Tags: patch

The attached patch fixes an issue where the completion preview overlay
(of Completion Preview mode) could at certain cases appear in the wrong
place when point is in the middle of a symbol.

To observe the effect of this patch:

1. emacs -Q
2. In the *scratch* buffer, say M-x completion-preview-mode RET
3. Type "defaul-di"
4. C-3 C-b to place point before the hyphen
5. Type "t"
   The completion preview overlay appears after "-di", showing "rectory".
   So far so good.
6. M-x completion-preview-next-candidate RET
   Before this patch, the preview now shows "-directory", thus repeating
   the existing suffix "-di".  With this patch, the preview shows just
   "rectory", as expected.