From 00d2a6bb2663106a6584ea229958d5bba32703d2 Mon Sep 17 00:00:00 2001
From: Daniel Colascione <dancol@dancol.org>
Date: Tue, 21 Jan 2014 15:42:59 -0800
Subject: [PATCH] Fix here-doc highlighting

---
 lisp/ChangeLog              |  9 +++++++++
 lisp/progmodes/sh-script.el | 16 ++++++++++------
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 94966f657c1..6bdf4463a6f 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,12 @@
+2014-01-21  Daniel Colascione  <dancol@dancol.org>
+
+	* progmodes/sh-script.el (sh--inside-noncommand-expression):
+	Correctly detect when we're inside an arithmetic expansion form
+	containing nested parenthesis.
+	(sh--maybe-here-document): Use `sh--inside-noncommand-expression`
+	to detect cases where we shouldn't expand "<<" to a heredoc
+	skeleton.
+
 2014-01-21  Stefan Monnier  <monnier@iro.umontreal.ca>
 
 	* emacs-lisp/eldoc.el: Properly remove message in minibuffer case.
diff --git a/lisp/progmodes/sh-script.el b/lisp/progmodes/sh-script.el
index daf8d299663..f41378f2f53 100644
--- a/lisp/progmodes/sh-script.el
+++ b/lisp/progmodes/sh-script.el
@@ -975,11 +975,14 @@ See `sh-feature'.")
     (let ((ppss (syntax-ppss pos)))
       (when (nth 1 ppss)
         (goto-char (nth 1 ppss))
-        (pcase (char-after)
-          ;; $((...)) or $[...] or ${...}.
-          (`?\( (and (eq ?\( (char-before))
-                     (eq ?\$ (char-before (1- (point))))))
-          ((or `?\{ `?\[) (eq ?\$ (char-before))))))))
+        (or
+         (pcase (char-after)
+           ;; ((...)) or $((...)) or $[...] or ${...}. Nested
+           ;; parenthesis can occur inside the first of these forms, so
+           ;; parse backward recursively.
+           (`?\( (eq ?\( (char-before)))
+           ((or `?\{ `?\[) (eq ?\$ (char-before))))
+         (sh--inside-noncommand-expression (1- (point))))))))
 
 (defun sh-font-lock-open-heredoc (start string eol)
   "Determine the syntax of the \\n after a <<EOF.
@@ -4265,7 +4268,8 @@ The document is bounded by `sh-here-document-word'."
   (or (not (looking-back "[^<]<<"))
       (save-excursion
 	(backward-char 2)
-	(sh-quoted-p))
+        (or (sh-quoted-p)
+            (sh--inside-noncommand-expression (point))))
       (nth 8 (syntax-ppss))
       (let ((tabs (if (string-match "\\`-" sh-here-document-word)
                       (make-string (/ (current-indentation) tab-width) ?\t)
-- 
2.39.2