...Length len = 2 * (r.upperLeft.y - r.lowerRight.y); // problem
    Length len = 0;
    len += 2...

...thousands(int(count) / divisor)

# len of the maximum count
ncols = max(len(count) for count...

...line[0]))
n = max(len(p1) for p1, p2 in parts) # len of the maximum...

...tupleof){
  static if(isNoLength!(typeof(m))){
    auto len = lenField!(rec2, typeof(m));
    ...
  }else{
    ...
  }
}

The other...

...pos = read(len,data);
    //else assume len has already been read
    params.length = len;
    ...
    // read...

...something like:

auto __len = arr.length;
for(uint __i = 0; __i < __len; ++__i)
{
   auto x...

...append" seems two instructions:
arr[arr_len] = j;
arr_len++;

And the C++ v1 too...

...uint arr_len = 0;

        foreach (j; 0 .. N) {
            arr[arr_len] = j;
            arr_len++;
        }

        printf...

...x_len = 0;

        foreach (j; 0 .. 5_000_000) {
            x[x_len] = j;
            x_len...

...if (len <= prime_list[i])
                    break;
            }
            len = prime_list[i];
            newb.b = new aaA*[len...