error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
  --> $DIR/rc_as_ptr.rs:LL:CC
   |
LL |     assert_eq!(42, **unsafe { &*Weak::as_ptr(&weak) });
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
   |
   = 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 RUSTLIB/core/src/macros/mod.rs:LL:CC
   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)

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

error: aborting due to previous error