syntax_data: {"ast_node_type":"other","tokens":[{"end":37,"kind":"keyword","start":0,"text":"|region,"}]}
source_snippet:                         |region, _| {
context_before:                         tcx.assumed_wf_types(fn_def_id.expect_local()).to_vec(),
context_after:                             // If `region` is a `ReLateParam` that is captured by the