>>> I can't find any code out there that seems to care what is its default
>>> value (all users set it but doesn't look at it, AFAICT).
>>
>> This case looks problematic:
>>
>>                  ;; LANG can be nil.  We don't want to use the fallback
>>                  ;; in `treesit-language-at', so here we call
>>                  ;; `treesit-language-at-point-function' directly.
>>                  (let* ((lang (and treesit-language-at-point-function
>>                                    (funcall treesit-language-at-point-function
>>                                             pos)))
>
> Ah, indeed you're right.
>
>> But I believe this whole 'let*' can be replaced by just
>> the 'treesit-parsers-at' call.  I hope Yuan could confirm this.
>
> [ Not familiar enough with this code, so I'll let Yuan chime in.  ]

Yuan, please confirm whether the reference to 'treesit-language-at-point-function'
can be removed from 'treesit-node-at' this way: