syntax_data: {"ast_node_type":"variable","tokens":[{"end":70,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let build_mir = |thir: &Thir<'tcx>| match thir.body_type {
context_before:         Ok((thir, expr)) => {
context_after:                 thir::BodyTy::Fn(fn_sig) => construct_fn(tcx, def, thir, expr, fn_sig),