syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     ///    ([util::collect_fake_borrows]).
context_before:     ///    matched against and create the required temporaries for them
context_after:     /// 4. Create everything else: the guards and the arms ([Builder::lower_match_arms]).