syntax_data: {"ast_node_type":"variable","tokens":[{"end":74,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let closure_env_param = cx.closure_env_param(owner_def, owner_id);
context_before:     if let Some(fn_decl) = tcx.hir_fn_decl_by_hir_id(owner_id) {
context_after:         let explicit_params = cx.explicit_params(owner_id, fn_decl, &body);