{"ast_node_type":"function","tokens":[{"end":84,"kind":"keyword","start":0,"text":"pub(crate)"}]}
    pub(crate) fn parse_pin_and_mut(&mut self) -> Option<(Pinnedness, Mutability)> {
    /// It must be either `pin const` or `pin mut`.
        if self.token.is_ident_named(sym::pin) {