[PATCH] Improve error reporting for SFINAE

[Richard Smith]

On Mon, Apr 6, 2015 at 2:08 PM, Paul Fultz II <pfultz2 at yahoo.com> wrote:

> > gives the user no idea of how we got from a call to f into a call to g.
>
> For the default case, its better to show the first and last in the trace,
> as most users don't care about the intermediate steps.
>
> > If we produced a stack of 'in instantiation of' notes, this would be fine
>
> Yes, the full back trace can be added in the future(perhaps as a compiler
> flag). This is the first step towards that direction. There needs to be
> some refactoring to `DeductionFailureInfo` so it stores the entire
> diagnostics(rather than a single diagnostic) to make a full back trace
> possible.


The difference is, the current diagnostics allow the user to figure out
what happened. This change does not -- there's no way to find out which 'f'
caused the problem, and how we got from 'f' to 'g'. Hence this patch is not
acceptable as-is -- not even as a stepping stone to something better.

> note that's exactly what my patch in comment#1/comment#2 of that bug does
>
> That seemed to be more of a hack then something to be used in production.


Yes, absolutely, that change is not production-ready.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20150406/cb297bd3/attachment.html>