> let place is an idea I’ve seen floating around

TXR Lisp (placelet)

https://www.nongnu.org/txr/txr-manpage.html#S-9A89A6B8

Emacs Lisp (gv-letplace)

https://www.gnu.org/software/emacs/manual/html_node/elisp/Ad...

Why new syntax? We could have:

   let &p = &x.field;

Or

   let &mut p = &mut x.field;

This feel suspiciously like the sendmail-fiction of postfix. I don't know if that is a good thing.

EDIT: Not really, but it still feels like adding unneeded