Eglot: fix edge case when deleting inlay hint overlays

When asked to update hints in a region (FROM TO),
eglot--update-hints-1 first deletes the existing hints.  It must
however take care to delete all overlays that logically belong to the
region, even if they don't physically belong to it, e.g. inlay
overlays spanning (FROM-1 FROM) and having a 'after-string' property.

* lisp/progmodes/eglot.el (eglot--update-hints-1): Fix edge case.

1 files changed, 13 insertions, 1 deletions

diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index ed554087084..0fab8db0e83 100644
--- a/lisp/progmodes/eglot.el
+++ b/lisp/progmodes/eglot.el
@@ -3664,7 +3664,19 @@ If NOERROR, return predicate, else erroring function."
      :success-fn (lambda (hints)
                    (eglot--when-live-buffer buf
                      (eglot--widening
-                      (remove-overlays from to 'eglot--inlay-hint t)
+                      ;; Overlays ending right at FROM with an
+                      ;; `after-string' property logically belong to
+                      ;; the (FROM TO) region.  Likewise, such
+                      ;; overlays ending at TO don't logically belong
+                      ;; to it.
+                      (dolist (o (overlays-in (1- from) to))
+                        (when (and (overlay-get o 'eglot--inlay-hint)
+                                   (cond ((eq (overlay-end o) from)
+                                          (overlay-get o 'after-string))
+                                         ((eq (overlay-end o) to)
+                                          (overlay-get o 'before-string))
+                                         (t)))
+                          (delete-overlay o)))
                       (mapc paint-hint hints))))
      :deferred 'eglot--update-hints-1)))