syntax_data: {"ast_node_type":"variable","tokens":[{"end":61,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let success = this.cfg.start_new_block();
context_before:                     // Convert `expr.use` to a call like `Clone::clone(&expr)`
context_after:                     let clone_trait = this.tcx.require_lang_item(LangItem::Clone, span);