Merge pull request #521 from rust-lang/treesit-old-emacs

Fix tree-sitter integration for older emacs

Changelog.md

@@ -2,3 +2,4 @@
 
 - Add support for treesitter mode.
 - Fix warnings resulting from rust-utils.el. [Fixes #509](https://github.com/rust-lang/rust-mode/issues/509).
+- Fix tree sitter mode with hooks integraiton. [Fixes #516](https://github.com/rust-lang/rust-mode/issues/516).

rust-mode-treesitter.el

@@ -6,17 +6,21 @@
 ;;; Code:
 
 ;;;###autoload
-(require 'treesit)
-(require 'rust-ts-mode)
+(when (version<= "29.1" emacs-version)
+  ;; We have the when macro because of
+  ;; https://github.com/rust-lang/rust-mode/issues/520
+  (require 'treesit)
+  (require 'rust-ts-mode)
+  (require 'rust-common)
 
-(define-derived-mode rust-mode rust-ts-mode "Rust"
-  "Major mode for Rust code.
+  (define-derived-mode rust-mode rust-ts-mode "Rust"
+    "Major mode for Rust code.
 
 \\{rust-mode-map}"
-  :group 'rust-mode
+    :group 'rust-mode
 
-  (add-hook 'before-save-hook rust-before-save-hook nil t)
-  (add-hook 'after-save-hook rust-after-save-hook nil t))
+    (add-hook 'before-save-hook rust-before-save-hook nil t)
+    (add-hook 'after-save-hook rust-after-save-hook nil t)))
 
 (provide 'rust-mode-treesitter)
 ;;; rust-mode-treesitter.el ends here