typeof(this) opCall(U, V)(U x, V y) if (__traits(compiles, { this.x = 5; })) {
writeln("unstatic opCall");
this.Set(x, y);
return this;
}
static Vector2D!(T) opCall(U, V)(U x, V y) if
(!__traits(compiles, { this.x = 5; })) {
return new Vector2D!(T)(to!(T)(x), to!(T)(y));
}
