syntax_data: {"ast_node_type":"variable","tokens":[{"end":74,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let breakable_scope = self.scopes.breakable_scopes.pop().unwrap();
context_before:         let normal_exit_block = f(self);
context_after:         assert!(breakable_scope.region_scope == region_scope);