syntax_data: {"ast_node_type":"variable","tokens":[{"end":32,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let mut result = Ok(());
context_before:     fn parse(tcx: TyCtxt<'_>, def_id: DefId) -> Result<Self, ()> {
context_after:         let mut ret = RustcMirAttrs::default();