syntax_data: {"ast_node_type":"other","tokens":[{"end":92,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                     // a scrutinee place. `scrutinee_place_builder` will fail to be resolved
context_before:                     // `PlaceBuilder` inside a closure. In this case, we don't want to include
context_after:                     // if the only match arm is a wildcard (`_`).