syntax_data: {"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// might invoke `shift_out_to_binder(D3)`. This would adjust the
context_before:     /// those two binders would not be in scope. In that case, we
context_after:     /// De Bruijn index of `'a` to D1 (the innermost binder).