Re: [Sbcl-bugs] 2.5.11: SB-WALKER:MACROEXPAND-ALL may expose special form SB-C::WITH-SOURCE-FORM

It's a macro that expands to PROGN. No code walkers should get confused.

On Sun, Dec 7, 2025 at 3:18 PM Bohong Huang via Sbcl-bugs
<[email protected]> wrote:
>
> Hello SBCL developers,
>
> In the latest 2.5.11 version, I found that my `cffi-ops` (a code
> walker-based library that provides convenience for writing CFFI code) is
> broken because it relys on MACROEXPAND-ALL.
>
> Consider the following code:
>
>
> (defmacro a ()
>   '(+ 1 1))
>
> (defmacro b ()
>   (print
>    (sb-walker:macroexpand-all
>     '(typecase 0
>       (fixnum (a))))))
>
> (defun main ()
>   (b))
>
>
> When compiling (MAIN), the printed result is:
>
>
> (IF (SB-C::WITH-SOURCE-FORM (FIXNUM (A)) (TYPEP 0 'FIXNUM))
>     (+ 1 1)
>     NIL)
>
>
> This exposes the non-portable special form SB-C::WITH-SOURCE-FORM, which
> may confuse some custom code walkers because they don't know which part
> is the real code - for example, they might mistakenly treat illegal
> expressions like (FIXNUM (A)) as the code, leading to other problems.
>
> It can be confirmed that this issue does not exist in version 2.5.10.
>
> Thanks in advance for your time. Any thoughts on this issue? Looking
> forward to your reply.
>
> Best regards,
> Bohong Huang
>
>
>
> _______________________________________________
> Sbcl-bugs mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/sbcl-bugs


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