Re: template type deduction for non-dependent parameters

[Mark Mitchell <mark at codesourcery dot com>]

Geoffrey Keating wrote:

> The comment also said that infinite recursion could occur.  I think
> this is a left-over from when we used to fully instantiate templates,
> including generating code, without any queuing.  Now we delay all
> template instantiations until the end of compilation and we have
> unit-at-a-time mode.  The only infinite recursion I can see would be
> if the compiler tried to instantiate a conversion function in the call
> to can_convert_arg and somehow ended up back in this code again; but
> as far as I can see, that's impossible.

There can certainly be conversion functions that are templates, and thus 
would end up back in this code, but I'm not sure if you could get an 
infinite recursion this way.

> Bootstrapped & tested on powerpc-darwin.  I'll wait a while for comments
> before committing.

Have you run Plum-Hall on this?  I think you have access, and that if 
you do, you should run those tests as this is a very tricky area, and I 
don't fully trust my own knowledge or our testsuite to catch things. 
Once that's done, or if, contrary to my belief, you don't actually have 
Plum-Hall, then this is OK.

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304