syntax_data: {"ast_node_type":"variable","tokens":[{"end":64,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                             let sm = self.tcx.sess.source_map();
context_before:                         scrut.span.find_ancestor_in_same_ctxt(expr_span).and_then(|scrut_span| {
context_after:                             let brace_span = sm.span_extend_to_next_char(scrut_span, '{', true);