syntax_data: {"ast_node_type":"variable","tokens":[{"end":96,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let is_cleanup = self.body.basic_blocks_mut()[BasicBlock::from_usize(i)].is_cleanup;
context_before:         for (i, block_def) in block_defs.iter().enumerate() {
context_after:             let block = self.parse_block_def(self.statement_as_expr(*block_def)?, is_cleanup)?;