comparing pointers passed to and returned from funcs

[Steven Schveighoffer]

On Tue, 01 Mar 2011 18:11:00 -0500, bearophile <bearophileHUGS at lycos.com>  
wrote:

> http://d.puremagic.com/issues/show_bug.cgi?id=5678

I think there is a general bug where any time the compiler uses an enum,  
it simply replaces the expression declared for the enum.

So basically

enum TRUE = new DElement(true);

void main()
{
    auto delem1 = TRUE;
    auto delem2 = TRUE;
    assert(delem1 is delem2); // fails
}

gets morphed into this:

void main()
{
    auto delem1 = new Delement(true);
    auto delem2 = new Delement(true);
    assert(delem1 is delem2); // fails
}

Obviously this works great when the enum is a value type or a string  
literal (which is created at compile time).  However, it is not so great  
for things like AAs, array literals, objects, or structs.

I think there are a few of these bugs in bugzilla, and there should be at  
least a tracker, and if not, they should all be combined.  This is a  
serious problem in D, and really creates havoc (both performance-wise and  
semantically).  I don't anticipate there is an easy fix.

Essentially, I'd say enum is completely useless except for builtin types  
and strings.

-Steve