syntax_data: {"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"Dynamic(I::BoundExistentialPredicates,"}]}
source_snippet:     Dynamic(I::BoundExistentialPredicates, I::Region, DynKind),
context_before:     /// A trait object. Written as `dyn for<'b> Trait<'b, Assoc = u32> + Send + 'a`.