#![feature(allocator_api)]

use std::alloc::{Allocator, AllocError, Layout, Global};
use std::ptr::NonNull;

struct LoudDropAllocator;

unsafe impl Allocator for LoudDropAllocator {
    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
        Global.allocate(layout)
    }
    unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
        Global.deallocate(ptr, layout);
    }
}
impl Drop for LoudDropAllocator {
    fn drop(&mut self) {
        println!("dropping allocator...");
    }
}

struct HasDrop;
impl Drop for HasDrop {
    fn drop(&mut self) {}
}

fn foo() {
    println!("foo()");
    let b = Box::new_in(HasDrop, LoudDropAllocator);
    if true {
        drop(*b);
    } else {
        drop(b);
    }
}

fn bar() {
    println!("bar()");
    let b = Box::new_in(HasDrop, LoudDropAllocator);
    if true {
        drop(*b);
    } else {
        // drop(b);
    }
}

fn main() {
    foo();
    bar();
}