LinkedList::remove forgets the allocator

[xTachyon]

I tried this code:

#![feature(allocator_api)]
#![feature(linked_list_remove)]

use std::{
    alloc::{AllocError, Allocator, Layout},
    collections::LinkedList,
    process::abort,
    ptr::NonNull,
};

struct M;

unsafe impl Allocator for M {
    fn allocate(&self, layout: std::alloc::Layout) -> Result<NonNull<[u8]>, AllocError> {
        unsafe {
            if layout.align() > std::mem::align_of::<usize>() {
                abort();
            }
            let ptr = libc::malloc(layout.size()) as *mut u8;
            if ptr.is_null() {
                abort();
            }
            println!("alloc: {:?}", ptr);
            let nonnull = NonNull::new_unchecked(ptr);
            Ok(NonNull::slice_from_raw_parts(nonnull, layout.size()))
        }
    }

    unsafe fn deallocate(&self, ptr: NonNull<u8>, _layout: Layout) {
        unsafe {
            println!("dealloc: {:?}", ptr);
            libc::free(ptr.as_ptr() as _);
        }
    }
}

fn main() {
    let alloc = &M;
    let mut list = LinkedList::new_in(alloc);
    list.push_back(5);
    list.remove(0);
}

I expected to see this happen: alloc and dealloc is printed

Instead, this happened: only alloc is printed

Meta

rustc --version --verbose:

rustc 1.80.0-nightly (f67a1acc0 2024-06-01)
binary: rustc
commit-hash: f67a1acc04c7ecbf05751b17592dd8d245b75256
commit-date: 2024-06-01
host: x86_64-unknown-linux-gnu
release: 1.80.0-nightly
LLVM version: 18.1.6

LinkedList::remove forgets that it's been initialized with an allocator, and always deletes the node with the global allocator.

rust/library/alloc/src/collections/linked_list.rs

Line 1708 in 1689a5a

let unlinked_node = Box::from_raw(unlinked_node.as_ptr());

There seems to be one more place where this happens in the same file.

[xTachyon]

@rustbot claim