error[E0080]: memory access failed: attempting to access 1 byte, but got ALLOC0+0x4 which is at or beyond the end of the allocation of size 4 bytes
  --> $DIR/missing_span_in_backtrace.rs:16:9
   |
16 | /         ptr::swap_nonoverlapping(
17 | |             &mut x1 as *mut _ as *mut MaybeUninit<u8>,
18 | |             &mut x2 as *mut _ as *mut MaybeUninit<u8>,
19 | |             10,
20 | |         );
   | |_________^ evaluation of `X` failed inside this call
   |
note: inside `swap_nonoverlapping::compiletime::<MaybeUninit<u8>>`
  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
note: inside `std::ptr::swap_nonoverlapping_const::<MaybeUninit<u8>>`
  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
note: inside `std::ptr::copy_nonoverlapping::<MaybeUninit<u8>>`
  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0080`.