syntax_data: {"ast_node_type":"other","tokens":[{"end":68,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: /// This is only used to add more information to error messages, and
context_before: /// Extra information about why we ended up with a particular variance.
context_after: /// has no effect on soundness. While choosing the 'wrong' `VarianceDiagInfo`