alias this and struct allocation

[faissaloo via Digitalmars-d-learn]

I've been having some memory issues (referenced objects turning 
to nulls for no apparent reason) and I was wondering if I've 
misunderstood how allocation works when instantiating a struct 
that uses alias this:

        import std.stdio;
        
        struct Parent {
                int a;
        }
        struct Child {
                Parent base;
                alias base this;
                int y;
        }
        auto myStructMaker() {
                return new Child(Parent(10),20);
        }
        
        void main()
        {
                writeln(*myStructMaker());
        }
In this example is the data in base guaranteed to exist? Or is 
base definitely part of the allocation of Child on the heap?