Re: Question: suppress ask-user-about-lock?

[Qiantan Hong]

> (info "(elisp)Threads") talks about `let' bindings being thread local.
> I always took that to apply to the other let-like bindings as well.  It
> looks like `cl-letf' uses `let*' under the hood.
For LETFing a symbol-function, it FSETs under the hood, which is not
safe. In fact it is impossible to do it using thread-safe let only,
because code outside of the CL-LETF calls the function from
the function cell, and to have your binding affect them the only
way is to set the thread-unsafe function cell.