syntax_data: {"ast_node_type":"variable","tokens":[{"end":57,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let owner_id = tcx.local_def_id_to_hir_id(owner_def);
context_before:     // Lower the params before the body's expression so errors from params are shown first.
context_after:     if let Some(fn_decl) = tcx.hir_fn_decl_by_hir_id(owner_id) {