syntax_data: {"ast_node_type":"other","tokens":[{"end":30,"kind":"keyword","start":0,"text":"ty::Covariant"}]}
source_snippet:             ty::Covariant => {
context_before:             // [rd]: https://rustc-dev-guide.rust-lang.org/borrow_check/region_inference/placeholders_and_universes.html
context_after:                 self.infcx.enter_forall(b, |b| {