{"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"///"}]}
    /// for types other than `ty::Infer(_)` (or `InferTy::Fresh*`).
    /// Tries to extract an inference variable from a type, returns `None`
    fn maybe_from_ty(ty: Ty<'tcx>) -> Option<Self> {