> Uh, why not? Is there a particular reason why it's important to allow omitting the comma specifically here?
Because this is an abbreviated variadic function template.
If f(auto... x) is a variadic function template, removing x should
result in a function template with the same type. This is the case in
the current draft, it's totally fine, I'm happy with it, and I'm not
deprecating it.
Hmm, did you misread the line? It was this:
void f(auto x ...) // deprecated, equivalent to f(auto,...)
This is not an abbreviated variadic template; it's an abbreviated non-variadic template with an ellipsis parameter.
void f(auto... xs); // is a parameter pack
void f(auto xs...); // is an ellipsis parameter without comma, and I (and apparently Barry :)) want it deprecated plz
There's no reason for anyone to write
void f(auto xs...);
intentionally. Those programmers whose intention matches the compiler's interpretation (hopefully very rare) should instead write
void f(auto xs, ...);
to be explicit about their intentions. Meanwhile, the vast majority of programmers who write it by accident should be safely guided by compiler diagnostics toward what they actually meant, which is highly likely to be:
–Arthur