Swap to rustc feature allocator_ext instead of allocator_api

examples/allocator_api.rs

@@ -1,5 +1,4 @@
 //! This examples requires nightly for the allocator API.
-#![feature(allocator_api)]
 #![no_std]
 #![no_main]
 
@@ -11,7 +10,7 @@ use cortex_m_rt::entry;
 use defmt_semihosting as _;
 use embedded_alloc::LlffHeap as Heap;
 
-// This is not used, but as of 2023-10-29 allocator_api cannot be used without
+// This is not used, but as of 2026-09-27 `alloc` collections cannot be used without it, even when using only a local allocator.
 // a global heap
 #[global_allocator]
 static HEAP: Heap = Heap::empty();

examples/llff_integration_test.rs

@@ -12,7 +12,6 @@
 //!
 //! [Embedded Rust Book]: https://docs.rust-embedded.org/book/intro/index.html
 
-#![feature(allocator_api)]
 #![no_main]
 #![no_std]
 

examples/tlsf_integration_test.rs

@@ -12,7 +12,7 @@
 //!
 //! [Embedded Rust Book]: https://docs.rust-embedded.org/book/intro/index.html
 
-#![feature(allocator_api)]
+#![feature(allocator_ext)]
 #![no_main]
 #![no_std]
 

src/lib.rs

@@ -1,6 +1,5 @@
 #![doc = include_str!("../README.md")]
 #![no_std]
-#![cfg_attr(feature = "allocator_api", feature(allocator_api))]
 #![warn(missing_docs)]
 
 #[cfg(feature = "llff")]