bug#18163: 24.4.50; REGRESSION, font-lock in `emacs-lisp-mode': spurious `font-lock-warning-face'

[Drew Adams]

Recipe from emacs -Q: Type this into an Emacs-Lisp mode buffer:

(defun foo ()
  (condition-case nil
      (let ((toto (lambda (cand)
                     (foo)) bar)))
    (quit (tutu))))

The text "bar)))" is highlighted erroneously, with face
`font-lock-warning-face'.  It should not be highlighted at all.

If you add more right-parens, or any other text, at the end of the same
line as the warning-highlighted text, it too has that red face.  It
does not seem to matter what text you add.  You can remove all of the
warning-face text except the `b' (or any other char in place of `b'),
and it is still highlighted.  You can remove the SPC before the `b'
and it remains highlighted.  If you remove the whitespace before
"(foo..." on the same line, the highlighting remains.

If you remove the newline before the "(foo..." line then the
highlighting goes away.

The first build where I see this regression is this one:

In GNU Emacs 24.4.50.1 (i686-pc-mingw32)
 of 2014-04-25 on ODIEONE
Repository revision: 117024 
monnier@iro.umontreal.ca-20140425192226-frpjpmgs0r8ad9wc
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/snapshot/trunk
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -g3'
 LDFLAGS=-Lc:/Devel/emacs/lib 'CPPFLAGS=-DGC_MCHECK=1
 -Ic:/Devel/emacs/include''

The last build I have where there is not this regression is this one:

In GNU Emacs 24.4.50.1 (i686-pc-mingw32)
 of 2014-04-21 on ODIEONE
Repository revision: 117005 dancol@dancol.org-20140421180019-po4wdeg7gqvvlh5d
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/snapshot/trunk
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -g3'
 LDFLAGS=-Lc:/Devel/emacs/lib 'CPPFLAGS=-DGC_MCHECK=1
 -Ic:/Devel/emacs/include''

This is the build I'm sending this report from:

In GNU Emacs 24.4.50.1 (i686-pc-mingw32)
 of 2014-06-28 on ODIEONE
Bzr revision: 117431 rgm@gnu.org-20140628015517-eku6hj8mpgcvfnso
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/snapshot/trunk
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -g3'
 LDFLAGS=-Lc:/Devel/emacs/lib 'CPPFLAGS=-DGC_MCHECK=1
 -Ic:/Devel/emacs/include''