Extended Description

My command line is clang++ -std=c++17 code0.cpp

The code is as follow:

template<typename... Args>
void spurious(Args... args)
{
(... + args).member;
}

int main()
{
}

The error message is:

code0.cpp:4:14: error: expected ';' after expression
(... + args).member;
^
;
code0.cpp:4:14: error: expected expression
2 errors generated.

Another similar code sample is as follow:

template <typename... Args>
int
foo (Args... args)
{
return (... + args).member;
}

struct S { int member; } s = { 0 };

int
main ()
{
return foo (s);
}

Again, clang++ rejects it, but g++ accept it.

Are the above two code samples legal code?