Re: std.typecons.Proxy + inheritance breaks cast'ing to inherited type

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On Tuesday, 17 March 2015 at 05:32:49 UTC, Ali Çehreli wrote:
On 03/16/2015 04:59 PM, Lukasz Wrzosek wrote:
Bug reported as
https://issues.dlang.org/show_bug.cgi?id=14298

Thanks...

I have carried the discussion over to the main newsgroup:

  http://forum.dlang.org/thread/me8e0a$1kp6$1...@digitalmars.com

As I mention there, there is a workaround: Add a catch-all 
opCast to the class in question, which can simply forward to 
the all-powerful std.conv.to:

    T opCast(T)()
    {
        import std.conv;
        return this.to!T;
    }

Now it compiles and works as expected.

Ali

That will throw an exception if the conversion can't be done 
instead of just returning null, won't it? Why can't you do this 
instead?

t opCast(t)()
if (is(typeof(cast(T)this)))
{
    return cast(T)this;
}