{"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"PrimTy::Float(FloatTy::F128)"}]}
                    PrimTy::Float(FloatTy::F128) if !tcx.features().f128() => {
                    }
                        Some((sym::f128, "the type `f128` is unstable"))