syntax_data: {"ast_node_type":"other","tokens":[{"end":73,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// argument to the inner function. This region `'b` is assigned a De
context_before:     /// Let's start with the reference type `&'b isize` that is the first
context_after:     /// Bruijn index of 0, meaning "the innermost binder" (in this case, a