{"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"///"}]}
///     - similarly, `FundamentalPair<LocalType<T>, T>` is bad, because
///     `LocalType<T>`, and `Vec<->` is between it and the type parameter.
///     the second occurrence of `T` is not a subtree of *any* local type.