{"ast_node_type":"other","tokens":[{"end":40,"kind":"keyword","start":0,"text":"///"}]}
    /// such a constraint, if it exists.
    /// for the program to type-check). `only_has_type` will return
    pub(super) fn only_has_type(self, fcx: &FnCtxt<'a, 'tcx>) -> Option<Ty<'tcx>> {