Stefan Monnier <monnier@iro.umontreal.ca> writes:

> > Ok, so let's be brave and aim to add it as `lazy-let' to subr-x.
> > There is a question I want us to think about: what should the semantics
> > of a `lazy-let' bound variable be if it is bound or set inside the
> > BODY?
>
> The semantics of `setq`ing such a var should be: compile-time error.
> The semantics of let-rebinding such a variable should be for the new
> binding to hide the outer (lazy) one.

Is this patch acceptable (also attached as file)?