Re: Make objects.opEquals a template?

[Yuxuan Shui via Digitalmars-d]

On Monday, 13 July 2015 at 09:10:41 UTC, ketmar wrote:
On Mon, 13 Jul 2015 06:49:09 +0000, Yuxuan Shui wrote:
The main reason here is to use '==' in @safe code:

class A {
        override @safe bool opEquals(Object o) {
                return cast(A)o !is null;
        }
}
@safe void main() {
        A a = new A;
        A b = new A;
        a == b;
}

This doesn't compile in current D, because objects.opEquals 
takes two Object, and Object.opEquals is not @safe.

Why can't we have a template objects.opEquals?

auto opEquals(T, S)(T a, S b) { ... }

'case templates can't be virtual functions, so the following 
will not work:

  bool cmp (Object a, Object b) { return a.opQeuals(b); }

  MyObj a, b;

  cmp(a, b);

What do you mean by virtual function? objects.opEquals is not a 
member function.