servo: Merge #9946 - Added compiler lint ban on DOMRefCell (from yoava333:master); r=KiChjang

this resolves https://github.com/servo/servo/issues/9924

Source-Repo: https://github.com/servo/servo
Source-Revision: d23b7481d60f52f9e2fa72b6cd3de7eda05c2419

servo/components/plugins/lints/ban.rs

@@ -37,5 +37,11 @@ impl EarlyLintPass for BanPass {
             .is_some() {
             cx.span_lint(BANNED_TYPE, ty.span, "Banned type Cell<JSVal> detected. Use MutHeap<JSVal> instead")
         }
+        if match_ty_unwrap(ty, &["dom", "bindings", "cell", "DOMRefCell"])
+            .and_then(|t| t.get(0))
+            .and_then(|t| match_ty_unwrap(&**t, &["dom", "bindings", "js", "JS"]))
+            .is_some() {
+            cx.span_lint(BANNED_TYPE, ty.span, "Banned type DOMRefCell<JS<T>> detected. Use MutHeap<JS<T>> instead")
+        }
     }
 }

servo/components/servo/Cargo.lock

@@ -1472,6 +1472,7 @@ version = "0.0.1"
 dependencies = [
  "compiletest_helper 0.0.1",
  "plugins 0.0.1",
+ "script 0.0.1",
 ]
 
 [[package]]

servo/tests/compiletest/plugin/Cargo.toml

@@ -13,3 +13,6 @@ path = "../helper"
 
 [dependencies.plugins]
 path = "../../../components/plugins"
+
+[dependencies.script]
+path = "../../../components/script"

servo/tests/compiletest/plugin/compile-fail/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(plugins)]
+
+extern crate script;
+
+use script::dom::bindings::cell::DOMRefCell;
+use script::dom::bindings::js::JS;
+use script::dom::node::Node;
+
+struct Foo {
+    bar: DOMRefCell<JS<Node>>
+    //~^ ERROR Banned type DOMRefCell<JS<T>> detected. Use MutHeap<JS<T>> instead,
+}
+
+fn main() {}