Dynamic array leak?

[bitwise via Digitalmars-d]

On Saturday, 12 August 2017 at 08:16:56 UTC, Temtaime wrote:
>
> Collect - is a hint to the GC, not an order. It can ignore this 
> request.

If this is the case, then D's GC should have an option to force 
collection like C#'s GC:
https://msdn.microsoft.com/en-us/library/bb495757(v=vs.110).aspx

> Also do not rely on the gc calling a dtor - it is not safe and 
> can be called totally randomed, so use RC instead or expicit 
> destroy()

RC is not applicable. I'm doing unit tests for a non-GC container 
and trying to make sure all destructors are called properly.

Example:

unittest {
     auto a = List!int([S(0), S(1), S(2)]);
     a.popBack();
     assert(equal(a[], [S(0), S(1)]));
}

// lots of similar unittests

unittest {
     import std.stdio;
     GC.collect();
     assert(S.count == 0);
}

So if all goes well, S.count should be zero, but the arrays I'm 
testing against are being allocated on the heap. Given the 
conditions of the tests, it seems like GC.collect should be able 
to reclaim those arrays after the unit tests have exited, and in 
most cases does.

The ideal solution though, would be to allocate those arrays on 
the stack and avoid the problem altogether. There doesn't seem to 
be any reasonable way to do it though.

// won't this allocate anyways?
S[2] b = [S(0), S(1)];
assert(equal(a[], b[]));

// why can't I just declare a static array inline?
assert(equal(a[], int[2]{ S(0), S(1) }));