syntax_data: {"ast_node_type":"other","tokens":[{"end":47,"kind":"keyword","start":0,"text":"region_scope_tree:"}]}
source_snippet:     region_scope_tree: &'tcx region::ScopeTree,
context_before:     infcx: InferCtxt<'tcx>,
context_after:     param_env: ty::ParamEnv<'tcx>,