1 error: Undefined Behavior: overflow computing total size of `copy`
2 --> $DIR/copy_overflow.rs:LL:CC
4 LL | (&mut y as *mut i32).copy_from(&x, 1usize << (mem::size_of::<usize>() * 8 - 1));
5 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow computing total size of `copy`
7 = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
8 = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
10 = note: inside `main` at $DIR/copy_overflow.rs:LL:CC
12 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
14 error: aborting due to previous error