opAssign and const?

[Era Scarecrow]

On Saturday, 5 May 2012 at 04:15:21 UTC, Jonathan M Davis wrote:
> On Saturday, May 05, 2012 05:50:26 Era Scarecrow wrote:
>> > On Saturday, 5 May 2012 at 03:32:06 UTC, Jonathan M Davis 
>> > wrote:
>> >> ---------
>> >> Func­tions are over­loaded based on how well the 
>> >> ar­gu­ments to a func­tion can match up with the 
>> >> pa­ra­me­ters. The func­tion with the  best match is 
>> >> se­lected. The lev­els of match­ing are:
>> >> 
>> >> 1. no match
>> >> 2. match with im­plicit con­ver­sions
>> >> 3. match with con­ver­sion to const
>> >> 4. exact match
>> >> ---------
>> 
>> Hmm maybe it should have a preference for Lvalue vs Rvalue... 
>> So... Walter or Andrei?
>> 
>>   1. no match
>>   2. match with im­plicit con­ver­sions (Lvalue required)
>>   3. match with con­ver­sion to const (Lvalue required)
>>   4. match with im­plicit con­ver­sions
>>   5. match with con­ver­sion to const
>>   6. exact match
>
> This will likely be _very_ relevant to the proposed changes  
> which make ref and const ref work with rvalues (the details on 
> that are still  being sorted out, I believe). However, I don't 
> believe that either Walter or Andrei  pays attention to 
> D.Learn, so if you want to bring it up for discussion, post  
> about it in the main newsgroup (not to mention, your post is 
> buried enough in  this thread that many who _do_ pay attention 
> to D.Learn wouldn't see it).

  This is a topic pulled from D.learn.
  
http://forum.dlang.org/thread/qyzvvlirbcklwjealnaa@forum.dlang.org

  Quick brief overview: While trying to use opAssign to copy data 
(and keep arrays separate), one opAssign is being selected over 
the other. The first is for a reference (ref X) which does a 
buffer[] = rhs.buffer[] copy, while (X) for the temporaries the 
array is passed over, as buffer = rhs.buffer

  When adding changing (ref X) to (ref const X), it is calling the 
(X) which breaks my array separation when (ref const X) should 
work fine. (Afterall I'm promising not to change the data, not 
requiring it to be const).