[tialaramex]

The main complaint in the post is basically that Rust's actual bona fide slice type doesn't work the way cobbled together library types for this purpose in C or C++ do.

The C++ type discussed is much newer than Rust (std::span was standardized in C++ 20).

Yes in many cases what C++ APIs mean here isn't a slice of zero Ts at all but instead None, and Rust has an appropriate type for that Option<&[T]> which works as expected, and so in many cases where people have built an API which they think is &[T] and are trying to make it with the unsafe functions mentioned it's actually Option<&[T]> they needed anyway, they don't even have a type correct design.

[swiftcoder]

I'm guess I'm inclined to go the other way. I tend to object to wrapping arrays in Option, because while semantically similar, the empty slice supports the full set of array APIs, whereas Option requires unwrapping

[tialaramex]

But that's not (a reference to) an array, that would be [T; N] it's a reference to a slice hence the syntax [T]

Arrays know their size, so the "I'll interpret it as zero Ts" makes even less sense for an array where we know up front the size as it is part of the type.