syntax_data: {"ast_node_type":"enum","tokens":[{"end":19,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet: pub enum Variance {
context_before: #[cfg_attr(feature = "nightly", rustc_pass_by_value)]
context_after:     Covariant,     // T<A> <: T<B> iff A <: B -- e.g., function return type