Generics and assigning variables

I'm afraid that this isn't possible because there is no way that the compiler can determine in advance that there will be an implicit conversion from both int and bool to T for any T that might be used to construct the generic method. Nor is there a suitable constraint that would ensure this.

If  I were you, I'd just code two non-generic overloads of the fill_array method, one that takes an int[] and the other a bool[] as its second parameter.

Incidentally, I assume you're wanting to allow for partial filling of the array, otherwise you could use array_out.Length instead of passing the 'count' parameter.