error[E0793]: reference to packed field is unaligned --> $DIR/repr_packed.rs:21:24 | LL | println!("{}", foo.x); | ^^^^^ | = note: packed structs are only aligned by one byte, and many modern architectures penalize unaligned field accesses = note: creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0793`.