Re: Why would an initialised struct pointer field be null in the struct's destructor?

[Moritz Maxeiner via Digitalmars-d-learn]

On Saturday, 20 May 2017 at 10:48:54 UTC, Gary Willoughby wrote:
In the following code, the `_foo` pointer (of the Foo struct) 
is null in the first call to the destructor. Why is this? I 
think it's got something to do with the foreach loop but I'm 
not sure. Any ideas?

struct Bar
{
        private Foo[] _data;

        public this(int n)
        {
                this._data = (cast(Foo*) calloc(n, Foo.sizeof))[0 .. n];

                foreach(ref element; this._data)
                {
                        auto tmp = Foo(1);
                        element = tmp;
                }
        }
}

Because `element = tmp` destroys `element`, which you allocated 
filled with zeroes.
The destructor will run for each `element`.