error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
  --> $DIR/dealloc_read_race1.rs:LL:CC
   |
LL | /             __rust_dealloc(
LL | |
LL | |                 ptr.0 as *mut _,
LL | |                 std::mem::size_of::<usize>(),
LL | |                 std::mem::align_of::<usize>(),
LL | |             );
   | |_____________^ Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
   = note: BACKTRACE:
   = note: inside closure at $DIR/dealloc_read_race1.rs:LL:CC

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

error: aborting due to previous error