Hello,

I reproduced this bug with Emacs 26.1 and 26.1.90 using -Q option.

When pressing 'g' (revert-buffer) in an *Occur* buffer, in the case of
having `list-matching-lines-jump-to-current-line' set to non-nil, the
function errors as it can't find orig-line.

I'm attaching a patch that adds a guard to the list of guards before
inserting the current line.

Cheers,

Raimon Grau