Can I use memoize with a non-static struct method?

[Marc via Digitalmars-d-learn]

something like this:

struct S {
  // variables...
  string doGen(int n) { return ""; }
  alias gen = memoize!doGen;
}

The error I got is:

Error: need 'this' for 'doGen' of type 'string(int n)'

I can't make doGen static because it access non-static struct 
members... can I workaround this?