RE: Change of Lisp syntax for "fancy" quotes in Emacs 27?

[Drew Adams]

> > This is a judgment call, but we should _let Lisp judge_
> > about syntax errors, based on, well, its own syntax. If you
> > use (let (foo  foo)...), where there is a no-break space
> > between foo and foo, so be it. That's a single symbol,
> > `foo foo'.
> 
> Do we even allow the syntax (let ((foo))...)?  If we do, then why?
> There's (let (foo)...) and (let ((foo nil))...) for binding a symbol to
> nil.

Yes, sorry. I wasn't paying attention to the parens in that
example.

My point was only that use of `foo foo' (with a no-break
space between the two foo's) as a mistake/typo for an
intended `foo foo' (with a normal space) should not be
signaled by Lisp as an error. But the no-break space could
be highlighted as sometimes helpful info. `foo foo' (with
no-break space) is just a symbol, for Lisp - not a syntax
error.

E.g. (changing the example):

(let (foo foo)...) binds symbol `foo foo' (with a no-break
space) to nil. It doesn't bind symbol `foo' to the current
value of symbol `foo'.

So, e.g., if symbol `foo' happens to be unbound then
even evaluation of that binding won't raise an error
(e.g. unbound variable `foo').