D Compile Time TCO

D Compile time TCO

import std.stdio;

double factorial (double i)
{
  if (i == 1) {
    return 1;
  }
  else {
    return (i * factorial(i - 1));
  }
}

void main()
{
  pragma(msg, factorial(1000));
}

$ dub build; ./factorial
Performing "debug" build using dmd for x86_64.
factorial ~master: building configuration "application"...
source/app.d(3,8): Error: function app.factorial CTFE recursion limit exceeded
source/app.d(9,26): called from here: factorial(i - 1.00000)
source/app.d(3,8): 1000 recursive calls to function factorial
source/app.d(15,24): called from here: factorial(1001.00)
source/app.d(15,3): while evaluating pragma(msg, factorial(1001.00))
dmd failed with exit code 1.