Re: C++0x: unfortunate interaction of rvalue references and concepts
on Sat Dec 06 2008, SG <s.gesemann-AT-gmail.com> wrote:
Hi!
I noticed some unfortunate gotchas when using both features (rvalue
references and concepts/templates) which I'm going to mention here.
Most importantly: The current spec draft seems to contain such a bug
in the way std::vector (and possibly other containers as well) are
defined:
in 23.2.6 (page 826 of N2798.pdf) we have
requires AllocatableElement<Alloc, T, const T&>
void push_back(const T& x);
requires AllocatableElement<Alloc, T, T &&>
void push_back(T&& x);
The problem is: rvalue references are allowed to bind to lvalues.
Yes, that's the problem. Doug Gregor and I have submitted a committee
paper to correct it. See
http://www.boostpro.com/writing/n2812_08-0322_soundness.html
--
Dave Abrahams
BoostPro Computing
http://www.boostpro.com
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