Make the comment test more robust by not relying on font-lock

beginend.el

@@ -250,12 +250,21 @@ BEGIN-BODY and END-BODY are two `progn' expressions passed to respectively
     (magit-section-backward)
     (magit-section-backward)))
 
-;; Copy/pasted from expand-region
-(defun beginend--point-is-in-comment-p ()
-  "Return non-nil if point is in comment."
-  (or (nth 4 (syntax-ppss))
-      (memq (get-text-property (point) 'face)
-            '(font-lock-comment-face font-lock-comment-delimiter-face))))
+(defun beginend--point-is-in-comment-p (&optional p)
+  "Return non-nil if point is in comment.
+
+If optional argument P is present test at that point instead of `point'."
+  (setq p (or p (point)))
+  (ignore-errors
+    (save-excursion
+      (or (nth 4 (syntax-ppss p))
+          (eq (char-syntax (char-after p)) ?<)
+          (let ((s (car (syntax-after p))))
+            (when s
+              (or (and (/= 0 (logand (lsh 1 16) s))
+                       (nth 4 (syntax-ppss (+ p 2))))
+                  (and (/= 0 (logand (lsh 1 17) s))
+                       (nth 4 (syntax-ppss (+ p 1)))))))))))
 
 (defun beginend--prog-mode-code-position-p ()
   "Return non-nil if point, at beginning of line, is inside code."