syntax_data: {"ast_node_type":"variable","tokens":[{"end":46,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:     if let Some(m) = pcx.rust_2024_migration {
context_before:     debug!("pat_from_hir({:?}) = {:?}", pat, result);
context_after:         m.emit(tcx, pat.hir_id);