Do not display highlights for clang-include-fixer-at-point

[tmarek]

Summary

When invoking clang-include-fixer-at-point, the QuerySymbolInfos point to offset 0, length 0. Rather than showing a hidden overlay, do not show any overlay at all for zero-length symbols.

[hokein]

LGTM, thanks!

include-fixer/tool/clang-include-fixer-test.el

(with-temp-buffer
     ;; Emacs treats the character immediately following a symbol as part of the
     ;; symbol.
     (should (equal (clang-include-fixer--symbol-at-point) "a"))
     (forward-char)
     (should (equal (clang-include-fixer--symbol-at-point) "bbb::cc"))
     (goto-char (point-max))
     (should (equal (clang-include-fixer--symbol-at-point) "bbb::cc"))))
 
+(ert-deftest clang-include-fixer--highlight ()
+  (with-temp-buffer
+    (insert "util::Status foo;\n")
+    (setq buffer-file-coding-system 'utf-8-unix)
+    (should (equal nil (clang-include-fixer--highlight
+                        '((Range . ((Offset . 0) (Length . 0)))))))
+    (let ((overlay (clang-include-fixer--highlight
+                    '((Range . ((Offset . 1) (Length . 12)))))))
+      (should (equal 2 (overlay-start overlay)))
+      (should (equal 14 (overlay-end overlay))))))
+
 ;;; clang-include-fixer-test.el ends here

include-fixer/tool/clang-include-fixer.el

 (defun clang-include-fixer--prompt-for-header (context)
   "Prompt the user for a single header.
 The choices are taken from the HeaderInfo elements in CONTEXT.
 They are replaced by the single element selected by the user."
   (let-alist context
     (let ((symbol (clang-include-fixer--symbol-name .QuerySymbolInfos))
           ;; Add temporary highlighting so that the user knows which
           ;; symbols the current session is about.
-          (overlays (mapcar #'clang-include-fixer--highlight .QuerySymbolInfos)))
+          (overlays (remove nil
+                            (mapcar #'clang-include-fixer--highlight .QuerySymbolInfos))))
       (unwind-protect
           (save-excursion
             ;; While prompting, go to the closest overlay so that the user sees
             ;; some context.
-            (goto-char (clang-include-fixer--closest-overlay overlays))
+            (when overlays
+              (goto-char (clang-include-fixer--closest-overlay overlays)))
             (cl-flet ((header (info) (let-alist info .Header)))
               ;; The header-infos is already sorted by include-fixer.
               (let* ((header (completing-read
                               (clang-include-fixer--format-message
                                "Select include for '%s': " symbol)
                               (mapcar #'header .HeaderInfos)
                               nil :require-match nil
                               'clang-include-fixer--history))
Raise a signal if the symbol name is not unique."
   (let ((symbols (delete-dups (mapcar (lambda (info)
                                         (let-alist info .RawIdentifier))
                                       symbol-infos))))
     (when (cdr symbols)
       (error "Multiple symbols %s returned" symbols))
     (car symbols)))
 
 (defun clang-include-fixer--highlight (symbol-info)
-  "Add an overlay to highlight SYMBOL-INFO.
-Return the overlay object."
-  (let ((overlay (let-alist symbol-info
-                   (make-overlay
+  "Add an overlay to highlight SYMBOL-INFO, if it points to a non-empty range.
+Return the overlay object, or nil."
+  (let-alist symbol-info
+    (unless (zerop .Range.Length)
+      (let ((overlay (make-overlay
                       (clang-include-fixer--filepos-to-bufferpos
                        .Range.Offset 'approximate)
                       (clang-include-fixer--filepos-to-bufferpos
-                     (+ .Range.Offset .Range.Length) 'approximate)))))
+                       (+ .Range.Offset .Range.Length) 'approximate))))
         (overlay-put overlay 'face 'clang-include-fixer-highlight)
-    overlay))
+        overlay))))
 
 (defun clang-include-fixer--closest-overlay (overlays)
   "Return the start of the overlay in OVERLAYS that is closest to point."
   (cl-check-type overlays cons)
   (let ((point (point))
         acc)
     (dolist (overlay overlays acc)
       (let ((start (overlay-start overlay)))