{"ast_node_type":"variable","tokens":[{"end":79,"kind":"keyword","start":0,"text":"let"}]}
                        let is_translatable = Self::is_diag_message(cx, arg_ty)
                        // Is the arg type `{Sub,D}iagMessage`or `impl Into<{Sub,D}iagMessage>`?
                            || matches!(arg_ty.kind(), ty::Param(arg_param) if arg_param.name == sig_param.name);