bug#19353: 25.0.50; Lazy Highlighting

[Dani Moncayo <dmoncayo@gmail.com>]

Recipe:
0. emacs -Q
1. Create and empty buffer.
2. Write there this text (without the hyphen lines):
--------------
fat cat path
too book cool
--------------
3. Place point just after the "a" in "path".
4. Type: C-s a t

Here, the "at" in "path" is not highlighted at all.  Wrong: it should
be lazy-highlighted because it's one match of the current search
string, that can be reached by repeating "C-s".  This bug becomes more
obvious if you type "C-s" several times at this moment.

5. Place point just after the first "o" in "cool".
6. Type: C-s o o

This second scenario is similar: the "oo" in "cool" should be
lazy-highlighted, because it's a match.  Well, in this case the second
"o" in "cool" cannot be (and is not) lazy-highlighted because it's the
current (partial) match, and the Isearch face must take precedence
over the lazy-highlighting.  But still, the first "o" in "cool" should
be lazy-highlighted.

Now type another "C-s", and you will see:
* The "oo" in "too" highlighted as the current match (correct).
* The "oo" in "book" lazy-highlighted (correct).
* The "oo" in "cool" not highlighted (wrong: should be
  lazy-highlighted).



In GNU Emacs 25.0.50.1 (i686-pc-mingw32)
 of 2014-11-30 on LEG570
Repository revision: 3517da701ea5d16c296745d6678988b06bee615d
Windowing system distributor `Microsoft Corp.', version 6.3.9600
Configured using:
 `configure --without-dbus --enable-checking=yes,glyphs
 CPPFLAGS=-DGLYPH_DEBUG=1'


-- 
Dani Moncayo