It would seem to me to be a matter of program design, and programmer discretion, rather than a "subset of the language". Re: C++, we are saying "Don't use at least these dozen features, because they don't work well at many cooks scale, and/or they combine in ways which are non-orthogonal. We don't want you to use them because they complect[0] the code." Re: no panic Rust, we are saying "Don't call panic!(), because obviously you want a different program behavior in this context." These are different things.
> Isn't "Rust without panics" a subset of Rust?
I'm not sure there is much in your formulation.
It would seem to me to be a matter of program design, and programmer discretion, rather than a "subset of the language". Re: C++, we are saying "Don't use at least these dozen features, because they don't work well at many cooks scale, and/or they combine in ways which are non-orthogonal. We don't want you to use them because they complect[0] the code." Re: no panic Rust, we are saying "Don't call panic!(), because obviously you want a different program behavior in this context." These are different things.
[0]: https://www.youtube.com/watch?v=SxdOUGdseq4