bug#19829: 25.0.50; query-replace in rectangle regions do not honor boundaries

[Stefan Monnier]

> Rewriting the complex function `perform-replace' to work on several
> region chunks is not needed because the most suitable way is to use
> `isearch-filter-predicate' for this specific case of search/replace.

I don't see how that's relevant: you still should not check
rectangle-mark-mode.

If you want to avoid the isearch-filter-predicate in the "normal" case,
that's OK, but you should do it by checking the value returned by
region-extract-function.


        Stefan