On Tuesday, 29 October 2013 at 11:46:53 UTC, Rene Zwanenburg
wrote:
On Monday, 28 October 2013 at 19:30:12 UTC, Maxim Fomin wrote:
Here is my attempt:
import std.stdio;
struct S
{
int i;
this(int i) { writefln("ctor, %X", i); this.i = i; }
this(this) { writefln("postblit, %X, %X", &this, i); }
~this() { writefln("dtor, %X, %X", &this, i); }
}
auto foo()
{
S s = S(1);
return { s = S(2); } ;
}
void main()
{
foo()();
}
ctor, 1
dtor, 7FFFF7ED8FF8, 1
ctor, 2
dtor, 7FFFFFFFDB30, 1
Inside foo() function object 's' is destroyed twice: first
time as a regular struct at the end of block scope, second
time before assigning S(2).
There are other tools: union bug, control flow tricks,
__traits, __dtor but they are move obvious.
That's pretty nasty :). But I suspect this is a bug and not by
design. __dtor and __traits are, IMHO, the proverbial escape
hatch D should provide, so I think that's OK. I take it that by
control flow trick you mean the try/catch example in your other
post?
Anyway, thanks for pointing this out. Will probably save me
some debugging in the future.
The combination of closure variables + scoped destruction should
be rejected, but currently it isn't. It's a compiler bug.
http://d.puremagic.com/issues/show_bug.cgi?id=11382
Kenji Hara
