1) Create ~/test with a file with following contents:
multi
line

2) Visit directory using dired: C-f ~/test
3) Initiate regexp-replace by hitting Q
4) multi[[:space:]]line RET singeline RET
5) See that dired regexp replace failed reporting that no results were
found
6) Visit a file you have just created.
7) Initiate query-replace-regexp with C-M-%
8) Accept the suggested (previous) query-replace by hitting RET
9) See that the query is actually correct and finds the result.


In GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
 of 2018-05-29 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.12000000
Recent messages:
user-error: No matches for: multi[[:space:]]line
Mark set
Replaced 1 occurrence

Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --with-x-toolkit=gtk3 --with-xft --with-modules
 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong
 -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY
ACL GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS
GTK3 X11 MODULES THREADS LIBSYSTEMD LCMS2

Important settings:
  value of $LC_COLLATE: de_CH.UTF-8
  value of $LC_MONETARY: de_CH.UTF-8
  value of $LC_NUMERIC: de_CH.UTF-8
  value of $LC_TIME: lt_LT.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Dired by name

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq format-spec rfc822
mml mml-sec password-cache epa derived epg epg-config gnus-util rmail
rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils cl-extra help-mode easymenu find-dired
semantic/fw mode-local find-func xref cl-seq project eieio byte-opt
bytecomp byte-compile cconv eieio-core cl-macs gv eieio-loaddefs grep
compile comint ansi-color ring thingatpt dired-aux cl-loaddefs cl-lib
dired dired-loaddefs elec-pair leuven-theme time-date mule-util tooltip
eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote dbusbind inotify lcms2 dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 123229 14374)
 (symbols 48 22491 4)
 (miscs 40 103 176)
 (strings 32 34463 1497)
 (string-bytes 1 948663)
 (vectors 16 16681)
 (vector-slots 8 526030 13780)
 (floats 8 78 135)
 (intervals 56 300 0)
 (buffers 992 14))