Rewrite the ban-type lint in Python

Delete old rust ban lint and move tests to python tidy

Fix ban lint regex and fix test

python/tidy/servo_tidy_tests/ban-domrefcell.rs

@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(plugin)]
+#![plugin(script_plugins)]
+
+extern crate script;
+
+use script::test::DOMRefCell;
+use script::test::JS;
+use script::test::Node;
+
+struct Foo {
+    bar: DOMRefCell<JS<Node>>
+    //~^ ERROR Banned type DOMRefCell<JS<T>> detected. Use MutJS<JS<T>> instead
+}
+
+fn main() {}

python/tidy/servo_tidy_tests/ban.rs

@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(plugin)]
+#![plugin(script_plugins)]
+
+extern crate js;
+
+use js::jsval::JSVal;
+use std::cell::Cell;
+use std::cell::UnsafeCell;
+
+struct Foo {
+    bar: Cell<JSVal>,
+    //~^ ERROR Banned type Cell<JSVal> detected. Use MutJS<JSVal> instead
+    foo: UnsafeCell<JSVal>
+    //~^ NOT AN ERROR
+}
+
+fn main() {}

python/tidy/servo_tidy_tests/test_tidy.py

@@ -140,6 +140,14 @@ class CheckTidiness(unittest.TestCase):
         self.assertTrue('feature attribute is not in alphabetical order' in feature_errors.next()[2])
         self.assertNoMoreErrors(feature_errors)
 
+        ban_errors = tidy.collect_errors_for_files(iterFile('ban.rs'), [], [tidy.check_rust], print_text=False)
+        self.assertEqual('Banned type Cell<JSVal> detected. Use MutJS<JSVal> instead', ban_errors.next()[2])
+        self.assertNoMoreErrors(ban_errors)
+
+        ban_errors = tidy.collect_errors_for_files(iterFile('ban-domrefcell.rs'), [], [tidy.check_rust], print_text=False)
+        self.assertEqual('Banned type DOMRefCell<JS<T>> detected. Use MutJS<JS<T>> instead', ban_errors.next()[2])
+        self.assertNoMoreErrors(ban_errors)
+
     def test_spec_link(self):
         tidy.SPEC_BASE_PATH = base_path
         errors = tidy.collect_errors_for_files(iterFile('speclink.rs'), [], [tidy.check_spec], print_text=False)