On Friday, 26 June 2020 at 13:21:25 UTC, drathier wrote:
How can I tell the compiler that I will never create a value of type X, while still being able to write code that uses it? Using void as a template parameter is where I started, but I still need to be able to declare variables inside this unreachable function, like `T foo;` even when `T == void`. Can I get any closer to what I want than an empty struct?
Depends on what you care about, I guess. A final abstract class has been my go-to on a few occasions. I'd argue the empty struct is better in most cases, and a forward-declared struct with no implementation might work in some cases.
-- Simen
