pub(crate) fn zst(layout: TyAndLayout<'tcx>) -> CValue<'tcx> {
        assert!(layout.is_zst());
        CValue::by_ref(crate::Pointer::dangling(layout.align.abi), layout)
    }
Create an instance of a ZST

The is represented by a dangling pointer of suitable alignment.
src/value_and_place.rs