syntax_data: {"ast_node_type":"other","tokens":[{"end":18,"kind":"keyword","start":0,"text":"Object(usize),"}]}
source_snippet:     Object(usize),
context_before:     /// A built-in impl for trait objects. The index is only used in winnowing.
context_after:     /// A built-in implementation of `Upcast` for trait objects to other trait objects.