Ok, opDot() is deprecated in version 2.082. However, if we simulate this situation with a function (opdot in our example), we get unexpected results.

struct Point { int x, y; }

struct S
{
    Point point;
    alias opdot this;

    auto opdot()
    { // opDot() is deprecated in v2.082
      //this.point = Point(100, 100);/* <-- also if you only use: s == Point(100, 101)
        point.x = 100;
        point.y = 100;
        point.x++;//*/

        return &point;
    }
}

void main()
{
    S s;
    s.x++; // as if this line doesn't exist!
    s.y++;

    //s.x++; //  <-- also if you use: s == Point(102, 100)
    assert(s.point == Point(101, 101));
}

SDB@79

On Wednesday, 28 September 2022 at 03:45:59 UTC, Salih Dincer wrote:

struct Point { int x, y; }

struct S
{
    Point point;
    alias opdot this;

    auto opdot()
    { // opDot() is deprecated in v2.082
      //this.point = Point(100, 100);/* <-- also if you only use: s == Point(100, 101)
        point.x = 100;
        point.y = 100;
        point.x++;//*/

        return &point;
    }
}

void main()
{
    S s;
    s.x++; // as if this line doesn't exist!
    s.y++;

    //s.x++; //  <-- also if you use: s == Point(102, 100)
    assert(s.point == Point(101, 101));
}

opdot is called two times so you reset the state of point members 100

struct Point { int x, y; }

struct S
{
    Point point;
    alias opdot this;

    Point* opdot() return
    {
        this.point.x = 100;
        this.point.y = 100;
        return &this.point;
    }
}

void main()
{
    S s;
    s.x += 1;
    assert(s.point == Point(101, 100));
    s.y += 1;
    assert(s.point == Point(100, 101));
}

On Wednesday, 28 September 2022 at 06:39:30 UTC, user1234 wrote:

struct Point { int x, y; }

struct S
{
    Point point;
    alias opdot this;

    auto opdot()
    { // opDot() is deprecated in v2.082
      //this.point = Point(100, 100);/* <-- also if you only use: s == Point(100, 101)
        point.x = 100;
        point.y = 100;
        point.x++;//*/

        return &point;
    }
}

void main()
{
    S s;
    s.x++; // as if this line doesn't exist!
    s.y++;

    //s.x++; //  <-- also if you use: s == Point(102, 100)
    assert(s.point == Point(101, 101));
}

struct Point { int x, y; }

struct S
{
    Point point;
    alias opdot this;

    Point* opdot() return
    {
        this.point.x = 100;
        this.point.y = 100;
        return &this.point;
    }
}

void main()
{
    S s;
    s.x += 1;
    assert(s.point == Point(101, 100));
    s.y += 1;
    assert(s.point == Point(100, 101));
}

I realize that maybe you are aware of what's happening, in which case you need to use opDispatch instead

struct Point { int x, y; }

struct S
{
    Point point;

    auto ref opDispatch(string member)() return
    {
        return __traits(getMember, point, member);
    }
}

void main()
{
    S s;
    s.x += 1;
    assert(s.point == Point(1, 0));
    s.y += 1;
    assert(s.point == Point(1, 1));
}

On Wednesday, 28 September 2022 at 06:39:30 UTC, user1234 wrote:

void main()
{
    S s;
    s.x++; /* In this line, it's x = y = 100 firstly, then x = 101 and 102. */
    s.y++; /* In this line, it's x = y = 100 again, then x = 101 and y = 101. */

   assert(s.point == Point(101, 101)); // That's ok...
}

Thank you...

It seems that I'm as sharp as a tack. 😀

SDB@79