syntax_data: {"ast_node_type":"variable","tokens":[{"end":46,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let (thir, expr) = tcx.thir_body(def_id)?;
context_before:     let typeck_results = tcx.typeck(def_id);
context_after:     let thir = thir.borrow();