error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 4, so pointer to 4 bytes starting at offset -XX is out-of-bounds
  --> $DIR/ptr_legacy_provenance.rs:LL:CC
   |
LL |     assert_eq!(unsafe { *ptr }, 0);
   |                         ^^^^ dereferencing pointer failed: ALLOC has size 4, so pointer to 4 bytes starting at offset -XX is out-of-bounds
   |
   = 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: inside `main` at $DIR/ptr_legacy_provenance.rs:LL:CC

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

error: aborting due to previous error