Re: `M-.' can't skip to the corresponding DEFUN from within the Apropos buffer.

[Daniel Martín]

Hongyi Zhao <hongyi.zhao@gmail.com> writes:

> Say, I've the following content snippet in the Apropos buffer:
>
> !cons
>   Macro: Destructive: Set CDR to the cons of CAR and CDR.
>   Properties: edebug-form-spec
>
> If I put the cursor on cons, NOT !cons, and then hit `M-.', Emacs
> can't skip to the DEFUN of cons. But if I do the same operations in
> scratch buffer, it will do the trick.
>
> Any hints for this behavior shown by Emacs? And how to obtain the same
> effect in other buffers as shown in scratch buffer?
>
> Regards

It depends on the variable xref-backend-functions (which can be made
buffer-local).  In general (and in Apropos buffers in particular), that
special hook only queries the Etags backend (etags--xref-backend), but
in the scratch buffer and other elisp-mode buffers it also queries the
Elisp backend (elisp--xref-backend), which uses the Emacs load history
to go to the definition.

So to have what you want, you could either:

- Generate TAGS for Emacs sources ("make tags" from a checked out Emacs
  source code directory).  Then M-x visit-tags-table RET
  <Emacs_source_dir>/src/TAGS RET.  That would also work for apropos
  functions and commands that are implemented in C.

- Create a buffer-local binding for xref-backend-functions in Apropos
  buffers where you prepend elisp--xref-backend to the list.