Re: xref in GNU ELPA broken on Emacs 26

[Stefan Monnier]

> -(cl-defstruct (xref-item
> -               (:constructor xref-make (summary location))
> -               (:noinline t))
> -  "An xref item describes a reference to a location somewhere."
> -  summary location)
> -
> -(cl-defstruct (xref-match-item
> -               (:include xref-item)
> -               (:constructor xref-make-match (summary location length))
> -               (:noinline t))
> -  "A match xref item describes a search result."
> -  length)
> +(eval-and-compile
> +  (eval
> +   (let ((ni-supported (version< "27" emacs-version)))
> +     `(progn
> +        (cl-defstruct (xref-item
> +                       (:constructor xref-make (summary location))
> +                       ,@(if ni-supported
> +                             '((:noinline t))
> +                           nil))
> +          "An xref item describes a reference to a location somewhere."
> +          summary location)
> +
> +        (cl-defstruct (xref-match-item
> +                       (:include xref-item)
> +                       (:constructor xref-make-match (summary location
> length))
> +                       ,@(if ni-supported
> +                             '((:noinline t))
> +                           nil))
> +          "A match xref item describes a search result."
> +          length))))
> + t)
>
>  (cl-defgeneric xref-match-length ((item xref-match-item))
>    "Return the length of the match."

I suspect that you can get the same without `eval` with something like:

    (defmacro xref--defstruct (name &rest fields)
      (declare (indent 1))
      `(cl-defstruct ,(if (>= 27 emacs-major-version) name
                        (remq (assq :noinline name) name))
         ,@fields))

    (xref--defstruct (xref-item
                      (:noinline t)
                      (:constructor xref-make (summary location)))
      "An xref item describes a reference to a location somewhere."
      summary location)

    (xref--defstruct (xref-match-item
                      (:noinline t)
                      (:include xref-item)
                      (:constructor xref-make-match (summary location length)))
       "A match xref item describes a search result."
       length))))


-- Stefan