syntax_data: {"ast_node_type":"other","tokens":[{"end":5,"kind":"keyword","start":0,"text":"{"}]}
source_snippet:     {
context_before:         F: FnOnce(&mut Builder<'a, 'tcx>) -> BlockAnd<()>,
context_after:         let scope = IfThenScope { region_scope, else_drops: DropTree::new() };