{"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"//"}]}
        // layout is the same across different ZST type arguments.
        // SAFETY: `ConstArg` is `repr(C)` and `ConstArgKind` is marked `repr(u8)` so that the
        let ptr = self as *const ConstArg<'hir, AmbigArg> as *const ConstArg<'hir, ()>;