Please help with GC exception!

[Steven Schveighoffer]

On Wed, 09 May 2012 11:28:30 -0400, Gor Gyolchanyan  
<gor.f.gyolchanyan at gmail.com> wrote:

> I have a structure:
>
> private struct Block
> {
> 	this(size_t n) { /* allocate n bytes with GC.malloc */ }
> 	this(this) { /* deep-copy the bytes */ }
> 	~this() { /* deallocate them with GC.free */ }
> }
>
> And a class:
>
> final class Region
> {
> 	private Block _block;
> 	alias _block this;
> }
>
>
> This setup allows me to have memory regions, reallocation of which
> will never invalidate pointers, because thanks to Region class no-one
> holds a direct pointer to the memory.
> The problem is, that I get a
> core.exception.InvalidMemoryOperationError when my program ends.
>
> shared static ~this() { import core.thread;
> Thread.sleep(dur!`seconds`(1)); } // The error message still showed up
> after a delay, so it had to be at the process termination
> When I delete the Region object with "clear", the error diappears.
> Disabling the GC or forcing a collection before the 1-second sleep
> doesn't do anything: I still get the error after the 1-second sleep.
> The only way to stop the error, besides manually deleting the object
> is the remove the deallocation from the Block's destructor.
>
> Can somebody please help me fix this problem?

Yes, you cannot use GC.delete on a member of a class.  Ever.  The reason  
is, the memory you are attempting to delete may already be gone, there is  
no guaranteed order of destruction in a collection cycle.

-Steve