(error-data): Delete functionscratch/error-API

Remove `error-data` from the new error API: it is not really
compatible with a more abstract view of error descriptors, and
in practice it seems to be used only in two ways (both of them rare):

- To add some contextual info to an error.  We should maybe add
  a dedicated support for that, but it's not clear what shape it
  should take, ideally (there was a discussion about with Alan
  and myself in emacs-devel a few years ago).
- To do some other massaging whose correctness is dubious anyway.

* doc/lispref/control.texi (Handling Errors): Remove `error-data`.

* lisp/epa-file.el (epa-file--find-file-not-found-function): Don't use
`error-data`.
(epa-file--error-add-context): New function, extracted from
`epa-file-insert-file-contents`.
(epa-file-insert-file-contents): Use it instead of `error-data`.

* lisp/subr.el (error-data): Delete function.

1 files changed, 0 insertions, 4 deletions

diff --git a/lisp/subr.el b/lisp/subr.el
index 3cf4e8276d6..0c2acfec335 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -586,10 +586,6 @@ Defaults to `error'."
  "Return the symbol which represents the type of ERROR.
 \n(fn ERROR)")
 
-(defalias 'error-data #'cdr
-  "Return the slots attached to ERROR, as a list.
-\n(fn ERROR)")
-
 (defun error-has-type-p (error condition)
   "Return non-nil if ERROR is of type CONDITION (or a subtype of it)."
   (unless (error--p error)