{"ast_node_type":"other","tokens":[{"end":73,"kind":"keyword","start":0,"text":"//"}]}
    // example, instead of `MyType<'a, T>`, it will be `MyType<'a, __S>`.
    // Create unsized `self`, that is, one where the `#[pointee]` type arg is replaced with `__S`. For
    let s_ty = cx.ty_ident(span, Ident::new(sym::__S, span));