https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122772
--- Comment #2 from Halalaluyafail3 <luigighiron at gmail dot com> ---
(In reply to Richard Biener from comment #1)
> The C frontend also rejects this:
>
> t.c: In function ‘main’:
> t.c:3:12: error: lvalue required as left operand of assignment
> 3 | (x.x=0)+=0;
> | ^~
>
> I think this is correct, an assignment produces an rvalue, not an lvalue.
>
> int main(){
> int a, b;
> (a = b) = 0;
> }
>
> is invalid.
Yes, in C assignment operators and comma operators never result in lvalues. In
C++ non-overloaded assignment operators will always result in an lvalue, and
non-overloaded comma operators will result in an lvalue if the second operand
is an lvalue. So this should be rejected in C and accepted in C++.
