new concept checks and the 3.0 ABI

[Jason Merrill]

>>>>> "Benjamin" == Benjamin Kosnik <bkoz@redhat.com> writes:

> There's a difference between what is being attempted with the C++ ABI and 
> the C++ API. Nobody is expecting the C++ API (libstdc++) to be in a 
> completely finished state for the 3.0 release.

It's not an API question; the C++ library API is specified by the standard.

What I think Joe is asking about is the libstdc++ ABI; in other words,
should people be able to expect that STL-using code compiled with 3.0 will
link with code compiled with 3.1?  In other words, should we commit
ourselves to making only representation-compatible changes?  Mark has
expressed the opinion that we should.  I'm ambivalent.

Jason