Fix error in completion for separate Tramp syntax

* lisp/net/tramp.el (tramp-completion-file-name-regexp-separate):
Tweak regexp.

* test/lisp/net/tramp-tests.el (tramp-test24-file-name-completion):
Run method and host name completion for all syntaxes.

2 files changed, 55 insertions, 26 deletions

diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 56a7b377124..33e5900f3c2 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -945,7 +945,7 @@ See `tramp-file-name-structure' for more explanations.
 On W32 systems, the volume letter must be ignored.")
 
 (defconst tramp-completion-file-name-regexp-separate
-  "\\`/\\[[^]]*\\'"
+  "\\`/\\(\\[[^]]*\\)?\\'"
   "Value for `tramp-completion-file-name-regexp' for separate remoting.
 See `tramp-file-name-structure' for more explanations.")
 
diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el
index 1d487bc12d7..8db54979b6d 100644
--- a/test/lisp/net/tramp-tests.el
+++ b/test/lisp/net/tramp-tests.el
@@ -2448,37 +2448,66 @@ This tests also `make-symbolic-link', `file-truename' and `add-name-to-file'."
   "Check `file-name-completion' and `file-name-all-completions'."
   (skip-unless (tramp--test-enabled))
 
+  ;; Method and host name in completion mode.  This kind of completion
+  ;; does not work on MS Windows.
+  (when (not (memq system-type '(cygwin windows-nt)))
+    (let ((method (file-remote-p tramp-test-temporary-file-directory 'method))
+          (host (file-remote-p tramp-test-temporary-file-directory 'host))
+          (orig-syntax tramp-syntax))
+
+      (unwind-protect
+          (dolist (syntax (tramp-syntax-values))
+            (tramp-change-syntax syntax)
+            (let ;; This is needed for the `simplified' syntax.
+                ((method-marker
+                  (if (zerop (length (tramp-method-regexp)))
+                      "" tramp-default-method-marker))
+                 ;; This is needed for the `separate' syntax.
+                 (prefix-format (substring (tramp-prefix-format) 1)))
+              ;; Complete method name.
+              (unless (or (zerop (length method))
+                          (zerop (length (tramp-method-regexp))))
+                (should
+                 (member
+                  (concat prefix-format method (tramp-postfix-method-format))
+                  (file-name-all-completions
+                   (concat prefix-format (substring method 0 1)) "/"))))
+              ;; Complete host name for default method.
+              (unless (zerop (length host))
+                (let ((tramp-default-method (or method tramp-default-method)))
+                  (should
+                   (member
+                    (concat
+                     prefix-format method-marker (tramp-postfix-method-format)
+                     host (tramp-postfix-host-format))
+                    (file-name-all-completions
+                     (concat
+                      prefix-format method-marker (tramp-postfix-method-format)
+                      (substring host 0 1))
+                     "/")))))
+              ;; Complete host name.
+              (unless (or (zerop (length method))
+                          (zerop (length (tramp-method-regexp)))
+                          (zerop (length host)))
+                (should
+                 (member
+                  (concat
+                   prefix-format method (tramp-postfix-method-format)
+                   host (tramp-postfix-host-format))
+                  (file-name-all-completions
+                   (concat prefix-format method (tramp-postfix-method-format))
+                   "/"))))))
+
+        ;; Cleanup.
+        (tramp-change-syntax orig-syntax))))
+
   (dolist (n-e '(nil t))
     (dolist (quoted (if tramp--test-expensive-test '(nil t) '(nil)))
       (let ((non-essential n-e)
-            (tmp-name (tramp--test-make-temp-name nil quoted))
-            (method (file-remote-p tramp-test-temporary-file-directory 'method))
-            (host (file-remote-p tramp-test-temporary-file-directory 'host)))
+            (tmp-name (tramp--test-make-temp-name nil quoted)))
 
         (unwind-protect
             (progn
-              ;; Method and host name in completion mode.  This kind
-              ;; of completion does not work on MS Windows.
-              (when (not (memq system-type '(cygwin windows-nt)))
-                (unless (zerop (length method))
-                  (should
-                   (member
-                    (format "%s:" method)
-                    (file-name-all-completions (substring method 0 1) "/"))))
-                (unless (zerop (length host))
-                  (let ((tramp-default-method (or method tramp-default-method)))
-                    (should
-                     (member
-                      (format "-:%s:" host)
-                      (file-name-all-completions
-                       (format "-:%s" (substring host 0 1)) "/")))))
-                (unless (or (zerop (length method)) (zerop (length host)))
-                  (should
-                   (member
-                    (format "%s:%s:" method host)
-                    (file-name-all-completions
-                     (format "%s:" method) "/")))))
-
               ;; Local files.
               (make-directory tmp-name)
               (should (file-directory-p tmp-name))