https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91974
--- Comment #2 from Barry Revzin <barry.revzin at gmail dot com> --- C++17 does change this rule. expr.call/8: The postfix-expression is sequenced before each expression in the expression-list and any default argument. The initialization of a parameter, including every associated value computation and side effect, is indeterminately sequenced with respect to that of any other parameter.
