[Proposal]Conditional statement in with-expression

[rabbitism]

In order to decrease cloning cost when creating new record instance from existing one but whether property will be changed is based on different conditions, it'll be nice to support conditional statement in with-expression.

By doing this, it solved the problem of whether to assign a new value instead of which new value to assign

var person2 = person1 with {
    if(condition1){
        Name = name2,
    }
    if(condition2){
        Position = position2,
    }
}

This can be lowered to

Person person2 = person1.<Clone>$();
if(condition1){
    person2.Name = name2;
}
if(condition2){
    person2.Position = position2;
}

Current walk around:

var person2 = person1 with {
    Name = conditional1 ? name2 : person1.Name,
    Position = conditional2 ? position2 : person1.Position
}