On Sat, 6 May 2017, zhanghj wrote:

> The doc says:
> In TO-STRING, ‘\&’ or ‘\0’ stands for whatever matched the whole of
> REGEXP, and ‘\N’ (where N is a digit) stands for whatever matched
> the Nth ‘\(...\)’ (1-based) in REGEXP.  The ‘\(...\)’ groups are
> counted from 1.
>
> But when using \0, emacs gives the following error message:
> match-substitute-replacement: Invalid use of ‘\’ in replacement text
>
> Using \& is OK.
Thanks.
The docstring for `query-replace-regexp' was updated in commit 38f4b8ea615
to fix Bug#23884.
Apparently, \0 has never referred to the whole match in this command
(\& it does), so we might want to skip \0 from this docstring and the 
manual.

Regards,
Tino