Re: const(X) member of Y

[Maxim Fomin]

On Wednesday, 6 February 2013 at 18:15:53 UTC, Dan wrote:

This workaround succeeds, but, based on this thread 
(http://forum.dlang.org/thread/ywispsasaylqscyua...@forum.dlang.org) 
I don't know if it is a bug or not. If it is not a bug, I would 
doubt it is the prescribed approach for doing this?

Thanks,
Dan

Huh, ability to call non-const postblit from const __postblit is 
actually a general problem of a major type system breakage:

import std.stdio;

struct S
{
    int i;
    void bar()
    {
        ++i;
    }
    void foo() immutable
    {
        //#1
        //bar(); //error
        //(&bar)(); //works, lang hole

        //#2
        void delegate() dg1 = &bar; //works, lang hole
        //dg1(); //

        //#3
        void delegate() dg2;
        //dg.ptr = this; //error
        dg2.ptr = cast(void*)&this;
        //dg.funcptr = &S.bar; //error
        dg2.funcptr = cast(void function())&S.bar;
        dg2(); //works due to cast
    }
}

void main()
{
    immutable S s;
    writeln(s.i);
    s.foo();
    writeln(s.i);
}

The fact that bar() does not work and (&bar)() works is terrific. 
Also, if dg1 call is uncommented, dmd wrongly generates 
instruction which leads to segfault.