On Monday, 31 March 2014 at 15:51:03 UTC, Justin Whear wrote:
Trying to insult me isn't going to make you right, nor will an
appeal to
unicorns. With a well-defined order-of-operations, this might
be correct
behavior;
Actually, regardless of order of operation, specs says you still
get "i" un-incremented, since opEquals's lhs has no side effects
anyways.
...The only way to have some other result, is if there was some
sort of undefined behavior in the statement, at which point there
is no more concept of "correct behavior"
in this case I suspect D is like C and that this is undefined
behavior
Yup. It's undefined behavior. I replied too fast and missed it.
thus I would support making this statement illegal or at least
warning.
The issue is that the legality of this can't be checked at the
semantic phase.
It depends on *who* the left and right hand sides are. It's
obvious in "i = i++;", but if you start mixing function calls,
references and whatnot, the line becomes more blurry:
//----
int i;
auto p = &i;
*p = i++; //Legal? Illegal?
//----
So this means making it illegal is out of the question.
As for making it a warning, well, Walter is (AFAIK) pretty much
against having any warnings at all, short of straight up
deterministic semantic warnings "dangling else"/"deprecation".
