Is it possible to run this code in compile-time?

import std.stdio, std.functional;

ulong fact(ulong n)
{
        alias mfact = memoize!fact;
        return n < 2 ? 1 : n * mfact(n - 1);
}

void main() {

        writeln(fact(10));
}

In CommonLisp variable *factorial-cache* available in CT, and RT. Moreover, in the compiler environment of your *factorial-cache* and RT. Thus we memoires as calculations in CT (constants), and RT.

(eval-always
  (defparameter *factorial-cache* (make-hash-table))
  (defun factorial (n)
    (if (< n 1)
        1
(setf (gethash n *factorial-cache*) (* n (factorial (1- n)))))))

(define-compiler-macro factorial (&whole whole n)
  (if (constantp n) (factorial n) whole))

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