syntax_data: {"ast_node_type":"variable","tokens":[{"end":54,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:     if let Err(e) = tcx.ensure_ok().check_match(def) {
context_before:     tcx.ensure_done().thir_abstract_const(def);
context_after:         return construct_error(tcx, def, e);