I write code.
Err, sorry, didn't mean to close it.
Unbounded structs are also useful in Helios for some EFI stuff. I make use of the subtyping thing there to put them on the stack, too.
We're just endlessly discussing the consequences of the fact that we chose not to implement generics. We made this choice a long time ago and the trade-offs are well understood. It's not happening.
I don't find this problem particularly compelling. It affects one API in the whole of the stdlib. It's a known limitation of Hare's type system as-designed.
Would you want such a linter to be a separate program from the build driver?
Not sure whether or not the linter should be officially supported upstream. I think the best approach is to begin it as a downstream project, and it can be upstreamed later if that turns out to be a good idea.