Fix Flymake's user-visible accessors of diagnostic positions

Diagnostics are supported by overlays, and they can legitimately move
around.  So flymake-diagnostic-beg and flymake-diagnostic-end must
look up the overlay positions, not the immutable slots of the
flymake--diag structure, which become stale.

* lisp/progmodes/flymake.el (version): Bump to 1.0.8.
(flymake-diagnostic-beg, flymake-diagnostic-end): Use diag's
overlay.
(flymake-show-diagnostic): Use flymake-diagnostic-end,
flymake-diagnostic-beg.

1 files changed, 11 insertions, 5 deletions

diff --git a/lisp/progmodes/flymake.el b/lisp/progmodes/flymake.el
index d662aaf4257..e8a4334fe96 100644
--- a/lisp/progmodes/flymake.el
+++ b/lisp/progmodes/flymake.el
@@ -4,7 +4,7 @@
 
 ;; Author: Pavel Kobyakov <pk_at_work@yahoo.com>
 ;; Maintainer: João Távora <joaotavora@gmail.com>
-;; Version: 1.0.7
+;; Version: 1.0.8
 ;; Package-Requires: ((emacs "26.1"))
 ;; Keywords: c languages tools
 
@@ -344,11 +344,17 @@ diagnostics at BEG."
 (flymake--diag-accessor flymake-diagnostic-buffer flymake--diag-buffer buffer)
 (flymake--diag-accessor flymake-diagnostic-text flymake--diag-text text)
 (flymake--diag-accessor flymake-diagnostic-type flymake--diag-type type)
-(flymake--diag-accessor flymake-diagnostic-beg flymake--diag-beg beg)
-(flymake--diag-accessor flymake-diagnostic-end flymake--diag-end end)
 (flymake--diag-accessor flymake-diagnostic-backend flymake--diag-backend backend)
 (flymake--diag-accessor flymake-diagnostic-data flymake--diag-data backend)
 
+(defun flymake-diagnostic-beg (diag)
+  "Get Flymake diagnostic DIAG's start position."
+  (overlay-start (flymake--diag-overlay diag)))
+
+(defun flymake-diagnostic-end (diag)
+  "Get Flymake diagnostic DIAG's end position."
+  (overlay-end (flymake--diag-overlay diag)))
+
 (cl-defun flymake--overlays (&key beg end filter compare key)
   "Get flymake-related overlays.
 If BEG is non-nil and END is nil, consider only `overlays-at'
@@ -1294,8 +1300,8 @@ default) no filter is applied."
       (with-selected-window
           (display-buffer (current-buffer) other-window)
         (goto-char (flymake--diag-beg diag))
-        (pulse-momentary-highlight-region (flymake--diag-beg diag)
-                                          (flymake--diag-end diag)
+        (pulse-momentary-highlight-region (flymake-diagnostic-beg diag)
+                                          (flymake-diagnostic-end diag)
                                           'highlight))
       (current-buffer))))