{"ast_node_type":"variable","tokens":[{"end":65,"kind":"keyword","start":0,"text":"let"}]}
        let assoc_item = ast::AssocItem::TypeAlias(source.value);
    if let Some(source) = ctx.sema.source(type_alias) {
        if let Some(transformed_item) = get_transformed_assoc_item(ctx, assoc_item, impl_def) {