solve method Null safety

Implementation

static void solve(Matrix4 A, Vector4 x, Vector4 b) {
  final a00 = A._m4storage[0];
  final a01 = A._m4storage[1];
  final a02 = A._m4storage[2];
  final a03 = A._m4storage[3];
  final a10 = A._m4storage[4];
  final a11 = A._m4storage[5];
  final a12 = A._m4storage[6];
  final a13 = A._m4storage[7];
  final a20 = A._m4storage[8];
  final a21 = A._m4storage[9];
  final a22 = A._m4storage[10];
  final a23 = A._m4storage[11];
  final a30 = A._m4storage[12];
  final a31 = A._m4storage[13];
  final a32 = A._m4storage[14];
  final a33 = A._m4storage[15];
  final b00 = a00 * a11 - a01 * a10;
  final b01 = a00 * a12 - a02 * a10;
  final b02 = a00 * a13 - a03 * a10;
  final b03 = a01 * a12 - a02 * a11;
  final b04 = a01 * a13 - a03 * a11;
  final b05 = a02 * a13 - a03 * a12;
  final b06 = a20 * a31 - a21 * a30;
  final b07 = a20 * a32 - a22 * a30;
  final b08 = a20 * a33 - a23 * a30;
  final b09 = a21 * a32 - a22 * a31;
  final b10 = a21 * a33 - a23 * a31;
  final b11 = a22 * a33 - a23 * a32;

  final bX = b.storage[0];
  final bY = b.storage[1];
  final bZ = b.storage[2];
  final bW = b.storage[3];

  var det =
      b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06;

  if (det != 0.0) {
    det = 1.0 / det;
  }

  x
    ..x = det *
        ((a11 * b11 - a12 * b10 + a13 * b09) * bX -
            (a10 * b11 - a12 * b08 + a13 * b07) * bY +
            (a10 * b10 - a11 * b08 + a13 * b06) * bZ -
            (a10 * b09 - a11 * b07 + a12 * b06) * bW)
    ..y = det *
        -((a01 * b11 - a02 * b10 + a03 * b09) * bX -
            (a00 * b11 - a02 * b08 + a03 * b07) * bY +
            (a00 * b10 - a01 * b08 + a03 * b06) * bZ -
            (a00 * b09 - a01 * b07 + a02 * b06) * bW)
    ..z = det *
        ((a31 * b05 - a32 * b04 + a33 * b03) * bX -
            (a30 * b05 - a32 * b02 + a33 * b01) * bY +
            (a30 * b04 - a31 * b02 + a33 * b00) * bZ -
            (a30 * b03 - a31 * b01 + a32 * b00) * bW)
    ..w = det *
        -((a21 * b05 - a22 * b04 + a23 * b03) * bX -
            (a20 * b05 - a22 * b02 + a23 * b01) * bY +
            (a20 * b04 - a21 * b02 + a23 * b00) * bZ -
            (a20 * b03 - a21 * b01 + a22 * b00) * bW);
}