I sometimes find useful to return to the current reference after examining
its context. However, xref--next-error-function fails to jump to the
current reference. The following steps reproduce the problem.

emacs -Q lisp/progmodes/xref.el
M-? xref-make RET
n RET
M-<
C-u 0 M-g n

I know next-error + previous-error is a workaround, but the patch fixes the
bug.

Thanks,
Felicián