{"ast_node_type":"function","tokens":[{"end":40,"kind":"keyword","start":0,"text":"pub"}]}
    pub fn expect_ty(self) -> Ty<'tcx> {
    /// to be limited (e.g. in tuples, where the only parameters are type parameters).
        self.as_type().unwrap_or_else(|| bug!("expected a type, but found another kind"))