syntax_data: {"ast_node_type":"variable","tokens":[{"end":73,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let lhs = unpack!(block = this.as_place(block, lhs));
context_before:                     let rhs = unpack!(block = this.as_local_rvalue(block, rhs));
context_after:                     this.cfg.push_assign(block, source_info, lhs, rhs);