Re: Why is the struct instance being copied here?

[Steven Schveighoffer]

On Fri, 11 Mar 2011 04:50:38 -0500, d coder <dlang.co...@gmail.com> wrote:
Greetings

Please look at the code down here. When compiled and run, I get the  
message
"Call to postblit" printed. I think it is because of the foreach block,
because the variable "i" is not declared as ref there. Is there a way to
make it a ref?

Regards
- Puneet

import std.stdio;

struct Foo {
  this(this) {
    writeln("Call to postblit");
  }
}

class Bar {
  Foo foo;
  this() {
    foreach(i, f; this.tupleof) {
      // do nothing
    }
  }
}

void main()
{
  Bar bar = new Bar();
}

This typically works in a foreach loop:

foreach(i, ref f; x)

but a foreach for a tuple is a special beast, and using ref in your code  
yields this error:

foreachtuple.d(12): Error: no storage class for value f

But I agree it should be doable.  This should qualify for an enhancement  
request: http://d.puremagic.com/issues/enter_bug.cgi?product=D

-Steve