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

[Adam D. Ruppe via Digitalmars-d-learn]

On Saturday, 20 May 2017 at 10:48:54 UTC, Gary Willoughby wrote:
> 		// Why is this._foo null here???

The others have answered why and what to do, but note that 
according to the spec, that any struct should be able to have its 
destructor called, so you should do a null check in there anyway.