syntax_data: {"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// T` is covariant with respect to `T`, so the variance within
context_before:     /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
context_after:     /// which the first `Vec<i32>` appears is