#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(align_to_uninit_mut)]
use std::mem::MaybeUninit;
pub struct BumpAllocator<'scope> {
    memory: &'scope mut [MaybeUninit<u8>],
}
impl<'scope> BumpAllocator<'scope> {
    pub fn new(memory: &'scope mut [MaybeUninit<u8>]) -> Self {
        Self { memory }
    }
    pub fn try_alloc_uninit<T>(&mut self) -> Option<&'scope mut MaybeUninit<T>> {
        let first_end = self.memory.as_ptr().align_offset(align_of::<T>())
            + size_of::<T>();
        let prefix = self.memory.split_off_mut(..first_end)?;
        Some(&mut prefix.align_to_uninit_mut::<T>().1[0])
    }
    pub fn try_alloc_u32(&mut self, value: u32) -> Option<&'scope mut u32> {
        let uninit = self.try_alloc_uninit()?;
        Some(uninit.write(value))
    }
}
fn main() {
    let mut memory = [MaybeUninit::<u8>::uninit(); 10];
    let mut allocator = BumpAllocator::new(&mut memory);
    let v = allocator.try_alloc_u32(42);
    assert_eq!(v, Some(& mut 42));
}