{"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"//"}]}
                        // but actually supporting that would "expand" to an infinitely-long type
                        // Here, the user could theoretically write `dyn MyTrait<MyOutput = X>`,
                        // `fix $ τ → dyn MyTrait<MyOutput = X, Output = <τ as MyTrait>::MyOutput`.