error: Undefined Behavior: out-of-bounds pointer use: 0x4[noalloc] is a dangling pointer (it has no provenance) --> RUSTLIB/alloc/src/boxed.rs:LL:CC | LL | Box(unsafe { Unique::new_unchecked(raw) }, alloc) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: 0x4[noalloc] is a dangling pointer (it has no provenance) | = 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 `std::boxed::Box::::from_raw_in` at RUSTLIB/alloc/src/boxed.rs:LL:CC = note: inside `std::boxed::Box::::from_raw` at RUSTLIB/alloc/src/boxed.rs:LL:CC note: inside `main` at $DIR/issue-miri-1050-2.rs:LL:CC --> $DIR/issue-miri-1050-2.rs:LL:CC | LL | drop(Box::from_raw(ptr.as_ptr())); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace error: aborting due to previous error