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Re: generalized lvalues -- patch outline
On Thu, Nov 25, 2004 at 01:06:42PM -0800, Matt Austern wrote:
[ cast-as-lvalue extension ]
> I changed my mind, and reluctantly agreed that immediate removal was
> the best option, because of what Joe Buck pointed out: that this wasn't
> a pure extension, but that it actually changed the meaning of legal C++
> programs by causing them to select the wrong overload in some cases.
> This was a serious bug. Seen in that light, removal seemed like the
> only possible answer: obviously we have to fix bugs.
There is another possible answer if it is decided that some limited form
of cast-as-lvalue must be kept (presumably under the control of some
option, or maybe just for Objective-C++): casts can be considered to be
non-lvalues for the purpose of overload resolution, unless there is no
match (at which point it can be considered an lvalue so that the
appropriate operator= or operator++ can be looked up). This would turn
the extension back into a pure extension, at the cost of kludging up the
front end.