syntax_data: {"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let dcx = DiagCtxt::new(Box::new(FatalOnlyEmitter {
context_before:             Box::new(HumanEmitter::new(stderr_destination(ColorConfig::Auto), translator));
context_after:             fatal_emitter,