{"ast_node_type":"variable","tokens":[{"end":100,"kind":"keyword","start":0,"text":"if"}]}
                    if let ast::TyKind::Slice(inner_ty) | ast::TyKind::Array(inner_ty, _) = &ty.kind
                    // syntactically valid type after all.
                        && let ast::TyKind::Err(_) = inner_ty.kind