syntax_data: {"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
context_before:     /// within which both pointer types appear is
context_after:     /// T` is covariant with respect to `T`, so the variance within