[Emacs-diffs] emacs-26 1c30f9f 05/39: Flymake diagnostics now apply to arbitrary buffer regions

[João Távora]

branch: emacs-26
commit 1c30f9fc08649649676ed812f1579f0948558ceb
Author: João Távora <address@hidden>
Commit: João Távora <address@hidden>

    Flymake diagnostics now apply to arbitrary buffer regions
    
    Make Flymake UI some 150 lines lighter
    
    Strip away much of the original implementation's complexity in
    manipulating objects representing diagnostics as well as creating and
    navigating overlays.
    
    Lay some groundwork for a more flexible approach that allows for
    different classes of diagnostics, not necessarily line-based.
    Importantly, one overlay per diagnostic is created, whereas the
    original implementation had one per line, and on it it concatenated
    the results of errors and warnings.
    
    This means that currently, an error and warning on the same line are
    problematic and the warning might be overlooked but this will soon be
    fixed by setting appropriate priorities.
    
    Since diagnostics can highlight arbitrary regions, not just lines, the
    faces were renamed.
    
    Tests pass and backward compatibility with interactive functions is
    maintained, but probably any third-party extension or customization
    relying on more than a trivial set of flymake.el internals has stopped
    working.
    
    * lisp/progmodes/flymake-proc.el
    (flymake-proc--diagnostics-for-pattern): Use new flymake-ler-make
    constructor syntax.
    
    * lisp/progmodes/flymake.el (flymake-ins-after)
    (flymake-set-at, flymake-er-make-er, flymake-er-get-line)
    (flymake-er-get-line-err-info-list, flymake-ler-set-file)
    (flymake-ler-set-full-file, flymake-ler-set-line)
    (flymake-get-line-err-count, flymake-get-err-count)
    (flymake-highlight-err-lines, flymake-overlay-p)
    (flymake-make-overlay, flymake-region-has-flymake-overlays)
    (flymake-find-err-info)
    (flymake-line-err-info-is-less-or-equal)
    (flymake-add-line-err-info, flymake-add-err-info)
    (flymake-get-first-err-line-no)
    (flymake-get-last-err-line-no, flymake-get-next-err-line-no)
    (flymake-get-prev-err-line-no, flymake-skip-whitespace)
    (flymake-goto-line, flymake-goto-next-error)
    (flymake-goto-prev-error, flymake-patch-err-text): Delete
    functions no longer used.
    (flymake-goto-next-error, flymake-goto-prev-error): Rewrite.
    (flymake-report): Rewrite.
    (flymake-popup-current-error-menu): Rewrite.
    (flymake--highlight-line): Rename from
    flymake-highlight-line.  Call `flymake--place-overlay.
    (flymake--place-overlay): New function.
    (flymake-ler-errorp): New predicate.
    (flymake-ler): Simplify.
    (flymake-error): Rename from
    flymake-errline.
    (flymake-warning): Rename from flymake-warnline.
    (flymake-warnline, flymake-errline): Obsoletion aliases.
    
    * test/lisp/progmodes/flymake-tests.el (warning-predicate-rx-gcc)
    (warning-predicate-function-gcc, warning-predicate-rx-perl)
    (warning-predicate-function-perl): Use face `flymake-warning'.
---
 lisp/progmodes/flymake-proc.el       |  54 ++--
 lisp/progmodes/flymake.el            | 472 ++++++++++++-----------------------
 test/lisp/progmodes/flymake-tests.el |   8 +-
 3 files changed, 189 insertions(+), 345 deletions(-)

diff --git a/lisp/progmodes/flymake-proc.el b/lisp/progmodes/flymake-proc.el
index bdfdf9a..0395fff 100644
--- a/lisp/progmodes/flymake-proc.el
+++ b/lisp/progmodes/flymake-proc.el
@@ -395,33 +395,41 @@ Create parent directories as needed."
 
 (defun flymake-proc--diagnostics-for-pattern (proc pattern)
   (condition-case err
-      (pcase-let ((`(,regexp ,file-idx ,line-idx ,_col-idx ,message-idx)
+      (pcase-let ((`(,regexp ,file-idx ,line-idx ,col-idx ,message-idx)
                    pattern)
                   (retval))
         (while (search-forward-regexp regexp nil t)
-          (let ((fname (and file-idx (match-string file-idx)))
-                (message (and message-idx (match-string message-idx)))
-                (line-number (and line-idx (string-to-number
-                                            (match-string line-idx)))))
+          (let* ((fname (and file-idx (match-string file-idx)))
+                 (message (and message-idx (match-string message-idx)))
+                 (line-string (and line-idx (match-string line-idx)))
+                 (line-number (and line-string
+                                   (string-to-number line-string)))
+                 (col-string (and col-idx (match-string col-idx)))
+                 (col-number (and col-string
+                                  (string-to-number col-string))))
             (with-current-buffer (process-buffer proc)
-              (push (flymake-ler-make-ler
-                     fname
-                     line-number
-                     (if (and message
-                              (cond ((stringp flymake-proc-warning-predicate)
-                                     (string-match 
flymake-proc-warning-predicate
-                                                   message))
-                                    ((functionp flymake-proc-warning-predicate)
-                                     (funcall flymake-proc-warning-predicate
-                                              message))))
-                         "w"
-                       "e")
-                     message
-                     (and fname
-                          (funcall (flymake-proc--get-real-file-name-function
-                                    fname)
-                                   fname)))
-                    retval))))
+              (push
+               (flymake-ler-make
+                :file fname
+                :line line-number
+                :col col-number
+                :type (if (and
+                           message
+                           (cond ((stringp flymake-proc-warning-predicate)
+                                  (string-match flymake-proc-warning-predicate
+                                                message))
+                                 ((functionp flymake-proc-warning-predicate)
+                                  (funcall flymake-proc-warning-predicate
+                                           message))))
+                          "w"
+                        "e")
+                :text message
+                :full-file (and fname
+                                (funcall
+                                 (flymake-proc--get-real-file-name-function
+                                  fname)
+                                 fname)))
+               retval))))
         retval)
     (error
      (flymake-log 1 "Error parsing process output for pattern %s: %s"
diff --git a/lisp/progmodes/flymake.el b/lisp/progmodes/flymake.el
index a360306..f00915a 100644
--- a/lisp/progmodes/flymake.el
+++ b/lisp/progmodes/flymake.el
@@ -136,223 +136,119 @@ are the string substitutions (see the function 
`format')."
       (let* ((msg (apply #'format-message text args)))
        (message "%s" msg))))
 
-(defun flymake-ins-after (list pos val)
-  "Insert VAL into LIST after position POS.
-POS counts from zero."
-  (let ((tmp (copy-sequence list)))
-    (setcdr (nthcdr pos tmp) (cons val (nthcdr (1+ pos) tmp)))
-    tmp))
-
-(defun flymake-set-at (list pos val)
-  "Set VAL at position POS in LIST.
-POS counts from zero."
-  (let ((tmp (copy-sequence list)))
-    (setcar (nthcdr pos tmp) val)
-    tmp))
-
-(defun flymake-er-make-er (line-no line-err-info-list)
-  (list line-no line-err-info-list))
-
-(defun flymake-er-get-line (err-info)
-  (nth 0 err-info))
-
-(defun flymake-er-get-line-err-info-list (err-info)
-  (nth 1 err-info))
-
 (cl-defstruct (flymake-ler
-               (:constructor nil)
-               (:constructor flymake-ler-make-ler (file line type text 
&optional full-file)))
-  file line type text full-file)
-
-(defun flymake-ler-set-file (line-err-info file)
-  (flymake-ler-make-ler file
-                       (flymake-ler-line line-err-info)
-                       (flymake-ler-type line-err-info)
-                       (flymake-ler-text line-err-info)
-                       (flymake-ler-full-file line-err-info)))
-
-(defun flymake-ler-set-full-file (line-err-info full-file)
-  (flymake-ler-make-ler (flymake-ler-file line-err-info)
-                       (flymake-ler-line line-err-info)
-                       (flymake-ler-type line-err-info)
-                       (flymake-ler-text line-err-info)
-                       full-file))
-
-(defun flymake-ler-set-line (line-err-info line)
-  (flymake-ler-make-ler (flymake-ler-file line-err-info)
-                       line
-                       (flymake-ler-type line-err-info)
-                       (flymake-ler-text line-err-info)
-                       (flymake-ler-full-file line-err-info)))
-
-(defun flymake-get-line-err-count (line-err-info-list type)
-  "Return number of errors of specified TYPE.
-Value of TYPE is either \"e\" or \"w\"."
-  (let* ((idx        0)
-        (count      (length line-err-info-list))
-        (err-count  0))
-
-    (while (< idx count)
-      (when (equal type (flymake-ler-type (nth idx line-err-info-list)))
-       (setq err-count (1+ err-count)))
-      (setq idx (1+ idx)))
-    err-count))
-
-(defun flymake-get-err-count (err-info-list type)
-  "Return number of errors of specified TYPE for ERR-INFO-LIST."
-  (let* ((idx        0)
-        (count      (length err-info-list))
-        (err-count  0))
-    (while (< idx count)
-      (setq err-count (+ err-count (flymake-get-line-err-count (nth 1 (nth idx 
err-info-list)) type)))
-      (setq idx (1+ idx)))
-    err-count))
-
-(defun flymake-highlight-err-lines (err-info-list)
-  "Highlight error lines in BUFFER using info from ERR-INFO-LIST."
-  (save-excursion
-    (dolist (err err-info-list)
-      (flymake-highlight-line (car err) (nth 1 err)))))
-
-(defun flymake-overlay-p (ov)
-  "Determine whether overlay OV was created by flymake."
-  (and (overlayp ov) (overlay-get ov 'flymake-overlay)))
-
-(defun flymake-make-overlay (beg end tooltip-text face bitmap)
-  "Allocate a flymake overlay in range BEG and END."
-  (when (not (flymake-region-has-flymake-overlays beg end))
-    (let ((ov (make-overlay beg end nil t))
-         (fringe (and flymake-fringe-indicator-position
-                      (propertize "!" 'display
-                                  (cons flymake-fringe-indicator-position
-                                        (if (listp bitmap)
-                                            bitmap
-                                          (list bitmap)))))))
-      (overlay-put ov 'face           face)
-      (overlay-put ov 'help-echo      tooltip-text)
+               (:constructor flymake-ler-make))
+  file line col type text full-file)
+
+(defun flymake-ler-errorp (diag)
+  "Tell if DIAG is a flymake error or something else"
+  (string= "e" (flymake-ler-type diag)))
+
+(defun flymake--place-overlay (beg end tooltip-text face bitmap diag)
+  "Place a flymake overlay in range BEG and END.
+Make a flymake fringe overlay for the line at BEG, if needed."
+  (let* ((fringe-overlay
+          (or (cl-find-if (lambda (ov)
+                            (overlay-get ov 'flymake--fringe-overlay))
+                          (overlays-at beg))
+              (make-overlay beg (1+ beg)))))
+    (let ((ov fringe-overlay))
+      (overlay-put ov 'help-echo
+                   (concat tooltip-text "\n"
+                           (overlay-get ov 'help-echo)))
+      (overlay-put ov 'before-string
+                   (and flymake-fringe-indicator-position
+                        (propertize "!" 'display
+                                    (cons flymake-fringe-indicator-position
+                                          (if (listp bitmap)
+                                              bitmap
+                                            (list bitmap))
+                                          ))))
+      (overlay-put ov 'evaporate t)
       (overlay-put ov 'flymake-overlay  t)
       (overlay-put ov 'priority 100)
-      (overlay-put ov 'evaporate t)
-      (overlay-put ov 'before-string fringe)
-      ;;+(flymake-log 3 "created overlay %s" ov)
       ov)
-    (flymake-log 3 "created an overlay at (%d-%d)" beg end)))
+    (let ((ov (make-overlay beg end)))
+      (overlay-put ov 'face face)
+      (overlay-put ov 'help-echo
+                   (concat tooltip-text "\n"
+                           (overlay-get ov 'help-echo)))
+      (overlay-put ov 'evaporate t)
+      (overlay-put ov 'flymake-overlay t)
+      (overlay-put ov 'flymake--diagnostic diag))
+    (cl-loop for i from 0
+             for overlay in
+             (flymake--overlays
+              'flymake--diagnostic
+              (lambda (_ov1 ov2)
+                (flymake-ler-errorp
+                 (overlay-get ov2 'flymake--diagnostic)))
+              beg end)
+             do (overlay-put overlay 'priority (+ 100 i)))))
+
+(defun flymake--overlays (&optional filter compare beg end)
+  (cl-remove-if-not
+   (lambda (ov)
+     (and (overlay-get ov 'flymake-overlay)
+          (or (not filter)
+              (cond ((functionp filter) (funcall filter ov))
+                    ((symbolp filter) (overlay-get ov filter))))))
+   (save-restriction
+     (widen)
+     (let ((ovs (overlays-in (or beg (point-min))
+                             (or end (point-max)))))
+       (if compare
+           (cl-sort ovs
+                    compare
+                    :key #'overlay-start)
+         ovs)))))
 
 (defun flymake-delete-own-overlays ()
   "Delete all flymake overlays in BUFFER."
-  (dolist (ol (overlays-in (point-min) (point-max)))
-    (when (flymake-overlay-p ol)
-      (delete-overlay ol)
-      ;;+(flymake-log 3 "deleted overlay %s" ol)
-      )))
-
-(defun flymake-region-has-flymake-overlays (beg end)
-  "Check if region specified by BEG and END has overlay.
-Return t if it has at least one flymake overlay, nil if no overlay."
-  (let ((ov                  (overlays-in beg end))
-       (has-flymake-overlays  nil))
-    (while (consp ov)
-      (when (flymake-overlay-p (car ov))
-       (setq has-flymake-overlays t))
-      (setq ov (cdr ov)))
-    has-flymake-overlays))
-
-(defface flymake-errline
+  (mapc #'delete-overlay (flymake--overlays)))
+
+(defface flymake-error
   '((((supports :underline (:style wave)))
      :underline (:style wave :color "Red1"))
     (t
      :inherit error))
-  "Face used for marking error lines."
+  "Face used for marking error regions."
   :version "24.4"
   :group 'flymake)
 
-(defface flymake-warnline
+(defface flymake-warning
   '((((supports :underline (:style wave)))
      :underline (:style wave :color "DarkOrange"))
     (t
      :inherit warning))
-  "Face used for marking warning lines."
+  "Face used for marking warning regions."
   :version "24.4"
   :group 'flymake)
 
-(defun flymake-highlight-line (line-no line-err-info-list)
-  "Highlight line LINE-NO in current buffer.
-Perhaps use text from LINE-ERR-INFO-LIST to enhance highlighting."
-  (goto-char (point-min))
-  (forward-line (1- line-no))
-  (pcase-let* ((beg (progn (back-to-indentation) (point)))
-               (end (progn
-                      (end-of-line)
-                      (skip-chars-backward " \t\f\t\n" beg)
-                      (if (eq (point) beg)
-                          (line-beginning-position 2)
-                        (point))))
-               (tooltip-text (mapconcat #'flymake-ler-text line-err-info-list 
"\n"))
-               (`(,face ,bitmap)
-                (if (> (flymake-get-line-err-count line-err-info-list "e") 0)
-                    (list 'flymake-errline flymake-error-bitmap)
-                  (list 'flymake-warnline flymake-warning-bitmap))))
-    (flymake-make-overlay beg end tooltip-text face bitmap)))
-
-(defun flymake-find-err-info (err-info-list line-no)
-  "Find (line-err-info-list pos) for specified LINE-NO."
-  (if err-info-list
-      (let* ((line-err-info-list  nil)
-            (pos       0)
-            (count     (length err-info-list)))
-
-       (while (and (< pos count) (< (car (nth pos err-info-list)) line-no))
-         (setq pos (1+ pos)))
-       (when (and (< pos count) (equal (car (nth pos err-info-list)) line-no))
-         (setq line-err-info-list (flymake-er-get-line-err-info-list (nth pos 
err-info-list))))
-       (list line-err-info-list pos))
-    '(nil 0)))
-
-(defun flymake-line-err-info-is-less-or-equal (line-one line-two)
-  (or (string< (flymake-ler-type line-one) (flymake-ler-type line-two))
-      (and (string= (flymake-ler-type line-one) (flymake-ler-type line-two))
-          (not (flymake-ler-file line-one)) (flymake-ler-file line-two))
-      (and (string= (flymake-ler-type line-one) (flymake-ler-type line-two))
-          (or (and      (flymake-ler-file line-one)       (flymake-ler-file 
line-two))
-              (and (not (flymake-ler-file line-one)) (not (flymake-ler-file 
line-two)))))))
-
-(defun flymake-add-line-err-info (line-err-info-list line-err-info)
-  "Update LINE-ERR-INFO-LIST with the error LINE-ERR-INFO.
-For the format of LINE-ERR-INFO, see `flymake-ler-make-ler'.
-The new element is inserted in the proper position, according to
-the predicate `flymake-line-err-info-is-less-or-equal'.
-The updated value of LINE-ERR-INFO-LIST is returned."
-  (if (not line-err-info-list)
-      (list line-err-info)
-    (let* ((count  (length line-err-info-list))
-          (idx    0))
-      (while (and (< idx count) (flymake-line-err-info-is-less-or-equal (nth 
idx line-err-info-list) line-err-info))
-       (setq idx (1+ idx)))
-      (cond ((equal 0     idx)    (setq line-err-info-list (cons line-err-info 
line-err-info-list)))
-           (t                    (setq line-err-info-list (flymake-ins-after 
line-err-info-list (1- idx) line-err-info))))
-      line-err-info-list)))
-
-(defun flymake-add-err-info (err-info-list line-err-info)
-  "Update ERR-INFO-LIST with the error LINE-ERR-INFO, preserving sort order.
-Returns the updated value of ERR-INFO-LIST.
-For the format of ERR-INFO-LIST, see `flymake-err-info'.
-For the format of LINE-ERR-INFO, see `flymake-ler-make-ler'."
-  (let* ((line-no             (if (flymake-ler-file line-err-info) 1 
(flymake-ler-line line-err-info)))
-        (info-and-pos        (flymake-find-err-info err-info-list line-no))
-        (exists              (car info-and-pos))
-        (pos                 (nth 1 info-and-pos))
-        (line-err-info-list  nil)
-        (err-info            nil))
-
-    (if exists
-       (setq line-err-info-list (flymake-er-get-line-err-info-list (car 
(nthcdr pos err-info-list)))))
-    (setq line-err-info-list (flymake-add-line-err-info line-err-info-list 
line-err-info))
-
-    (setq err-info (flymake-er-make-er line-no line-err-info-list))
-    (cond (exists             (setq err-info-list (flymake-set-at 
err-info-list pos err-info)))
-         ((equal 0 pos)      (setq err-info-list (cons err-info 
err-info-list)))
-         (t                  (setq err-info-list (flymake-ins-after 
err-info-list (1- pos) err-info))))
-    err-info-list))
+(define-obsolete-face-alias 'flymake-warnline 'flymake-warning "26.1")
+(define-obsolete-face-alias 'flymake-errline 'flymake-error "26.1")
+
+(defun flymake--highlight-line (diagnostic)
+  "Highlight buffer with info in DIAGNOSTIC.
+Reuse overlays if necessary
+Perhaps use the message text as a hint to enhance highlighting."
+  (save-excursion
+    (goto-char (point-min))
+    (let ((line-no (flymake-ler-line diagnostic)))
+      (forward-line (1- line-no))
+      (pcase-let* ((beg (progn (back-to-indentation) (point)))
+                   (end (progn
+                          (end-of-line)
+                          (skip-chars-backward " \t\f\t\n" beg)
+                          (if (eq (point) beg)
+                              (line-beginning-position 2)
+                            (point))))
+                   (tooltip-text (flymake-ler-text diagnostic))
+                   (`(,face ,bitmap)
+                    (if (equal "e" (flymake-ler-type diagnostic))
+                        (list 'flymake-errline flymake-error-bitmap)
+                      (list 'flymake-warnline flymake-warning-bitmap))))
+        (flymake--place-overlay beg end tooltip-text face bitmap 
diagnostic)))))
 
 (defvar-local flymake-is-running nil
   "If t, flymake syntax check process is running for the current buffer.")
@@ -368,7 +264,7 @@ For the format of LINE-ERR-INFO, see 
`flymake-ler-make-ler'."
 
        (setq flymake-last-change-time nil)
        (flymake-log 3 "starting syntax check as more than 1 second passed 
since last change")
-       (flymake-start-syntax-check)))))
+       (flymake--start-syntax-check)))))
 
 (define-obsolete-function-alias 'flymake-display-err-menu-for-current-line
   'flymake-popup-current-error-menu "24.4")
@@ -376,38 +272,36 @@ For the format of LINE-ERR-INFO, see 
`flymake-ler-make-ler'."
 (defun flymake-popup-current-error-menu (&optional event)
   "Pop up a menu with errors/warnings for current line."
   (interactive (list last-nonmenu-event))
-  (let* ((line-no (line-number-at-pos))
-         (errors (or (car (flymake-find-err-info flymake-err-info line-no))
-                     (user-error "No errors for current line")))
-         (menu (mapcar (lambda (x)
-                         (if (flymake-ler-file x)
-                             (cons (format "%s - %s(%d)"
-                                           (flymake-ler-text x)
-                                           (flymake-ler-file x)
-                                           (flymake-ler-line x))
-                                   x)
-                           (list (flymake-ler-text x))))
-                       errors))
+  (let* ((diag-overlays (or
+                         (flymake--overlays 'flymake--diagnostic nil
+                                            (line-beginning-position)
+                                            (line-end-position))
+                         (user-error "No flymake problem for current line")))
+         (menu (mapcar (lambda (ov)
+                         (let ((diag (overlay-get ov 'flymake--diagnostic)))
+                           (cons (format "%s - %s(%s)"
+                                         (flymake-ler-text diag)
+                                         (or (flymake-ler-file diag)
+                                             "(no file)")
+                                         (or (flymake-ler-line diag)
+                                             "?"))
+                                 ov)))
+                       diag-overlays))
          (event (if (mouse-event-p event)
                     event
                   (list 'mouse-1 (posn-at-point))))
-         (title (format "Line %d: %d error(s), %d warning(s)"
-                        line-no
-                        (flymake-get-line-err-count errors "e")
-                        (flymake-get-line-err-count errors "w")))
+         (diagnostics (mapcar (lambda (ov) (overlay-get ov 
'flymake--diagnostic))
+                              diag-overlays))
+         (title (format "Line %d: %d error(s), %d other(s)"
+                        (line-number-at-pos)
+                        (cl-count-if #'flymake-ler-errorp diagnostics)
+                        (cl-count-if-not #'flymake-ler-errorp diagnostics)))
          (choice (x-popup-menu event (list title (cons "" menu)))))
     (flymake-log 3 "choice=%s" choice)
-    (when choice
-      (flymake-goto-file-and-line (flymake-ler-full-file choice)
-                                  (flymake-ler-line choice)))))
-
-(defun flymake-goto-file-and-line (file line)
-  "Try to get buffer for FILE and goto line LINE in it."
-  (if (not (file-exists-p file))
-      (flymake-log 1 "File %s does not exist" file)
-    (find-file file)
-    (goto-char (point-min))
-    (forward-line (1- line))))
+    ;; FIXME: What is the point of going to the problem locus if we're
+    ;; certainly already there?
+    ;;
+    (when choice (goto-char (overlay-start choice)))))
 
 ;; flymake minor mode declarations
 (defvar-local flymake-mode-line nil)
@@ -452,33 +346,19 @@ For the format of LINE-ERR-INFO, see 
`flymake-ler-make-ler'."
 (defun flymake-report (diagnostics)
   (save-restriction
     (widen)
-    (mapc #'flymake--fix-line-numbers diagnostics)
     (flymake-delete-own-overlays)
-    (setq flymake-err-info
-          (cl-loop with grouped
-                   for diag in diagnostics
-                   for line = (flymake-ler-line diag)
-                   for existing = (assoc line grouped)
-                   if existing
-                   do (setcdr existing
-                              (list diag (cl-second existing)))
-                   else
-                   do (push (list line (list diag)) grouped)
-                   finally (return grouped)))
-    (flymake-highlight-err-lines flymake-err-info)
-    (let ((err-count (flymake-get-err-count flymake-err-info "e"))
-          (warn-count (flymake-get-err-count flymake-err-info "w")))
+    (mapc #'flymake--fix-line-numbers diagnostics)
+    (mapc #'flymake--highlight-line diagnostics)
+    (let ((err-count (cl-count-if #'flymake-ler-errorp diagnostics))
+          (warn-count (cl-count-if-not #'flymake-ler-errorp diagnostics)))
       (when flymake-check-start-time
-        (flymake-log 2 "%s: %d error(s), %d warning(s) in %.2f second(s)"
+        (flymake-log 2 "%s: %d error(s), %d other(s) in %.2f second(s)"
                      (buffer-name) err-count warn-count
                      (- (float-time) flymake-check-start-time)))
-      (if (and (equal 0 err-count) (equal 0 warn-count))
+      (if (null diagnostics)
           (flymake-report-status "" "")
         (flymake-report-status (format "%d/%d" err-count warn-count) "")))))
 
-(defvar-local flymake--backend nil
-  "The currently active backend selected by `flymake-mode'")
-
 ;;;###autoload
 (define-minor-mode flymake-mode nil
   :group 'flymake :lighter flymake-mode-line
@@ -507,7 +387,7 @@ For the format of LINE-ERR-INFO, see 
`flymake-ler-make-ler'."
                  ;; trying if the directory is read-only (bug#8954).
                  (file-writable-p (file-name-directory buffer-file-name)))
         (with-demoted-errors
-            (flymake-start-syntax-check))))))
+            (flymake--start-syntax-check))))))
 
    ;; Turning the mode OFF.
    (t
@@ -542,14 +422,14 @@ For the format of LINE-ERR-INFO, see 
`flymake-ler-make-ler'."
   (let((new-text (buffer-substring start stop)))
     (when (and flymake-start-syntax-check-on-newline (equal new-text "\n"))
       (flymake-log 3 "starting syntax check as new-line has been seen")
-      (flymake-start-syntax-check))
+      (flymake--start-syntax-check))
     (setq flymake-last-change-time (float-time))))
 
 (defun flymake-after-save-hook ()
   (if (local-variable-p 'flymake-mode (current-buffer))        ; (???) other 
way to determine whether flymake is active in buffer being saved?
       (progn
        (flymake-log 3 "starting syntax check as buffer was saved")
-       (flymake-start-syntax-check)))) ; no more mode 3. cannot start check if 
mode 3 (to temp copies) is active - (???)
+       (flymake--start-syntax-check)))) ; no more mode 3. cannot start check 
if mode 3 (to temp copies) is active - (???)
 
 (defun flymake-kill-buffer-hook ()
   (when flymake-timer
@@ -558,85 +438,41 @@ For the format of LINE-ERR-INFO, see 
`flymake-ler-make-ler'."
 
 ;;;###autoload
 (defun flymake-find-file-hook ()
-  ;;+(when flymake-start-syntax-check-on-find-file
-  ;;+    (flymake-log 3 "starting syntax check on file open")
-  ;;+    (flymake-start-syntax-check)
-  ;;+)
   (when (and (not (local-variable-p 'flymake-mode (current-buffer)))
             (flymake-can-syntax-check-file buffer-file-name))
     (flymake-mode)
     (flymake-log 3 "automatically turned ON flymake mode")))
 
-(defun flymake-get-first-err-line-no (err-info-list)
-  "Return first line with error."
-  (when err-info-list
-    (flymake-er-get-line (car err-info-list))))
-
-(defun flymake-get-last-err-line-no (err-info-list)
-  "Return last line with error."
-  (when err-info-list
-    (flymake-er-get-line (nth (1- (length err-info-list)) err-info-list))))
-
-(defun flymake-get-next-err-line-no (err-info-list line-no)
-  "Return next line with error."
-  (when err-info-list
-    (let* ((count  (length err-info-list))
-          (idx    0))
-      (while (and (< idx count) (>= line-no (flymake-er-get-line (nth idx 
err-info-list))))
-       (setq idx (1+ idx)))
-      (if (< idx count)
-         (flymake-er-get-line (nth idx err-info-list))))))
-
-(defun flymake-get-prev-err-line-no (err-info-list line-no)
-  "Return previous line with error."
-  (when err-info-list
-    (let* ((count (length err-info-list)))
-      (while (and (> count 0) (<= line-no (flymake-er-get-line (nth (1- count) 
err-info-list))))
-       (setq count (1- count)))
-      (if (> count 0)
-         (flymake-er-get-line (nth (1- count) err-info-list))))))
-
-(defun flymake-skip-whitespace ()
-  "Move forward until non-whitespace is reached."
-  (while (looking-at "[ \t]")
-    (forward-char)))
-
-(defun flymake-goto-line (line-no)
-  "Go to line LINE-NO, then skip whitespace."
-  (goto-char (point-min))
-  (forward-line (1- line-no))
-  (flymake-skip-whitespace))
-
-(defun flymake-goto-next-error ()
-  "Go to next error in err ring."
-  (interactive)
-  (let ((line-no (flymake-get-next-err-line-no flymake-err-info 
(line-number-at-pos))))
-    (when (not line-no)
-      (setq line-no (flymake-get-first-err-line-no flymake-err-info))
-      (flymake-log 1 "passed end of file"))
-    (if line-no
-       (flymake-goto-line line-no)
-      (flymake-log 1 "no errors in current buffer"))))
-
-(defun flymake-goto-prev-error ()
-  "Go to previous error in err ring."
-  (interactive)
-  (let ((line-no (flymake-get-prev-err-line-no flymake-err-info 
(line-number-at-pos))))
-    (when (not line-no)
-      (setq line-no (flymake-get-last-err-line-no flymake-err-info))
-      (flymake-log 1 "passed beginning of file"))
-    (if line-no
-       (flymake-goto-line line-no)
-      (flymake-log 1 "no errors in current buffer"))))
-
-(defun flymake-patch-err-text (string)
-  (if (string-match "^[\n\t :0-9]*\\(.*\\)$" string)
-      (match-string 1 string)
-    string))
+(defun flymake-goto-next-error (&optional n interactive)
+  "Go to next, or Nth next, flymake error in buffer."
+  (interactive (list 1 t))
+  (let* ((n (or n 1))
+        (ovs (flymake--overlays 'flymake--diagnostic
+                                (if (cl-plusp n) #'< #'>)))
+        (chain (cl-member-if (lambda (ov)
+                               (if (cl-plusp n)
+                                   (> (overlay-start ov)
+                                       (point))
+                                 (< (overlay-start ov)
+                                     (point))))
+                             ovs))
+        (target (nth (1- n) chain)))
+    (if target
+       (goto-char (overlay-start target))
+      (when interactive
+       (user-error "No more flymake errors")))))
+
+(defun flymake-goto-prev-error (&optional n interactive)
+  "Go to previous, or Nth previous, flymake error in buffer."
+  (interactive (list 1 t))
+  (flymake-goto-next-error (- (or n 1)) interactive))
 
 (provide 'flymake)
 
-(declare-function flymake-start-syntax-check "flymake-proc")
+(defun flymake--start-syntax-check ()
+  (flymake-proc-start-syntax-check))
+
+(declare-function flymake-proc-start-syntax-check "flymake-proc")
 (declare-function flymake-can-syntax-check-file "flymake-proc")
 
 (require 'flymake-proc)
diff --git a/test/lisp/progmodes/flymake-tests.el 
b/test/lisp/progmodes/flymake-tests.el
index dda72a3..a018f11 100644
--- a/test/lisp/progmodes/flymake-tests.el
+++ b/test/lisp/progmodes/flymake-tests.el
@@ -51,26 +51,26 @@
 (ert-deftest warning-predicate-rx-gcc ()
   "Test GCC warning via regexp predicate."
   (skip-unless (and (executable-find "gcc") (executable-find "make")))
-  (should (eq 'flymake-warnline
+  (should (eq 'flymake-warning
               (flymake-tests--current-face "test.c" "^[Ww]arning"))))
 
 (ert-deftest warning-predicate-function-gcc ()
   "Test GCC warning via function predicate."
   (skip-unless (and (executable-find "gcc") (executable-find "make")))
-  (should (eq 'flymake-warnline
+  (should (eq 'flymake-warning
               (flymake-tests--current-face "test.c"
                (lambda (msg) (string-match "^[Ww]arning" msg))))))
 
 (ert-deftest warning-predicate-rx-perl ()
   "Test perl warning via regular expression predicate."
   (skip-unless (executable-find "perl"))
-  (should (eq 'flymake-warnline
+  (should (eq 'flymake-warning
               (flymake-tests--current-face "test.pl" "^Scalar value"))))
 
 (ert-deftest warning-predicate-function-perl ()
   "Test perl warning via function predicate."
   (skip-unless (executable-find "perl"))
-  (should (eq 'flymake-warnline
+  (should (eq 'flymake-warning
               (flymake-tests--current-face
                "test.pl"
                (lambda (msg) (string-match "^Scalar value" msg))))))