{"ast_node_type":"function","tokens":[{"end":49,"kind":"keyword","start":0,"text":"fn"}]}
    fn isnt_macro_invocation(&mut self) -> bool {
    /// Are we sure this could not possibly be a macro invocation?
        self.check_ident() && self.look_ahead(1, |t| *t != token::Bang && *t != token::PathSep)