Should `frame-title-format' protect the match data?

[Philipp Stephani]

Hi,

consider

emacs -Q -eval "(setq frame-title-format '(\"\" (:eval (string-match \".\" \"a\"))))"

If you then run `query-replace' and actually try to replace something you get an error "args out of range" because the match data changed unexpectedly. This happens on master and the release branch, but not in Emacs 24.5.

Should `frame-title-format' protect the match data, or does Emacs expect users to do that?

Thanks,

Philipp