error: memory leaked: ALLOC (Rust heap, size: 4, align: 4), allocated here:
  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
   |
LL |         __rust_alloc(layout.size(), layout.align())
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: inside `std::alloc::alloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
   = note: inside `std::alloc::Global::alloc_impl` at RUSTLIB/alloc/src/alloc.rs:LL:CC
   = note: inside `<std::alloc::Global as std::alloc::Allocator>::allocate` at RUSTLIB/alloc/src/alloc.rs:LL:CC
   = note: inside `alloc::alloc::exchange_malloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
   = note: inside `std::boxed::Box::<i32>::new` at RUSTLIB/alloc/src/boxed.rs:LL:CC
note: inside `main`
  --> $DIR/memleak.rs:LL:CC
   |
LL |     std::mem::forget(Box::new(42));
   |                      ^^^^^^^^^^^^

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

note: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check

error: aborting due to 1 previous error