bug#67239: 30.0.50; 30.0.50: Error in nativecomp

[Eli Zaretskii <eliz@gnu.org>]

> From: Imran Khan <contact@imrankhan.live>
> Date: Fri, 17 Nov 2023 19:13:46 +0600
> 
> 
> Hello, I have come across a function that gives error when native
> compiled, but works fine when byte compiled.  The issue arose when using
> a third-party library (ts-format function in ts.el):
> 
> https://github.com/alphapapa/ts.el/blob/master/ts.el
> 
> But I have curved out the code so that you hopefully don't need to
> install that.
> 
> Reproduction under `emacs -Q`:
> 
> 1. First library "my-time.el" looks like:
> 
> ```
> ;;; -*- lexical-binding: t; -*-
> 
> (require 'cl-lib)
> 
> (cl-defstruct time
>   unix)
> 
> (defvar time-default-format "%Y-%m-%d %H:%M:%S %z"
>   "Default format for `time-format'.")
> 
> (defsubst time-format (&optional time-or-format-string time)
>   "Format timestamp with `format-time-string'.
> If TS-OR-FORMAT-STRING is a timestamp or nil, use the value of
> `time-default-format'.  If both TS-OR-FORMAT-STRING and TS are nil,
> use the current time."
>   (cl-etypecase time-or-format-string
>     (time (format-time-string time-default-format (time-unix time-or-format-string)))
>     (string (cl-etypecase time
>               (time (format-time-string time-or-format-string (time-unix time)))
>               (null (format-time-string time-or-format-string))))
>     (null (cl-etypecase time
>             (time (format-time-string time-default-format (time-unix time)))
>             (null (format-time-string time-default-format))))))
> 
> (provide 'my-time)
> ```
> 
> 2. Then there is my code "my-bug.el":
> 
> ```
> ;;; -*- lexical-binding: t -*-
> 
> (require 'my-time)
> 
> (defun my-bug ()
>   (let ((time (make-time :unix (time-convert (current-time) 'integer))))
>     ;; (message (time-format time)) ;; one argument works fine
>     (message (time-format "%F" time)) ;; but this says: (wrong-type-argument stringp time)
>     ))
> 
> (provide 'my-bug)
> ```
> 
> 3. When both of these are native compiled, doing `M-: (my-bug)` gives:
> ```
> Debugger entered--Lisp error: (wrong-type-argument stringp time)
>   my-bug()
>   eval-expression((my-bug) nil nil 127)
>   funcall-interactively(eval-expression (my-bug) nil nil 127)
>   command-execute(eval-expression)
> ```
> 
> 4. But if I C-M-x on `my-bug` manually, it works fine.
> 
> As far as I can tell, under 29.1 it worked fine under nativecomp too.

Adding Andrea to the discussion.