My understanding is that, as per spec, a += k is rewriten as :
a = cast(typeof(a)) (a + k);
Which make our example looks like :
a = cast(typeof(a)) (a + a++);
a = cast(typeof(a)) (a + { auto olda = a; a++; return olda; }());
The whole damn thing should end up with newa == 2 * olda . This
is what SDC does. DMD tells me newa == 2 * olda + 1, as it
evaluate a++ before that the value of a for the sum.
I though we decided to do everything LTR, but discussing with
Andrei, it seems that Walter oppose this in some special cases. I
think we should keep it consistent and do LTR all the way down.
Relevant bug report:
https://issues.dlang.org/show_bug.cgi?id=14364
