bug#67455: (Record source position, etc., in doc strings, and use this in *Help* and backtraces.)

[Stefan Monnier]

> OK, so it seems like I'll need a new pcase arm in macroexp--expand-all,
> and this new code will need to handle (function (cons 'lambda ...)), and
> the like.

If macroexp--expand-all receives code of the form

    (function (cons 'lambda ...))

it means it received broken code.
IOW, such an arm will never do anything useful (the best it can do is
emit a warning).

I suspect what you're looking for is yet different.


        Stefan