syntax_data: {"ast_node_type":"other","tokens":[{"end":68,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
context_before:     /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
context_after:     /// respect to its type argument `T`, and hence the variance of