If you could make any changes to D, what would they look like?

[H. S. Teoh]

On Mon, Oct 25, 2021 at 06:06:27PM +0000, Paul Backus via Digitalmars-d wrote:
> On Monday, 25 October 2021 at 17:45:22 UTC, H. S. Teoh wrote:
> > I suspect part of this problem is caused by the lame specialcased
> > behaviour of template instantiation errors being ignored when it's
> > opDispatch.  It's D's version of C++'s SFINAE, which leads to all
> > sorts of stupidity like a typo inside opDispatch suddenly causing a
> > dispatched member to disappear from existence 'cos the compiler
> > swallows the error and pretends the member simply doesn't exist.  So
> > if you're introspecting the member, the introspection code doesn't
> > even see it.  Which leads to hours of head-scratching over "I
> > obviously declared the darned member, why does the code NOT see
> > it?!?!".
[...]
> It's actually worse than that. Errors inside `opDispatch` are gagged
> and cause member lookup to fail...*unless* they're nested inside
> *another* template, in which case member lookup will succeed, and you
> will only get the error when you try to actually access the member:
[...]
> It's special cases inside of special cases--a complete mess.

=-O

Wow, that's totally messed up. :-/  Yeah, if there's any way to fix this
without breaking existing code, I'd love to push for this change in the
language.  Not holding my breath for it, though, unfortunately.


T

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