error: Undefined Behavior: overflow computing total size of `write_bytes`
  --> RUSTLIB/core/src/intrinsics.rs:LL:CC
   |
LL |         write_bytes(dst, val, count)
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow computing total size of `write_bytes`
   |
   = 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 `std::intrinsics::write_bytes::<i32>` at RUSTLIB/core/src/intrinsics.rs:LL:CC
   = note: inside `std::ptr::mut_ptr::<impl *mut i32>::write_bytes` at RUSTLIB/core/src/ptr/mut_ptr.rs:LL:CC
note: inside `main` at $DIR/write_bytes_overflow.rs:LL:CC
  --> $DIR/write_bytes_overflow.rs:LL:CC
   |
LL |         (&mut y as *mut i32).write_bytes(0u8, 1usize << (mem::size_of::<usize>() * 8 - 1));
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

error: aborting due to previous error