Order of evaluation - aka hidden undefined behaviours.

[monarch_dodra]

On Tuesday, 25 September 2012 at 22:58:11 UTC, Iain Buclaw wrote:
> Pop quiz!
>
> Without cheating, I invite people to have a good guess what 
> 'abc' is equal to, but just to narrow it down.
>
> 1)  It isn't "ABC".
> 2)  On x86/x86_64, it isn't "ACB".
> 3)  On everything else, it's the reverse of what you'd expect 
> on x86/x86_64.

I'd say abc's value is "unspecified", and any attempt at 
predicting it would be bogus. That's my answer anyways

> The problem here is that the array operation A[] = B[] + C[] 
> gets transformed into an extern(C) call.  And because there's 
> no strict rules in place over the order of which it's 
> parameters are evaluated, it could go either way (LTR, or RTL).

I don't see how the "extern(C)" is involved here, since it is the 
D compiler that first evaluates A(), B() and C() before passing 
the making the C function call. Or did I miss something?