syntax_data: {"ast_node_type":"function","tokens":[{"end":52,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// fetching the `typeck` the enclosing fn item.
context_before:     /// `typeck` the closure, for example, we really wind up
context_after:     pub fn typeck_root_def_id(self, def_id: DefId) -> DefId {