syntax_data: {"ast_node_type":"variable","tokens":[{"end":51,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let block = body.basic_blocks.next_index();
context_before:     fn insert_none_ret_block(&self, body: &mut Body<'tcx>) -> BasicBlock {
context_after:         let source_info = SourceInfo::outermost(body.span);