of protection overlay. Changes that keep the same length of text are
probably harmless (e.g. just change of text properties). It's possible
that some harmful changes don't change text length, but the protection
overlays are already unable to catch all important changes since they
only cover 1 character each at the edges.
cc-mode modifies text properties in the buffer to cache parsing results,
therefore it's important that yasnippet not kill yasnippets when parsing
is triggered by a function that only wants to parse the
buffer (e.g. which-function-mode).
* yasnippet.el (yas--on-protection-overlay-modification): Check length
of text change to decide if change is harmful. Fix docstring.