#![feature(allocator_api)]

use std::{
    alloc::{Allocator, Global, System},
    sync::Arc,
};

pub trait NewTrait: Allocator {}
impl<A: Allocator> NewTrait for A {}

impl Clone for Box<dyn NewTrait> { // valid because Box is special and NewTrait is a local type
    fn clone(&self) -> Self {
        // safe clone impl that violates the safety
        // requirements of Allocator because now,
        // Self: Allocator + Clone but the clone is different
        Box::new(System)
    }
}

use jemallocator::Jemalloc;

#[global_allocator]
static GLOBAL: Jemalloc = Jemalloc;

fn main() {
    let evil_arc = Arc::new_in(69420, Box::new(Global) as Box<dyn NewTrait>);
    let wat = evil_arc.clone(); // clone() returns the wrong allocator
    drop(evil_arc);
    drop(wat); // free(): invalid pointer
}