syntax_data: {"ast_node_type":"other","tokens":[{"end":80,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // Could partial array tracking work off something else instead?
context_before:                 // though. FIXME: Do we really *need* to count this as a use?
context_after:                 self.cfg.push_fake_read(block, source_info, FakeReadCause::ForIndex, place);