the point is to avoid breaking code.
I don't think you can simultaneously try to not-suggest deprecating cast() shortcuts, and do-suggest there's no need to extend the language as it can be done in library code, while suggestiing duplicating cast() shortcuts. Your point would make sense if you were trying to get rid of the shortcuts. Otherwise you should argue for signed(x) / unsigned(x)not suggesting deprecating cast(), just suggesting there's no need to
extend the language as it can be done in library code, advantageously. It's
trivially extensible as I wrote it. However, any language extension has to
be re-implemented by each compiler implementation.
Make it consistent.