Please be more careful when changing the language behavior

[mw]

On Wednesday, 3 June 2020 at 19:40:10 UTC, jmh530 wrote:
> On Tuesday, 2 June 2020 at 06:17:50 UTC, mw wrote:
>> [snip]
>
> Thanks for that some interesting materials there about Eiffel.
>
> As it says on the wikipedia page, the select & rename together 
> drives their solution. Combining select and rename in one class 
> is like an alias in D. However, D does not have the ability to 
> prevent calling a member function of an inherited class. Using 
> opDispatch doesn't work because it comes after calling member 
> functions.
>
> I think the most D-like way to incorporate this behavior is to 
> allow @disable in a derived class for a base member function. 
> Right now (see code below), you get a message about a 
> depreciation (I think this one [1]) and not being able to 
> @disable an overridden (you have to throw in an override) base 
> class member function.
>
> Probably would require a DIP, there is likely code out there 
> that depends on always being able to call the base class member 
> functions. Ideally, it would also handle base members, but this 
> would likely require an even bigger change.
>
> [1] 
> https://dlang.org/deprecate.html#Overriding%20without%20override
>
>
> import std.stdio: writeln;
>
> class A
> {
>     int x;
>     void foo(int x){
>     	writeln("A");
>     }
> }
>
> class B : A
> {
>     alias val = A.foo;
>
>     //@disable this.x;
>     @disable override void foo(int){}
> }
>
> void main() {
>     A a = new A;
>     B b = new B;
>     b.val(1);
> }


This is a bit off-topic in this thread, I started a new one:

https://forum.dlang.org/thread/obqthozmxwzhvrafothw@forum.dlang.org


will discuss the topic there.