syntax_data: {"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"(Variance::Covariant,"}]}
source_snippet:             (Variance::Covariant, Variance::Contravariant) => Variance::Contravariant,
context_before:             (Variance::Covariant, Variance::Covariant) => Variance::Covariant,
context_after:             (Variance::Covariant, Variance::Invariant) => Variance::Invariant,