from_raw_parts(p, new_layout.size()))
+            .map(|p| unsafe {
+                NonNull::new_unchecked(ptr::slice_from_raw_parts_mut(p.as_ptr(), new_layout.size()))
+            })
             .map_err(|_| AllocError)
     }