error: Undefined Behavior: constructing invalid value: encountered invalid reference metadata: slice is bigger than largest supported object
  --> $DIR/too-big-slice.rs:LL:CC
   |
LL |         let _x: &[u8] = mem::transmute((ptr, usize::MAX));
   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered invalid reference metadata: slice is bigger than largest supported object
   |
   = 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 `main` at $DIR/too-big-slice.rs:LL:CC

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

error: aborting due to previous error