Error in symex-ts--handle-tree-modification for internal TS library

Support for handling tree changes needs to be implemented differently
for the internal tree sitter library.

symex-transformations-ts.el

@@ -38,41 +38,42 @@ selected according to the ranges that have changed."
       ;; TODO: Implement symex-ts--handle-tree-modification for the internal tree sitter library
       '(error "Unable to perform edit: the Emacs internal tree sitter library is not yet supported")
 
-      (let ((prev-tree (gensym))
-            (res (gensym))
-            (changed-ranges (gensym))
-            (orig-pos (gensym)))
-
-        `(let ((,prev-tree tree-sitter-tree)
-               (,orig-pos (point)))
-
-           `(let ((,prev-tree tree-sitter-tree))
-
-              ;; Execute BODY, bind to RES
-              (let ((,res (progn ,@body)))
-
-                ;; Move point to the first changed range if possible
-                (when (and (> (length ,changed-ranges) 0)
-                           (> (length (elt ,changed-ranges 0)) 0))
-                  (let ((new-pos (elt (elt ,changed-ranges 0) 0)))
-                    ;; don't move point to before the
-                    ;; original point location
-                    (if (< new-pos ,orig-pos)
-                        (goto-char ,orig-pos)
-                      (goto-char new-pos)
-                      ;; If the change starts on a carriage return, move
-                      ;; forward one character
-                      (when (char-equal ?\C-j (char-after))
-                        (forward-char 1))))))
-
-              ;; Update current node from point and reindent if necessary
-              (symex-ts-set-current-node-from-point)
-              (when symex-highlight-p
-                (symex--update-overlay))
-              (indent-according-to-mode))
+    (let ((prev-tree (gensym))
+          (res (gensym))
+          (changed-ranges (gensym)))
+
+      `(let ((,prev-tree tree-sitter-tree))
+
+         ;; Execute BODY, bind to RES
+         (let ((,res (progn ,@body)))
+
+           ;; Get changes from previous to current tree
+           (let ((,changed-ranges (tsc-changed-ranges ,prev-tree tree-sitter-tree)))
+
+             ;; Move point to the first changed range if possible
+             (when (and (> (length ,changed-ranges) 0)
+                        (> (length (elt ,changed-ranges 0)) 0))
+               (goto-char (elt (elt ,changed-ranges 0) 0))
+
+               ;; If the change starts on a carriage return, move
+               ;; forward one character
+               (when (char-equal ?\C-j (char-after))
+                 (forward-char 1)))
+
+             ;; Update current node from point and reindent if necessary
+             (symex-ts-set-current-node-from-point)
+             (when symex-highlight-p
+               (symex--update-overlay))
+             (indent-according-to-mode))
 
            ;; Return the result of evaluating BODY
-           ,res))))
+           ,res)))))
+
+(defun symex-ts-change-node-forward (&optional count)
+  "Delete COUNT nodes forward from the current node and enter Insert state."
+  (interactive "p")
+  (save-excursion (symex-ts-delete-node-forward count t))
+  (evil-insert-state 1))
 
 (defun symex-ts-clear ()
   "Clear contents of symex."