Explain, why `tramp-*-file-name-p' is a defsubst.

lisp/net/tramp-adb.el

@@ -111,6 +111,8 @@
     (start-file-process . tramp-adb-handle-start-file-process))
   "Alist of handler functions for Tramp ADB method.")
 
+;; It must be a `defsubst' in order to push the whole code into
+;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
 (defsubst tramp-adb-file-name-p (filename)
   "Check if it's a filename for ADB."

lisp/net/tramp-ftp.el

@@ -200,6 +200,8 @@ pass to the OPERATION."
 		 (inhibit-file-name-operation operation))
 	    (apply 'ange-ftp-hook-function operation args)))))))
 
+;; It must be a `defsubst' in order to push the whole code into
+;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
 (defsubst tramp-ftp-file-name-p (filename)
   "Check if it's a filename that should be forwarded to Ange-FTP."

lisp/net/tramp-gvfs.el

@@ -432,6 +432,8 @@ Every entry is a list (NAME ADDRESS).")
   "Alist of handler functions for Tramp GVFS method.
 Operations not mentioned here will be handled by the default Emacs primitives.")
 
+;; It must be a `defsubst' in order to push the whole code into
+;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
 (defsubst tramp-gvfs-file-name-p (filename)
   "Check if it's a filename handled by the GVFS daemon."

lisp/net/tramp-smb.el

@@ -265,6 +265,8 @@ This can be used to disable echo etc."
   :type 'string
   :version "24.3")
 
+;; It must be a `defsubst' in order to push the whole code into
+;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
 (defsubst tramp-smb-file-name-p (filename)
   "Check if it's a filename for SMB servers."