syntax_data: {"ast_node_type":"variable","tokens":[{"end":74,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let Some(rhs) = self.register_place(*rhs) else { return };
context_before:                 let Some(lhs) = self.register_place(*lhs) else { return };
context_after:                 self.assignments.insert((lhs, rhs));